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Biological invasions are a major driver of biodiversity loss and socioeconomic burden globally. As invasion rates accelerate worldwide, understanding past invasion dynamics is essential to inform predictions of future invaders and impacts. Owing to a high diversity of pathways and current biosecurity gaps, aquatic systems near urban centres are especially susceptible to alien species establishments. Here, we compiled and compared alien species lists for three different aquatic recipient regions spanning the North Atlantic: Chesapeake Bay, Great Lakes-St. Lawrence River and North and Baltic Seas. Each system is a major trade centre, with a history of invasions, and characterised by a strong natural salinity gradient. Our goal was to compare the alien species across systems, to test for similarities in the taxonomic composition and geographic origin as well as species overlap among the three regions. We selected specific macroinvertebrate, algae and fish taxa for analysis, to control for uneven taxonomic and biogeographic resolution across regions. Cumulatively, we identified 326 individual alien species established in these aquatic systems, with the North and Baltic Seas most invaded overall (163), followed by Great Lakes-St. Lawrence River (84) and Chesapeake Bay (79). Most invasions were from Ponto-Caspian, Eurasian, Northwest Pacific, Northwest Atlantic and North American origins, and mostly comprised Arthropoda, Chordata, Mollusca and Annelida. However, origins and taxonomies differed significantly among destinations, with Ponto-Caspian species particularly successful invaders to the North and Baltic Seas then Great Lakes-St. Lawrence River, but less so to Chesapeake Bay. Nevertheless, approximately eight tenths of invaders established in only one region, indicating disparate invasion patterns and a high potential for future aliens to accrue from increasingly diverse source pools and pathways. These results support biosecurity strategies that consider a broad range of geographic origins and taxonomic groups to limit the translocation, arrival and spread of alien species worldwide.

Predicting the ecological impacts of invasive species is impeded by context-dependencies that can mediate the strength of trophic interactions. Reproductive status is a pervasive context across trophic and taxonomic groups, yet has mostly been neglected in studies of invader impact. The present study examines the influence of the reproductive cycle on predatory impacts of a known damaging invasive freshwater crustacean, Gammarus pulex (Amphipoda), using a comparative functional response approach. Across females that were non-ovigerous, or had immature- or mature-stage embryonic broods, all G. pulex exhibited potentially prey destabilising Type II functional responses towards chironomid larvae. Attack rates were highest by immature embryonic brood stages, and significantly lower by mature embryonic brood stages. Conversely, handling times were consistently lower, and hence maximum feeding rates higher, where broods were present as compared to absent. These predatory patterns may reflect changing resource demands for progeny development across the reproductive cycle, the influence of brood bulk, female moult stage and/or motivational aspects of feeding, such as avoidance of filial cannibalism. Accordingly, many aspects of reproduction may alter the intensity of predatory impacts by invasive species. Future studies considering invader impacts should consider the influence of sex and reproductive status to more holistically quantify and predict population-level invader impacts.

In aquatic systems, invasive submerged macrophytes considerably alter the structure and functioning of communities, thus potentially compromising ecosystem services. The prolific spread of invasive macrophytes is often aided by vegetative fragment propagation, yet the contributions of various commonly occurring invertebrates to such fragmentation are often unquantified. In the present study, we examine fragmentary spread of invasive macrophytes by a group of shredder-herbivores, larval caddisflies. Through novel application of the comparative functional response (FR; resource use as a function of density) approach to the native case-building speciesLimnephilus lunatus, we compared utilisation of non-native waterweedsElodea canadensisandE. nuttalliiin mono- and polycultures. Furthermore, we quantified de-cased and cased caddisfly-induced fragment production and length changes among non-nativeE. canadensis,E. nuttallii,Crassula helmsiiandLagarosiphon majorunder two different plant orientations: horizontal (floating) versus vertical (upright) growth forms. Larval caddisflies exhibited Type II (hyperbolic) FRs towards bothElodeaspecies, and utilised each plant at similar rates when plants were provided separately. When plant species were presented in combination horizontally,E. canadensiswas significantly less utilised compared toE. nuttallii, corroborating observations in the field. De-cased larvae produced new plant fragments for all four aquatic macrophytes, whereas cased larvae fragmented plants significantly less.Elodea nuttaliiandC. helmsiiwere fragmented the most overall.Crassula helmsiiwas utilised to the greatest extent when plants were horizontally orientated, andElodeaspecies when vertically orientated. This study identifies and quantifies a mechanism from a novel species group that may contribute to the spread of invasive macrophytes in aquatic systems. Whilst exploititative interactions are thought to impede invasion success, here we demonstrate how resource utilisation by a resident species may exacerbate propagule pressure from an invasive species.

Predator-predator interactions, or “multiple predator effects” (MPEs), are pervasive in the structuring of communities and complicate predictive quantifications of ecosystem dynamics. The nature of MPEs is also context-dependent, manifesting differently among species, prey densities and habitat structures. However, there has hitherto been a lack of consideration for the implications of intraspecific demographic variation within populations for the strength of MPEs. The present study extends MPE concepts to examine intraspecific interactions among male and female predators across differences in prey densities using a functional response approach. Focusing on a copepod-mosquito model predator-prey system, interaction strengths of different sex ratio pairs of Lovenula raynerae were quantified towards larval Culex pipiens complex prey, with observations compared to both additive and substitutive model predictions. Copepods exhibited destabilising Type II functional responses in all treatments, with female copepods significantly more voracious than males under multiple predator groups. Lovenula raynerae exhibited significantly negative MPEs overall which resulted in prey risk reductions. However, whilst not statistically clear, the magnitude of antagonistic interactions subtly differed among predator-predator compositions and prey densities, with female-female antagonisms generally prevalent at low prey densities, and male-male negative interactions greater under high prey densities. Mixed-sex copepod group predation was predicted by both additive and substitutive models, and additive models generated significantly higher consumption estimates than substitutive equivalents given that their predictions were based on the absence of antagonistic non-trophic interactions. We propose the importance of internal population sex demographics as a further context-dependency which influences the nature of MPEs, with demographic implications requiring investigation across other taxonomic and trophic groups.

Biosecurity protocols designed to prevent further spread of invasive alien species have become a key component of invader management strategies. However, spread-prevention of invasive peracarids is especially difficult due to ineffectiveness of detection and treatment options. For instance, bloody-red mysid shrimp, Hemimysis anomala, is a high impact ecosystem-destabilising invader, which continues to spread in both Europe and North America. Here, we examine the effectiveness of two commonly used aquatic disinfectants (Virasure®/Virkon® Aquatic), and steam treatments (≥ 100 °C) to kill H. anomala. Specimens were exposed to 1% disinfectant solutions for complete immersion or mist-spray treatments, both lasting 60 s. Steam exposures lasted for 10 or 30 s. All treatments caused 100% mortality of H. anomala. Accordingly, it appears that relatively brief exposures to disinfectant and steam treatments can curtail further H. anomala spread. Therefore, these treatments should be used to decontaminate all equipment, from wetsuits to boats. In particular, steam and disinfectant spray treatments may be useful for decontamination of large, complex equipment, such as vehicles, trailers, outboard motors, or live wells on fishing boats.

Increasing rates of invasions in ecosystems worldwide necessitate experiments to determine the role of biotic interactions in the success and impact of multiple alien species. Here, we examined competitive and facilitative interactions among various combinations of three widespread and often co‐occurring invaders: the zebra mussel Dreissena polymorpha, and the macrophytes Elodea canadensis and Elodea nuttallii. Using a mesocosm‐based, factorial experimental design, we assessed the effect of interspecific competition on macrophyte growth rates in the absence and presence at varying biomass of D. polymorpha. Growth rates (wet g/day) of E. canadensis and E. nuttallii were similar when grown in isolation. When grown together, in the absence of D. polymorpha, E. canadensis growth was not significantly reduced in the presence of E. nuttallii and vice versa. In the presence of D. polymorpha (26.0 ± 1 mm), monocultural growth of E. canadensis was largely unaffected, while E. nuttallii growth was strongly enhanced. Low (2.64 g) and medium (3.96 g) mussel biomass led to negative interspecific effects between E. canadensis and E. nuttallii; at high (5.28 g) mussel biomass, the effect of interspecific competition was negated. Overall, D. polymorpha alleviated competitive interactions between the two invasive macrophytes when all three species co‐occurred, and substantially enhanced growth of E. nuttallii with increasing mussel biomass, thereby suggesting a possible influence on the relative dominance of these macrophytes in the field. Our study demonstrates how facilitations can cause shifts in dominance among closely related invaders. The consequences of such facilitations for the structure and function of communities remain to be explored generally.

Aquatic invasive alien species (IAS) negatively impact freshwater ecosystems worldwide. As suppression and eradication of established invader populations are often complex, costly and resource-intensive, the prevention of further invader spread is considered a key aspect of proactive management measures. Although broad-spectrum aquatic disinfectants have been suggested as a suitable decontamination mechanism to enhance invader spread-prevention strategies, inconsistencies concerning their effectiveness are reported within the literature. Here, we examine the use of two aquatic disinfectants, which were developed to kill damaging microbes, to induce substantial degradation of the apical fragmentary propagules of five invasive macrophytes: Crassula helmsii (Kirk) Cockayne; Egeria densa Planchon; Elodea canadensis Michx; Hydrocotyle ranunculoides Linnaeus; Lagarosiphon major (Ridley) Moss. Apical fragments were exposed to 0% (0 g L-1), 2% (20 g L-1) or 4% (40 g L-1) solutions of Virkon® Aquatic and Virasure® Aquatic, for submergence treatments of five, fifteen, thirty or sixty minutes. After 28 days, degradation of treated fragments was significantly greater than that of control groups, particularly for 4% solutions and longer exposure times. Despite this, sustained viability in relation to shoot and/or root regrowth was exhibited by almost all plant species. However, new shoot growth rates were significantly reduced following exposure to all treatments. At matched concentrations, there was no significant difference between the two disinfectants. Overall, it appears that the examined aquatic disinfectants will not curtail the spread of these invasive macrophytes. Yet, longer submergence times, multiple applications and synergistic effects of different biosecurity treatments may enhance preventative measures against further spread and this requires investigation.

Highlights: • Temperature, dung mass and beetle density affected dung utilisation services. • Dung utilisation increased significantly with temperature and density. • Largest Khepher prodigiosus exhibited highest dung utilisation among species. • Emergent effects suggest species respond differently to warming and beetle density. • Ecosystem services provision requires surveillance under global climate change. Abstract: Increases in the frequency and magnitude of suboptimal temperatures as a result of climate change are subjecting insects to unprecedented stresses. This may negatively affect their fitness and the efficiency of their ecosystem service provision. Dung beetles are ecosystem service providers: through feeding on and burying dung, they facilitate nutrient recycling, secondary seed dispersal, parasite control, soil bioturbation and dung decomposition. As such, prediction of how dung beetles respond to multiple anthropogenic environmental changes is critical for the conservation of ecosystem services. Here, we quantified ecosystem services via dung utilisation and dung ball production in three telecoprid species: Allogymnopleurus indigaceous, Scarabaeus zambezianus and Khepher prodigiosus. We examined ecosystem service efficiency factorially under different beetle densities towards different dung masses and under three temperature treatments (21 °C, 28 °C and 35 °C). Khepher prodigiosus, exhibited greatest dung utilisation efficiency overall across dung masses, compared to both S. zambezianus and A. indigaceous. Dung removal was exhibited under all the tested temperatures by all tested species, and therefore the sub-optimal temperatures employed here did not fully inhibit ecosystem service delivery. However, emergent effects among temperatures, beetle species and beetle density further affected removal efficiency: S. zambezianus and A. indigaceous utilisation increased with both warming and beetle density, whereas K. prodigiosus performance was less temperature- and density-dependent. Beetles also tended to exhibit positive density-dependence as dung supply increased. The numbers of dung balls produced differed across species, and increased with temperature and densities, with S. zambezianus producing significantly most balls overall. Our study provides novel evidence for differential density-dependent ecosystem service delivery among species across stressful temperature regimes and emergent effects for dung mass utilisation. This information is essential for biodiversity-ecosystem-function and is critical for the conservation of functionally efficacious species, with implications for natural capital conservation policy in rapidly changing environments.

The rate of biological invasions is growing unprecedentedly, threatening ecological and socioeconomic systems worldwide. Quantitative understandings of invasion temporal trajectories are essential to discern current and future economic impacts of invaders, and then to inform future management strategies. Here, we examine the temporal trends of cumulative invasion costs by developing and testing a novel mathematical model with a population dynamical approach based on logistic growth. This model characterises temporal cost developments into four curve types (I - IV), each with distinct mathematical and qualitative properties, allowing for the parameterization of maximum cumulative costs, carrying capacities and growth rates. We test our model using damage cost data for eight genera (Rattus, Aedes, Canis, Oryctolagus, Sturnus, Ceratitis, Sus and Lymantria) extracted from the InvaCost database – which is the most up-to-date and comprehensive global compilation of economic cost estimates associated with invasive alien species. We find fundamental differences in the temporal dynamics of damage costs among genera, indicating they depend on invasion duration, species ecology and impacted sectors of economic activity. The fitted cost curves indicate a lack of broadscale support for saturation between invader density and impact, including for Canis, Oryctolagus and Lymantria, whereby costs continue to increase with no sign of saturation. For other taxa, predicted saturations may arise from data availability issues resulting from an underreporting of costs in many invaded regions. Overall, this population dynamical approach can produce cost trajectories for additional existing and emerging species, and can estimate the ecological parameters governing the linkage between population dynamics and cost dynamics.

Habitat structure can profoundly influence interaction strengths between predators and prey. Spatio-temporal habitat structure in temporary wetland ecosystems is particularly variable because of fluctuations in water levels and vegetation colonisation dynamics. Demographic characteristics within animal populations may also alter the influence of habitat structure on biotic interactions, but have remained untested. Here, we investigate the influence of vegetation habitat structure on the consumption of larval mosquito prey by the calanoid copepod Lovenula raynerae, a temporary pond specialist. Increased habitat complexity reduced predation, and gravid female copepods were generally more voracious than male copepods in simplified habitats. However, sexes were more similar as habitat complexity increased. Type II functional responses were exhibited by the copepods irrespective of habitat complexity and sex, owing to consistent high prey acquisition at low prey densities. Attack rates by copepods were relatively unaffected by the complexity gradient, whilst handling times lengthened under more complex environments in gravid female copepods. We demonstrate emergent effects of habitat complexity across species demographics, with predation by males more robust to differences in habitat complexity than females. For ecosystems such as temporary ponds where sex-skewed predator ratios develop, our laboratory findings suggest habitat complexity and sex demographics mediate prey risk.

Despite voluminous literature identifying invasive species impacts, understandings of monetary costs remain limited. Recently, profound impacts have been attributed to invasive crustaceans, but associated monetary costs lack synthesis. Here, we analyse globally reported costs of invasive freshwater crayfish across taxonomic, spatial and temporal descriptors. Moreover, we compare their cost magnitude to other invasive crustaceans — crabs, amphipods and lobsters. Between 2000 and 2020, crayfish caused US$ 1.28 billion in reported costs; the vast majority (95%) attributed to Astacidae (principally the signal crayfish Pacifastacus leniusculus) and the remainder to Cambaridae. According to reports, crayfish costs mostly impacted European economies (US$ 1.23 billion), followed by costs reported for North America and Asia. Despite well-known damages caused by invasive crayfish, costs were unreported elsewhere, highlighting knowledge gaps and challenges in cost quantifications. Invasive crayfish costs increased exponentially in the last two decades, averaging at US$ 61 million per-annum. Invasive crabs caused costs of similar magnitude (US$ 1.25 billion; US$ 53 million per-annum) but were mostly confined to North America (95%). Damage-related costs dominated for both crayfish (83%) and crabs (99%), with management spending lacking. Reported economic impacts from amphipods (US$ 178.8 thousand) and lobsters (US$ 44.6 thousand) were considerably lower. We identify burgeoning economic costs from these invasive groups yet highlight pervasive knowledge gaps at multiple scales. Further cost reporting is required to better-ascertain the true scale of monetary costs caused by invasive aquatic crustaceans.

The authors would like to thank the Engineering and Physical Sciences Research Council (EPSRC) [EP/P029280/1], the Coordination for the Improvement of Higher Education Personnel - CAPES [PROEX 20/2016 and PrInt 88887.311806/2018–00], and the Brazilian National Research Council – CNPq [403116/2016–3 and 304164/2017–8] for funding this research. As per EPSRC requirement all data will be made publicly available via the Robert Gordon University's open access repository OpenAIR@RGU. Further, the first author also acknowledges the scholarship from the Brazilian National Research Council - CNPq. To date, the high cost of supplying UV irradiation has prevented the widespread application of UV photolysis and titanium dioxide based photocatalysis in removing undesirable organics in the water treatment sector. To overcome this problem, the use of UV-LEDs (365 nm) for photolysis and heterogeneous photocatalysis applying TiO2 coated glass beads under UV-LED illumination (365 nm) in a pilot scale reactor for the elimination of Microcystis aeruginosa PCC7813 and four microcystin analogues (MC-LR, -LY, -LW, -LF) with a view to deployment in drinking water reservoirs was investigated. UV-A (365 nm) photolysis was shown to be more effective than the UV/TiO2 photocatalytic system for the removal of Microcystis aeruginosa cells and microcystins. During photolysis, cell density significantly decreased over 5 days from an initial concentration of 5.8 × 106 cells mL−1 until few cells were left. Both intra- and extracellular microcystin concentrations were significantly reduced by 100 and 92 %, respectively, by day 5 of the UV treatment for all microcystin analogues. During UV/TiO2 treatment, there was great variability between replicates, making prediction of the effect on cyanobacterial cell and toxin behavior difficult. Postprint Postprint

The Rosaceae family has striking phenotypic diversity and high syntenic conservation.Gillenia trifoliatais sister species to the Maleae tribe of apple and ~1000 other species.Gilleniahas many putative ancestral features, such as herb/sub-shrub habit, dry fruit-bearing and nine base chromosomes. This coalescence of ancestral characters in a phylogenetically important species, positionsGilleniaas a ‘rosetta stone’ for translational science within Rosaceae. We present genomic and phenological resources to facilitate the use ofGilleniafor this purpose. TheGilleniagenome is the first fully annotated chromosome-level assembly with an ancestral genome complement (x = 9), and with it we developed an improved model of the Rosaceae ancestral genome. MADS and NAC gene family analyses revealed genome dynamics correlated with growth and reproduction and we demonstrate howGilleniacan be a negative control for studying fleshy fruit development in Rosaceae.

Highlights: • Warming and desalination cause mortality of sea urchin Paracentrotus lividus. • Total mortality displayed at 27 °C and 25 salinity in one population. • Salinity effects were strongest at the highest temperature. • Multiple stressors associated with environmental change threaten keystone species. Abstract: Aquatic ecosystems are threatened by multiple stressors which might interact in non-additive ways. Two key stressors in marine systems that are likely to be mediated by ongoing climate change are temperature and salinity. Here, we experimentally examine the influence of warming and desalination on mortality rates of a key herbivorous sea urchin, Paracentrotus lividus, between two populations over time. Mortality rates were significantly increased by warming and desalination as individual stressors, with up to total mortality exhibited at the highest water temperature (27 °C) and lowest salinity (25). However, these stressors interacted, with desalination significantly exacerbating mortality rates at the highest temperature, but not under lower thermal regimes (21 °C and 25 °C). Mortality rates were relatively consistent between two sea urchin populations. Overall, temperature and salinity stressors can significantly interact to mediate mortality rates of key aquatic species, in ways that cannot be predicted by considering individual stressors in isolation. Future research should incorporate multiple environmental contexts to better understand and predict species responses to changing climate.

Highlights: • Baetidae, Corixidae, Coenogrionidae, Dytiscidae and Physidae were the most abundant families. • Functional feeding group ratios indicated that all sites were strongly autotrophic. • Environmental variables and fish had an influence on macroinvertebrate community. • Different macroinvertebrate taxa respond differently to seasonal changes. Abstract: Wetlands in the Global South are under increasing pressure due to multiple stressors associated with global change. Water and sediment quality assessments, as well as biomonitoring using macroinvertebrates communities, are fundamental tools for informing wetland condition and management strategies. Here, we examine water and sediment parameters affecting aquatic macroinvertebrates in Nlyslvey Wetland, Limpopo Province, South Africa. Water quality, sediments, fish and macroinvertebrate community data were collected across three seasons (hot-dry, hot-wet, cool-dry) from five sites. Baetidae, Corixidae, Coenogrionidae, Dytiscidae and Physidae were the most abundant and dominant families, with functional feeding group (FFG) ratios indicating that all sites were strongly autotrophic, had high predator-prey ratios, few shredders and had a stable substrate across seasons. Fish abundances increased significantly towards the cool-dry season. Based on redundancy analysis, P, Ca, pH, Cu and Na were strongly positively associated with macroinvertebrates, including Physidae, Corixidae, Planorbidae, Ostracoda, Potamonautidae and Hydropyschidae; turbidity and sulphur were associated with Dytiscidae, Oligochaetae, Libellulidae, Gerridae and Dixidae, and fish abundance, Fe, oxygen reduction potential and total dissolved solids were negatively associated with Baetidae, Belostomatidae, Hydrophilidae and Leptoceridae. Therefore, these variables accounted for large levels of variation in macroinvertebrate families, with the cool-dry season clearly distinguished from the hot-wet and hot-dry seasons according to functional feeding groups. Being a protected area, this information could provide a useful baseline for further studies into wetlands in the region subject to greater anthropogenic stresses, as well as future studies in this Ramsar site under global changes. Further studies are required to assess the importance of environmental factors influencing the richness and distribution of macroinvertebrate communities in wetlands under growing anthropogenic pressures.

1. Low temperatures affect insect functioning and population dynamics. Although temperate species cope with low temperatures better than their tropical counterparts, increasing temperature variability due to climate change exposes tropical species to frequent cold stress. For keystone insect species providing important ecosystem services, low-temperature tolerances, and behavioural responses remain unknown, hampering predictions under climate change. 2. The present study examined low-temperature physiology [critical thermal minima (CTmin) and chill coma recovery time (CCRT)] of six dung beetle species across three activity times: diurnal Allogymnopleurus indigaceous (Reiche) and Euoniticellus intermedius (Reiche); crepuscular Onthophagus alexis (Klug) and Onthophagus gazella (Fabricius), and; nocturnal Copris elephenor (Klug) and Scarabaeus zambezianus (Peringuey). Further, ecological service delivery (dung removal) was examined between diurnal and nocturnal species across the temperature regimes. 3. Nocturnal species had significantly greater cold tolerance than both crepuscular and diurnal species, while CCRT was significantly shortest in diurnal than both crepuscular and nocturnal species. Dung ball production between diurnal and nocturnal species interacted with temperature, with diurnal species producing significantly fewer balls at low temperatures, while nocturnal beetles were not significantly affected. In turn, nocturnal species produced significantly larger balls than the diurnal species across temperatures. Effects of temperature regime shifts were intertwined with the foraging ecology of individual species. 4. Future research should quantify species' functional responses toward different amounts of dung masses as stressful temperatures increase. 5. Results are significant for determination of species thermal ranges and predicting costs of low-temperature stress through reduced ecological services under shifting thermal environments.

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves. Fil: Coughlan, Neil E.. The Queens University of Belfast; Irlanda. University College Cork; Irlanda Fil: Cunningham, Eoghan M.. The Queens University of Belfast; Irlanda Fil: Cuthbert, Ross N.. The Queens University of Belfast; Irlanda. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Joyce, Patrick W. S.. The Queens University of Belfast; Irlanda Fil: Anastácio, Pedro. Universidade de Évora; Portugal Fil: Banha, Filipe. Universidade de Évora; Portugal Fil: Bonel, Nicolás. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; Argentina Fil: Bradbeer, Stephanie J.. University of Leeds; Reino Unido Fil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; Alemania Fil: Butitta, Vince L.. University of Wisconsin; Estados Unidos Fil: Cadková, Zuzana. Czech University of Life Sciences; República Checa Fil: Dick, Jaimie T. A.. The Queens University of Belfast; Irlanda Fil: Douda, Karel. Czech University of Life Sciences; República Checa Fil: Eagling, Lawrence E.. The Queens University of Belfast; Irlanda Fil: Ferreira Rodríguez, Noé. Universidad de Vigo; España Fil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Johansson, Mattias L.. University of North Georgia; Estados Unidos Fil: Kregting, Louise. The Queens University of Belfast; Irlanda Fil: Labecka, Anna Maria. Jagiellonian University; Polonia Fil: Li, Deliang. Hunan Agricultural University; China Fil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina Fil: Marescaux, Jonathan. University of Namur; Bélgica. e-biom; Bélgica Fil: Morris, Todd J.. Fisheries and Ocean Canada; Canadá Fil: Nowakowska, Patrycja. University of Gdansk; Polonia Fil: Ozgo, Malgorzata. Kazimierz Wielki University; Polonia Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Peribáñez, Miguel A.. Universidad de Zaragoza; España Fil: Riccardi, Nicoletta. Consiglio Nazionale delle Ricerche; Italia Fil: Smith, Emily R. C.. University College London; Estados Unidos Fil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentina

Highlights: • Salinity can be highly variable spatiotemporally in enclosed sea systems. • Functional response of invasive mud crab Rhithropanopeus harrisii quantified. • Invasive crab feeding followed a hyperbolic Type II functional response. • Feeding rates were highest at 10 ppt and 7 ppt compared to 4 ppt. • Ecological impacts are reduced at the lowest salinity level. Abstract: Environmental gradients may alter the ecological impacts of invasive alien species. In marine systems such as the Baltic Sea, current salinity is variable and seawater freshening is projected in future, potentially facilitating novel keystone predators. Here, we examine the influence of salinity variation in the western Baltic Sea (i.e. ambient 10, then 7 and 4 ppt) on the functional response (FR) of the Harris mud crab Rhithropanopeus harrisii towards benthic macroinvertebrate prey at different densities. Rhithropanopeus harrisii displayed a Type II FR across salinities towards larval chironomids, due to a consistently high resource consumption rate at low prey densities. Feeding rates were significantly reduced at 4 ppt (mean 6 chironomid prey killed day−1) compared to 10 ppt and 7 ppt (9 killed day−1). Search efficiencies tended to be greatest at 10 ppt, whereas handling times were shortest — and maximum feeding rate highest — at the intermediate 7 ppt. These results suggest a slight reduction in predatory impact by R. harrisii at lower salinities. Nevertheless, across most prey densities, FRs were not significantly different, indicating sustained interaction strength across a range of salinity regimes.

Temperature and dehydration stress are two major co-occurring environmental stressors threatening the physiology, biochemistry, and ecology of insects. As such, understanding adaptive responses to desiccation stress is critical for predicting climate change impacts, particularly its influence on insect invasions. Here, we assessed water balance and desiccation resistance of the invasive Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae), and infer how eco-physiology shapes its niche. We measured basal body water and lipid content, water loss rates (WLRs), and desiccation resistance in larvae (second to fourth instars) and adults. Body -water, -lipid, and WLRs significantly varied across life stages. Second instars recorded the lowest while fourth instars exhibited the highest body water and lipid content. Adult body water and lipid content were higher than second and third instars and lower than fourth instars while proportion of body water and lipid contents were highest in adults and second larval instars respectively. Water loss rates were significantly highest in fourth-instar larvae compared to other life stages, but differences among stages were less apparent at longer exposure durations (48 h). Desiccation resistance assays showed that second instars had greatest mortality while fourth-instar larvae and adults were the most desiccation tolerant. Our results show that T. absoluta fourth-instar larvae and adults are the most resilient developmental stages and potentially contribute most to the invasion success of the pest in arid environments. Incorporation of these species-specific eco-physiological traits in predictive models can help refine invasive species potential spread under changing climates.

Invasive alien species are a well-known and pervasive threat to global biodiversity and human well-being. Despite substantial impacts of invasive alien species, quantitative syntheses of monetary costs incurred from invasions in national economies are often missing. As a consequence, adequate resource allocation for management responses to invasions has been inhibited, because cost-benefit analysis of management actions cannot be derived. To determine the economic cost of invasions in Germany, a Central European country with the 4th largest GDP in the world, we analysed published data collected from the first global assessment of economic costs of invasive alien species. Overall, economic costs were estimated at US$ 9.8 billion between 1960 and 2020, including US$ 8.9 billion in potential costs. The potential costs were mostly linked to extrapolated costs of the American bullfrog Lithobates catesbeianus, the black cherry Prunus serotina and two mammals: the muskrat Ondatra zibethicus and the American mink Neovison vison. Observed costs were driven by a broad range of taxa and mostly associated with control-related spending and resource damages or losses. We identified a considerable increase in costs relative to previous estimates and through time. Importantly, of the 2,249 alien and 181 invasive species reported in Germany, only 28 species had recorded economic costs. Therefore, total quantifications of invasive species costs here should be seen as very conservative. Our findings highlight a distinct lack of information in the openly-accessible literature and governmental sources on invasion costs at the national level, masking the highly-probable existence of much greater costs of invasions in Germany. In addition, given that invasion rates are increasing, economic costs are expected to further increase. The evaluation and reporting of economic costs need to be improved in order to deliver a basis for effective mitigation and management of invasions on national and international economies. Wirtschaftliche Kosten invasiver Arten in Deutschland. Invasive gebietsfremde Arten sind eine bekannte und weit verbreitete Bedrohung für die globale Artenvielfalt und das Wohlergehen des Menschen. Trotz erheblicher Auswirkungen invasiver gebietsfremder Arten fehlen häufig quantitative Synthesen der finanziellen Kosten, die durch Invasionen entstehen. Infolgedessen wurde eine angemessene Ressourcenzuweisung für Managementreaktionen auf Invasionen verhindert, da keine Kosten-Nutzen-Analyse von Managementmaßnahmen abgeleitet werden kann. Um die wirtschaftlichen Kosten von Invasionen in Deutschland, einem mitteleuropäischen Land mit dem viertgrößten BIP der Welt, zu ermitteln, haben wir veröffentlichte Daten analysiert, die aus der ersten globalen Bewertung der wirtschaftlichen Kosten invasiver gebietsfremder Arten stammen. Insgesamt wurden die wirtschaftlichen Kosten zwischen 1960 und 2020 auf 9.8 Milliarden US-Dollar geschätzt, einschließlich potenzieller Kosten in Höhe von 8.9 Milliarden US-Dollar. Die potenziellen Kosten waren hauptsächlich auf die extrapolierten Kosten des amerikanischen Ochsenfrosches Lithobates catesbeianus, der Tollkirsche Prunus serotina und zweier Säugetiere zurückzuführen: des Bisamratten Ondatra zibethicus und des amerikanischen Nerz Neovison vison. Die beobachteten Kosten wurden von einer breiten Palette von Taxa getrieben und waren hauptsächlich mit kontrollbezogenen Ausgaben und Ressourcenschäden oder -verlusten verbunden. Wir haben einen erheblichen Anstieg der Kosten im Vergleich zu früheren Schätzungen und im Laufe der Zeit festgestellt. Wichtig ist, dass von den in Deutschland gemeldeten 2.249 gebietsfremden und 181 invasiven Arten nur 28 Arten wirtschaftliche Kosten verzeichneten. Daher sollte die Gesamtquantifizierung der Kosten invasiver Arten hier als sehr konservativ angesehen werden. Unsere Ergebnisse zeigen einen deutlichen Mangel an Informationen in der öffentlich zugänglichen Literatur und in staatlichen Quellen zu Invasionskosten auf nationaler Ebene, was die höchstwahrscheinliche Existenz viel höherer Invasionskosten in Deutschland maskiert. Angesichts der steigenden Invasionsraten werden die wirtschaftlichen Kosten voraussichtlich weiter steigen. Die Bewertung und Berichterstattung der wirtschaftlichen Kosten muss verbessert werden, um eine Grundlage für eine wirksame Eindämmung und Bewältigung der Invasionen in die nationale und internationale Wirtschaft zu schaffen. Costos económicos de las especies invasoras en Alemania. Las especies invasoras representan una conocida amenaza en general para la biodiversidad del planeta y el bienestar humano. A menudo se omite la cuantificación de los costes económicos que provocan las especies invasoras, a pesar de los impactos sustanciales que ellas provocan. En consecuencia, el reparto de los recursos para el manejo de las respuestas es inadecuado ante las invasiones, por lo tanto no es posible obtener un análisis de los costos y beneficios de las acciones de manejo. Para determinar los costos económicos de las invasiones en Alemania, un país Centroeuropeo con el 4to producto interno bruto más grande del planeta, se analizaron datos publicados en la primera evaluación global de los costes económicos de especies invasoras. En general se estimaron costes económicos de US $9.8 mil millones entre los años 1960 y 2020, incluyendo US $8.9 mil millones en costos potenciales. Los costos potenciales se asociaron con los costes extrapolados de la rana toro americana Lithobates catesbeianus, el cerezo negro Prunus serotina y dos mamíferos: la rata almizclera Ondatra zibethicus y el visón americano Neovison vison. Los costes observados se condujeron entre una amplia variedad de taxa de los cuales la mayoría se asociaron con gastos relacionados con el control de las especies y daños a los recursos o pérdidas relacionadas con invasiones. Se identificó un incremento considerable de los costes relacionados con estimaciones previas y a través del tiempo. De manera importante, de las 2,249 especies exóticas y 181 especies invasoras, solo se han reportado costes de 28 especies invasoras en Alemania. Por lo tanto, el total de los costes cuantificados de las especies invasoras que se presentan aquí deben de mostrarse como muy moderados. Se destaca una ausencia de información entre la literatura de acceso libre y las fuentes gubernamentales sobre los costes de las invasiones s a nivel nacional, enmascarando así la alta probabilidad de que existan mayores costes por invasiones en Alemania. Adicionalmente, dado que la tasa de invasión se encuentra en incremento, se espera que los costes económicos sufran un incremento. Se requiere mejorar la evaluación y el reporte de los costes económicos para sentar un adecuado precedente para la mitigación y manejo efectivo de las invasiones en la economía nacional e internacional. Ekonomické náklady na invazivní druhy v Německu. Nepůvodní invazní druhy jsou dobře známou a všudypřítomnou hrozbou pro celosvětovou biodiversitu i blahobyt člověka. Navzdory podstatným dopadům biologických invazí však často postrádáme přehled o jejich nákladovosti pro národní ekonomiky. V důsledku toho byla omezena i adekvátní alokace zdrojů pro management biologických invazí, jelikož nebylo možné vypracovat analýzu nákladů a přínosů takových akcí. Cílem této studie bylo pomocí speciálně vytvořené databáze zhodnotit náklady způsobené invazními druhy v Německu, které je čtvrtou zemí s nejvyšším HDP na světě. Celkově byly ekonomické náklady invazních druhů mezi lety 1960 a 2020 odhadnuty na 9.8 miliardy amerických dolarů. Jednalo se především o potenciální odhadnuté náklady způsobené severoamerickým skokanem volským Lithobates catesbeianus, střemchou pozdní Prunus serotina a dvěma savci – ondatrou pižmovou Ondatra zibethicus a norkem americký Neovison vison. Pozorované náklady byla způsobené různými skupinami organismů a většinou byly spojeny s kontrolou jejich šíření a jimi způsobenými škodami. V průběhu času bylo oproti dřívějším odhadům zaznamenáno značné zvýšení těchto ekonomických škod. V Německu žije 2249 nepůvodních organismů, z nichž je 181 považováno za invazní, avšak pouze u 28 existují ekonomicky vyčíslené škody. Reálná výše těchto škod je tedy očekávatelně podstatně vyšší. Tato zjištění poukazují na značný nedostatek takových údajů v dosažitelných informačních zdrojích, jenž velmi pravděpodobně maskuje existenci podstatně vyšších škod způsobených invazními druhy v Německu. Jelikož počet invazních druhů v zemi roste, lze do budoucna očekávat i růst jimi způsobených škod. Je tedy potřeba zlepšit hodnocení a vykazování ekonomických nákladů souvisejících s invazními druhy, aby bylo možné vytvořit podmínky pro jejich eliminaci a management na národní i mezinárodní úrovni. Coûts économiques des espèces envahissantes en Allemagne. Les espèces exotiques envahissantes sont une menace bien connue et omniprésente pour la biodiversité mondiale et le bien-être humain. Malgré les connaissances sur les impacts substantiels de ces espèces, les synthèses quantitatives des coûts monétaires induits par les invasions sur les économies nationales font souvent défaut. De fait, le rapport coûts-avantages des mesures de gestion des invasions biologiques est souvent difficile à obtenir. Cela a nécessairement des conséquences négatives sur l’allocation adéquate de ressources dédiées à ces mesures et actions destinées à prévenir ou contrôler les espèces exotiques envahissantes. Pour déterminer le coût économique des invasions en Allemagne (pays européen avec le quatrième PIB le plus important au monde), nous avons analysé les données publiées collectées à partir de la première compilation mondiale des coûts économiques des espèces exotiques envahissantes. Dans l'ensemble, les coûts économiques ont été estimés à 9,8 milliards de dollars entre 1960 et 2020, dont 8,9 milliards de dollars de coûts potentiels. Les coûts potentiels étaient principalement liés aux coûts extrapolés du ouaouaron d'Amérique Lithobates catesbeianus, du cerisier noir Prunus serotina et de deux mammifères: le rat musqué Ondatra zibethicus et le vison d'Amérique Neovison vison. Les coûts observés étaient attribuables à un large éventail de taxons et principalement associés aux dépenses liées au contrôle et aux dommages ou pertes affectant les ressources humaines. Nous avons identifié une augmentation considérable des coûts au cours du temps, avec des coûts supérieurs aux estimations réalisées précédemment. Il est important de noter que sur les 2249 espèces exotiques et 181 espèces envahissantes signalées en Allemagne, seules 28 espèces ont des coûts économiques reportés dans la base de données considérée. Par conséquent, les coûts quantifiés ici doivent être interprétés avec prudence. Nos résultats mettent donc en évidence un manque flagrant d'informations dans la littérature librement accessible et les sources gouvernementales sur les coûts des invasions au niveau national, masquant l'existence hautement probable de coûts beaucoup plus élevés en Allemagne. De plus, il ne fait aucun doute que l’augmentation toujours croissante des phénomènes d'invasion biologique sera liée à l’augmentation concomitante des coûts économiques associés. L'évaluation et la communication des coûts économiques doivent nécessairement être améliorées pour contribuer à l’établissement et l’implémentation de mesures de gestion efficaces des invasions aux échelles nationale et internationale.

Highlights: • Predators displayed a Type II functional response towards prey • Microplastics had no effect on predator feeding efficiency • Functional responses are a useful tool for microplastic exposure studies • An environmentally relevant approach is needed in future microplastic exposure studies Abstract: Microplastics may affect the physiology, behaviour and populations of aquatic and terrestrial fauna through many mechanisms, such as direct consumption and sensory disruption. However, the majority of experimental studies have employed questionably high dosages of microplastics that have little environmental relevance. Predation, in particular, is a key trophic interaction that structures populations and communities and influences ecosystem functioning, but rarely features in microplastic research. Here, we quantify the effects of low (~65-114 MP/L) and high (~650-1140 MP/L) microplastic concentrations on the feeding behaviour of a ubiquitous and globally representative key marine predator, the shore crab, Carcinus maenas. We used a functional response approach (predator consumption across prey densities) to determine crab consumption rates towards a key marine community prey species, the blue mussel Mytilus edulis, under low and high microplastic concentrations with acute (8h) and chronic (120 h) microplastic exposure times. For both the acute and chronic microplastic exposure experiments, proportional prey consumption by crabs did not differ with respect to microplastic concentration, but significantly decreased over increasing prey densities. The crabs thus displayed classical, hyperbolic Type II functional responses in all experimental groups, characterised by high consumption rates at low prey densities. Crab attack rates, handling times and maximum feeding rates (ie functional response curves) were not significantly altered under lower or higher microplastics concentrations, or by acute or chronic microplastic exposures. Here, we show that functional response analyses could be widely employed to ascertain microplastic impacts on consumer-resource interactions. Furthermore, we suggest that future studies should adopt both acute and chronic microplastic exposure regimes, using environmentally-relevant microplastic dosages and types as well as elevated future scenarios of microplastic concentrations.

Invasive fishes continue to adversely impact the structure and function of aquatic ecosystems globally. The effects of introduced populations may, however, differ according to key characteristics such as size, abundance, invaded habitat type, and community composition. Here, we conduct diet analyses to describe the feeding characteristics of the nonnative North American Pumpkinseed, Lepomis gibbosus, across multiple habitat types (three lentic and three lotic systems) and fish size classes. Pumpkinseeds exhibited a broad diet, inclusive of numerous threatened species groups (e.g., amphibians) and commonly included dipterans and detritus overall. Observed diets were more diverse in ponds compared to stream habitats, as well as for larger individuals, with individuals in streams tending to consume terrestrial insects in higher numbers. Our results show that the impact of Lepomis gibbosus differs not only according to size and ontogeny, but also depending on the habitat type, probably due to different prey availabilities and biotic interactions. This has implications for ecological impacts of this invasive species in lentic and lotic systems, with a generalist diet potentially facilitating impacts on a broad range of prey taxa, with concomitant adverse competitive effects on native predator species.

Biodiversity is declining on a global scale and the spread of invasive alien species (IAS) is a major driver, particularly through predatory impacts. Thus, effective means of assessing and predicting the consequences of IAS predation on native prey population stability remains a vital goal for conservation. Here, we applied two classic ecological concepts, consumer functional response (FR) and prey switching, to predict and understand the ecological impacts of juveniles of the lionfish (Pterois volitans), a notorious and widespread marine invader. Functional responses and prey switching propensities were quantified towards three representative prey species:Artemia salina,Palaemonetes varians, andGammarus oceanicus. Lionfish exhibited potentially destabilising Type II FRs towards individual prey species, owing to high consumption rates at low prey densities, whilst FR magnitudes differed among prey species. Functional response attack rates (a) were highest, and handling times (h) lowest, towardsA. salina, followed byP. variansand thenG. oceanicus. Maximum feeding rates (1/h) and functional response ratios (FRR;a/h) also followed this impact gradient for the three prey species. Lionfish, however, displayed a potentially population stabilising prey switching propensity (i.e. frequency-dependent predation) when multiple prey species were presented simultaneously, where disproportionately less of rare prey, and more of abundant prey, were consumed. Whilst FR and FRR magnitudes indicate markedper capitalionfish predatory impacts towards prey species, a strong prey switching propensity may reduce in-field impacts by offering low density prey refuge in biodiverse communities. Our results thus corroborate field patterns documenting variable impacts of lionfish, with prey extirpations less likely in diverse communities owing to frequency-dependent predation.

Predation is a critical ecological process that directly and indirectly mediates population stabilities, as well as ecosystem structure and function. The strength of interactions between predators and prey may be mediated by multiple density dependences concerning numbers of predators and prey. In temporary wetland ecosystems in particular, fluctuating water volumes may alter predation rates through differing search space and prey encounter rates. Using a functional response approach, we examined the influence of predator and prey densities on interaction strengths of the temporary pond specialist copepod Lovenula raynerae preying on cladoceran prey, Daphnia pulex, under contrasting water volumes. Further, using a population dynamic modeling approach, we quantified multiple predator effects across differences in prey density and water volume. Predators exhibited type II functional responses under both water volumes, with significant antagonistic multiple predator effects (i.e., antagonisms) exhibited overall. The strengths of antagonistic interactions were, however, enhanced under reduced water volumes and at intermediate prey densities. These findings indicate important biotic and abiotic contexts that mediate predator–prey dynamics, whereby multiple predator effects are contingent on both prey density and search area characteristics. In particular, reduced search areas (i.e., water volumes) under intermediate prey densities could enhance antagonisms by heightening predator–predator interference effects., Predator and prey densities are variable spatiotemporally across all habitat types globally. Our results indicate that predatory interaction strengths differ depending on densities of both predator and prey participants, with antagonistic multiple predator effects enhanced at intermediate prey densities. Future habitat changes resulting from anthropogenic activity that alter communities could have marked implications for trophic dynamics.

Predation shapes community structures via direct and indirect mechanisms and it is an ecological imperative that predatory impacts are predicted. In this study, we used comparative functional responses (FRs) to compare resource utilisation (i.e. per capita effects) between young-of-year Largemouth Bass and Florida Bass across different temperatures treatments (18, 24 and 30 °C). Culex mosquito larvae were used as prey during the experiments. Across all temperature treatments, Type II FRs were observed, which could cause population-destabilising pressures towards native prey communities due to high predation rates at low prey densities. Attack rates did not differ significantly between the fish species at either temperature. Handling times of Largemouth Bass increased significantly with temperature, whilst the converse was true for Florida Bass. Largemouth Bass were found to have higher maximum feeding rates at the low temperature (18 °C), driven by significantly shorter handling times compared to Florida Bass. At the intermediate temperature (24 °C), handling times and thus maximum feeding rates did not differ significantly between the two species. At high temperature (30 °C) Florida Bass exhibited a significantly higher maximum feeding rate and shorter handling time than Largemouth Bass. These results suggest that temperature drives differential ecological impacts, with Florida Bass exerting higher impact than Largemouth Bass on prey at high temperatures and Largemouth Bass having higher impacts than Florida Bass at lower temperatures.

Urbanization has caused an increase in favorable habitats for Aedes aegypti (Diptera: Culicidae), given their ability to reproduce in small and often non-degradable artificial water-containers. While much work has been done on Ae. aegypti biology and ecology in urban landscapes, the role of shading on immature stages as an independent factor from temperature, and any possible interactions between these factors, remains unexamined. We assessed how temperature and shading affected egg hatch-rate, larval/pupal mortality, and larval development to adult stage under different factorial temperature (28; 31; 34; 37; 40° C) and shade (0%, 3,100 lux; 40%, 1,860 lux; 75%, 775 lux; 100%, 0 lux) regimes. Hatch-rate was significantly lower at 37° C (57 %), and no eggs hatched at 40° C. There was no significant effect caused by shading on hatchability. Larval and pupal mortality at 37° C was significantly higher (35%) compared to lower temperature groups, while the effects of shading were emergent at low temperatures. Developmental times from hatching to adult emergence were significantly reduced with increasing temperatures and with greater light exposures. The eco-physiological response of Ae. aegypti larvae to temperature and light regimes suggest a photosensitivity previously unstudied in this species.

Mosquito-borne disease incidences continue to proliferate and cause enormous mortality and debilitation rates. Predatory natural enemies can be effective in population management strategies targeting medically-important mosquito species. However, context-dependencies and target organism behavioural responses can impede or facilitate biological control agents. Black pond dye has been shown to be a strong mosquito oviposition attractant, and could potentially be used alongside predatory agents to create mosquito population sink effects. Here, we thus examine the predatory impact of larvae of the non-biting chaoborid midge Chaoborus flavicans towards larvae of the West Nile virus vector mosquito complex Culex pipiens in the presence and absence of black pond dye. We then examine the ovipositional responses of C. pipiens to predation risk and dye in laboratory-, semi-field- and field-based trials. Larval C. flavicans exhibited potentially population destabilising type II functional responses towards mosquito larvae irrespective of the presence of pond dye. Neither consumption rates nor functional response parameters (attack rates, handling times) were significantly influenced by the presence of dye, indicating a use of hydromechanics to detect mosquito prey by chaoborids. Wild-caught adult C. pipiens did not avoid predatory chaoborids when ovipositing, however they were significantly more attracted to oviposit in dye-treated water regardless of the presence of predators. We thus demonstrate high predatory impact towards mosquito larvae by non-biting chaoborid midges during their predaceous aquatic larval stages, and proliferations of such predators may assist or augment control efforts for mosquitoes. Our results suggest a lack of influence of predatory dipterans on oviposition selectivity by C. pipiens mosquitoes, and that pond dye may enhance the efficacy of select predatory biological control agents through the creation of population sinks, characterised by high rates of oviposition and subsequent predation.

In tomato, Ve1 gene expression is induced specifically by physical damage or plant wounding, resulting in a defense/stress cascade that mimics responses during Verticillium colonization and wilt. In tomato, Verticillium resistance is determined by the Ve gene locus, which encodes two leucine-rich repeat-receptor-like proteins (Ve1, Ve2); the Ve1 gene is induced differentially while Ve2 is constitutively expressed throughout disease development. These profiles have been observed even during compatible Verticillium interactions, colonization by some bacterial pathogens, and growth of transgenic tomato plants expressing the fungal Ave1 effector, suggesting broader roles in disease and/or stress. Here, we have examined further Ve gene expression in resistant and susceptible plants under abiotic stress, including a water deficit, salinity and physical damage. Using both quantitative RT-PCR and label-free LC–MS methods, changes have been evaluated at both the mRNA and protein levels. The results indicate that Ve1 gene expression responds specifically to physical damage or plant wounding, resulting in a defense/stress cascade that resembles observations during Verticillium colonization. In addition, the elimination or reduction of Ve1 or Ve2 gene function also result in proteomic responses that occur with wilt pathogen and continue to be consistent with an antagonistic relationship between the two genes. Mutational analyses also indicate the plant wounding hormone, systemin, is not required, while jasmonic acid again appears to play a direct role in induction of the Ve1 gene.

Recent studies have highlighted an important role of structural variation (SV) in ecological and evolutionary processes, but few have studied nonmodel species in the wild. As part of our long-term research programme on the nonmodel teleost fish Australasian snapper (Chrysophrys auratus), we aim to build one of the first catalogues of genomic variants (SNPs and indels, and deletions, duplications and inversions) in fishes and evaluate overlap of genomic variants with regions under putative selection (Tajima's D and π), and coding sequences (genes). For this, we analysed six males and six females from three locations in New Zealand and generated a high-resolution genomic variation catalogue. We characterized 20,385 SVs and found they intersected with almost a third of all annotated genes. Together with small indels, SVs account for three times more variation in the genome in terms of bases affected compared to SNPs. We found that a sizeable portion of detected SVs was in the upper and lower genomic regions of Tajima's D and π, indicating that some of these have an effect on the phenotype. Together, these results shed light on the often neglected genomic variation that is produced by SVs and highlights the need to go beyond the mere measure of SNPs when investigating evolutionary processes, such as species diversification and adaptation.

Dipeptidyl peptidase-4 inhibitors (DPP4i) are a class of orally available, small molecule inhibitors for the management of Type-II diabetes. A rapid, real-time, functional breath test for DPP4 enzyme activity could help to define DPP4i efficacy in patients that are refractory to treatment. We aimed to develop a selective, non-invasive, stable-isotope 13C-breath test for DPP4. In vitro experiments were performed using high (Caco-2) and low (HeLa) DPP4 expressing cells. DPP gene expression was determined in cell lines by qRT-PCR. A DPP4 selective 13C-tripeptide was added to cells in the presence and absence of the DPP4 inhibitor Sitagliptin. Gas samples were collected from the cell headspace and 13CO2 content quantified by isotope ratio mass spectrometry (IRMS). DPP4 was highly expressed in Caco-2 cells compared to HeLa cells and using the 13C-tripeptide, we detected a high 13CO2 signal from Caco2 cells. Addition of Sitaglitpin to Caco2 cells significantly inhibited this 13CO2 signal. 13C-assay DPP4 activity correlated positively with the enzyme activity detected using a colorimetric substrate. We have developed a selective, non-invasive, 13C-assay for DPP4 that could have broad translational applications in diabetes and gastrointestinal disease.

Aquatic invasive species (AIS) continue to adversely influence freshwater ecosystems worldwide. Management protocols designed to prevent further invader spread are essential, as control and eradication of established AIS populations are often complex, costly, resource-intensive, and can be relatively ineffective. Therefore, in-field biosecurity techniques designed to deliver effective decontamination of water users’ equipment, e.g. angler’s nets, footwear, and kayaks, are needed. Disinfection through brief submergence in chemical solutions may be beneficial. Although broad-spectrum, aquatic disinfectants have been recommended as suitable biosecurity agents, the ability of these chemicals to inhibit invader spread remains poorly understood. Here, we examined the effectiveness of two aquatic disinfectants, Virasure® Aquatic and Virkon® Aquatic, to reduce growth rates, induce biodegradation, and decrease shoot and root production at the fragmentary propagule stage of the prolific invasive macrophyte, Elodea nuttallii (Planchon) H. St. John, 1920. We examined the efficacy of both chemicals at submergence times of one, two and five minutes, using 0% (0 g L−1), 1% (10 g L−1) and 4% (40 g L−1) disinfectant solutions. Both apical and mid-stem fragmentary sections were examined separately. A biodegradation scale was applied to visually assess tissue degradation and/or resumption of growth. Although E. nuttallii displayed substantial and sustained degradation after all disinfection treatments, all fragments demonstrated viability through resumption of shoot or root growth over the observation period. Therefore, at the examined concentrations and exposure times, it appears that these broad-spectrum aquatic disinfectants are not capable of curtailing the spread of invasive E. nuttallii. However, longer submergence times, multiple applications and synergistic effects of different biosecurity treatments could potentially prevent further E. nuttallii spread and this requires investigation.

Microplastics (MPs) continue to proliferate and pollute aquatic and terrestrial environments globally. The impacts of MP pollution on ecosystems and their functioning remain poorly quantified, with most research hitherto focusing on marine ecosystems. There is a paucity of information on the impacts of MPs in freshwater ecosystems, despite the broad range of pathways through which MPs can proliferate and the extensive range of species which actively ingest MPs in these systems. Of particular interest are organisms that bridge aquatic and terrestrial habitats. The present study thus examines the uptake, ontogenic transference and effect of different concentrations (0, 50, 100 and 200 MPs mL-1) and sizes (2 and 15 µm) concentrations and sizes of polystyrene MPs between aquatic and terrestrial life stages of Culex pipiens complex mosquitoes. Both 2 and 15 µm MPs transferred from the aquatic larval to terrestrial adult stage of Culex mosquitoes, and uptake correlated tightly with initial exposure concentration. However, neither concentration nor size of MPs significantly influenced mortality rates between the aquatic larval and terrestrial adult stage. There was also no impact of MPs on the weight of emerging mosquito adults. We thus demonstrate that MPs can be transferred ontogenically through organisms with complex life histories, presenting a potential pathway for dispersal of MPs into terrestrial environments. We also show that MPs exposure does not affect mortality rates between life stages of freshwater Culex populations. This suggests that MPs do not impact nutritional uptakes, with unhampered development to adulthood facilitating subsequent dispersal of MPs aerially and between freshwater and terrestrial habitats.

Commercially grown kiwifruit (genus Actinidia) are generally of two sub-species which have a base haploid genome of 29 chromosomes. The yellow-fleshed Actinidia chinensis var. chinensis, is either diploid (2n = 2x = 58) or tetraploid (2n = 4x = 116) and the green-fleshed cultivar A. chinensis var. deliciosa “Hayward,” is hexaploid (2n = 6x = 174). Advances in breeding green kiwifruit could be greatly sped up by the use of molecular resources for more efficient and faster selection, for example using marker-assisted selection (MAS). The key genetic marker that has been implemented for MAS in hexaploid kiwifruit is for gender testing. The limited marker-trait association has been reported for other polyploid kiwifruit for fruit and production traits. We have constructed a high-density linkage map for hexaploid green kiwifruit using genotyping-by-sequence (GBS). The linkage map obtained consists of 3686 and 3940 markers organized in 183 and 176 linkage groups for the female and male parents, respectively. Both parental linkage maps are co-linear with the A. chinensis “Red5” reference genome of kiwifruit. The linkage map was then used for quantitative trait locus (QTL) mapping, and successfully identified QTLs for king flower number, fruit number and weight, dry matter accumulation, and storage firmness. These are the first QTLs to be reported and discovered for complex traits in hexaploid kiwifruit.

© Crown 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871081 (AQUACOSM) as well as financial support from the Regional Council of Ile-de-France under the DIM Program R2DS I-05-098/R and 2015-1657. It has received a support under the French program ‘‘Investissements d’Avenir’’ with the references ANR-10-EQPX-13-01 Planaqua and ANR-11-INBS-0001 AnaEE France. It has benefited from technical and human resources provided by CEREEP Ecotron IleDeFrance (CNRS/ENS UMS 3194), with JWED also supported by Inland Fisheries Ireland (IFI), RNC by the Alexander von Humboldt Foundation and Department for the Economy Northern Ireland, and NEC by Environmental Protection Agency (EPA). PRL thanks the Canada Research Chair program. Thanks also to the Natural Environment Research Council (NERC). Faculty yes

Suppression of established populations of invasive alien species can be a complex and expensive process, which is frequently unsuccessful. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high impact invader that can adversely alter freshwater ecosystems and decrease their socioeconomic value. To date, C. fluminea continues to spread and persist within freshwater environments worldwide, despite repeated management attempts to prevent dispersal and suppress established populations. As extensive C. fluminea beds can often become exposed during low-water conditions, the direct application of hot or cold thermal shock treatments has been proposed as suitable mechanism for their control. Further, mechanical substrate disturbance may enhance the efficacy of thermal shock treatments by facilitating exposures to multiple layers of buried clams. In the present study, we advanced these methods by assessing combined applications of both hot and cold thermal shock treatments for control of C. fluminea, using steam spray (≥100 °C; 350 kPa), low- or high-intensity open-flame burns (~1000 °C) and dry ice (−78 °C). In a direct comparison of raking combined with hot thermal shock applications, both steam and high-intensity open-flame treatments tended to be most effective, especially following multiple applications. In addition, when hot thermal treatments are followed by a final cold shock (i.e. dry ice), steam treatments tended to be most effective. Further, when dry ice was applied either alone or prior to an application of a hot shock treatment, substantial if not complete C. fluminea mortality was observed. Overall, this study demonstrated that combined applications of hot and cold thermal shock treatments, applied following the disruption of the substrate, can substantially increase C. fluminea mortality compared to separate hot or cold treatments.

The Ve-resistance locus in tomato acts as a resilience gene by affecting both the stress/defense cascade and growth, constituting a signaling intercept with a competitive regulatory mechanism. For decades, the tomato Ve-gene has been recognized as a classical resistance R-gene, inherited as a dominant Mendelian trait and encoding a receptor protein that binds with a fungal effector to provide defense against Verticillium dahliae and V. albo-atrum. However, recent molecular studies suggest that the function and role(s) of the Ve-locus and the two proteins that it encodes are more complex than previously understood. This review summarizes both the background and recent molecular evidence and provides a reinterpretation of the function and role(s) of the Ve1- and Ve2-genes and proteins that better accommodates existing data. It is proposed that these two plasma membrane proteins interact to form a signaling intercept that directly links defense and growth. The induction of Ve1 by infection or wounding promotes growth but also downregulates Ve2 signaling, resulting in a decreased biosynthesis of PR proteins. In this context, the Ve1 R-gene acts as a Resilience gene rather than a Resistance gene, promoting taller more robust tomato plants with reduced symptoms (biotic and abiotic) and Verticillium concentration.

Biosecurity protocols designed to prevent the spread of invasive alien species (IAS) are now an essential aspect of IAS management. However, the effectiveness of various biosecurity treatments requires further exploration. Killer shrimp, Dikerogammarus villosus, a notoriously high impact and ecosystem destabilising invader, has rapidly spread across Europe, and is of concern to invade Northern America. In this study, we examine the effectiveness of three commonly used, broad-spectrum disinfectants to cause mortality of D. villosus: Virasure Aquatic, Virkon Aquatic, and Virkon S. Immersion and spray treatments of 1%, 2% and 4% disinfectant solutions were examined for applications of up to 300 secs immersion and for up to ten consecutive sprays. Furthermore, we assessed the effectiveness of steam (≥100 °C) treatments for up to 120 secs. For all disinfectants, immersion in 1% solutions caused 100% mortality at ≥120 secs. At higher concentrations, shorter immersion times caused complete mortality: 60 and 15 secs for 2% and 4% solutions, respectively. Five sprays of 2% and 4% solutions resulted in 100% mortality, for all disinfectants. Direct steam exposure was highly effective, with complete D. villosus mortality occurring at ≥10 secs. Overall, brief exposure to broad-spectrum disinfectants and direct steam could be used to limit D. villosus spread.

Leaf litter contributes to the functioning of aquatic ecosystems through allochthonous inputs of carbon, nitrogen, and other elements. Here, we examine leaf litter nutrient inputs and decomposition associated with four plant species using a mesocosm approach. Native sycamore fig Ficus sycomorus L., and silver cluster&ndash, leaf Terminalia sericea Burch. ex DC. decomposition dynamics were compared to invasive tickberry Lantana camara L. and guava Psidium guajava L., whereby phosphate, nitrate, nitrite, silicate, and ammonium releases were quantified over time. Leaf inputs significantly reduced pH, with reductions most marked by invasive L. camara. Conductivity was heightened by all leaf input treatments, except native T. sericea. Leaf inputs significantly affected all nutrient levels monitored in the water over time, except for silicate. In particular, leaf litter from invasive L. camara drove significantly increased nutrient concentrations compared to other native plant species, whilst effects of invasive P. guajava were less statistically clear. The end weights of the leaf litter demonstrated decomposition differences among the species types, following a decreasing order of P. guajava &gt, T. sericea &gt, F. sycomorus &gt, L. camara, further suggesting high organic inputs from invasive L. camara. The study results highlight that differential leaf litter decomposition rates of four plant species can play a significant role in nutrient release, in turn altering aquatic ecosystem productivity. However, these effects likely depend on species-specific differences, rather than between invasive&ndash, native species generally. Shifting terrestrial plant communities may alter aquatic community composition, but specific effects are likely associated with leaf traits.

Highlights: • Thermal biology of rock-pool and pan specialist branchiopods were contrasted. • Wetland type was not a good predictor of branchiopod thermal preference/limits. • Spinicaudatans preferring higher temperatures than anostracans. • Spinicaudatans were more tolerant of high temperatures than anostracans. • Anostracans may be more susceptible to projected climatic warming. Abstract: Large branchiopods are specialist crustaceans adapted for life in temporary, thermally dynamic wetland ecosystems. Certain large branchiopod species are, however, restricted to specific temporary wetland types, exemplified by their physico-chemical and hydroperiod characteristics. Here, we contrasted the thermal preference and critical thermal maxima (CTmax) and minima (CTmin) of southern African anostracans and spinicaudatans found exclusively in either temporary rock-pool or pan wetland types. We hypothesized that environment of origin would be a good predictor of thermal preference and critical thermal limits. To test this, Branchiopodopsis tridens (Anostraca) and Leptestheria brevirostris (Spinicaudata) were collected from rock-pool habitats, while Streptocephalus cafer (Anostraca) and a Gondwanalimnadia sp. (Spinicaudata) were collected from pan habitats. In contrast to our hypothesis, taxonomic relatedness was a better predictor of CTmax and temperature preference than environment of origin. Spinicaudatans were significantly more tolerant of high temperatures than anostracans, with L. brevirostris and Gondwanalimnadia sp. median CTmax values of 45.1 °C and 44.1 °C, respectively, followed by S. cafer (42.8 °C) and B. tridens (41.4 °C). Neither environment or taxonomic relatedness were good predictors of CTmin trends, with B. tridens (0.9 °C) and Gondwanalimnadia sp. (2.1 °C) having the lowest median CTmin values, followed by L. brevirostris (3.4 °C) and S. cafer (3.6 °C). On the contrary, temperature preferences differed according to taxa, with spinicaudatans significantly preferring higher temperatures than anostracans. Leptestheria brevirostris and Gondwanalimnadia sp. both spent most time at temperatures 30–32 °C, S. cafer at 18–20 °C and B. tridens at 21–23 °C. Constrained thermal traits reported here suggest that the studied anostracans might be more susceptible to projected climatic warming than the spinicaudatans, irrespective of habitat type, however, these taxa may also compensate through phenotypic plasticity.

Lake and reservoir ecosystems are regarded as heterotrophic detritus-based habitats which are dependent on both autochthonous and allochthonous organic matter for the majority of energy inputs. In particular, allochthonous detritus is in particular important for the trophic dynamics of microbial organisms, macroinvertebrates and benthic plants in freshwaters. Here, we assess macroinvertebrate colonisation, and quantify decomposition rates, of leaf litter from species of native and invasive plants in a small agricultural reservoir. Native fig Ficus sycomorus and silver cluster–leaf Terminalia sericea were compared to invasive tickberry Lantana camara and guava Psidium guajava, whereby macroinvertebrate colonisation was assessed over time. Leaf treatments had a significant, group-specific effect on abundances and composition among focal macroinvertebrates. Invasive leaves reduced Physidae and Oligochaeta abundances, yet Ostracoda were significantly more abundant in the presence of invasive P. guajava. Chironomidae relative abundances increased under invasive L. camara treatments, whilst differences among leaf treatment effects on Coenogrionidae abundances were not statistically clear. In turn, macroinvertebrate diversity did not differ significantly among plant treatment groups. The decomposition rate of the leaf litter demonstrated differences among the species, following a decreasing order of L. camara > F. sycomorus > T. sericea > P. guajava. The study results highlight that leaf litter species identity among invasive and native plants plays an important role in the colonisation of macroinvertebrates in small reservoirs, thereby differentially supporting aquatic environments and food webs. However, differences were not uniform across invader-native groupings. Nonetheless, certain invasive leaf litter decomposes faster than native litter, with possible implications for broader nutrient dynamics and subsequent community composition.

Control strategies for established populations of invasive alien species can be costly and complex endeavours, which are frequently unsuccessful. Therefore, rapid-reaction techniques that are capable of maximising efficacy whilst minimising environmental damage are urgently required. The Asian clam (Corbicula fluminea Müller, 1774), and the zebra mussel (Dreissena polymorpha Pallas, 1771), are invaders capable of adversely affecting the functioning and biodiversity of freshwater ecosystems. Despite efforts to implement substantial population-control measures, both species continue to spread and persist within freshwater environments. As bivalve beds often become exposed during low-water conditions, this study examined the efficacy of steam-spray (≥100 °C, 350 kPa) and open-flame burn treatments (~1000 °C) to kill exposed individuals. Direct steam exposure lasting for 5 min caused 100% mortality of C. fluminea buried at a depth of 3 cm. Further, combined rake and thermal shock treatments, whereby the substrate is disturbed between each application of either a steam or open flame, caused 100% mortality of C. fluminea specimens residing within a 4-cm deep substrate patch, following three consecutive treatment applications. However, deeper 8-cm patches and water-saturated substrate reduced maximum bivalve species mortality rates to 77% and 70%, respectively. Finally, 100% of D. polymorpha specimens were killed following exposure to steam and open-flame treatments lasting for 30 s and 5 s, respectively. Overall, our results confirm the efficacy of thermal shock treatments as a potential tool for substantial control of low-water-exposed bivalves. Although promising, our results require validation through upscaling to field application, with consideration of other substrate types, increased substrate depth, greater bivalve densities, non-target and long-term treatment effects.

The direct effects of temperature increases and differences among life-history might affect the impacts of native and invasive predators on recipient communities. Comparisons of functional responses can improve our understanding of underlying processes involved in altering species interaction strengths and may predict the effect of species invading new communities. Therefore, we investigated the functional responses of the mourning gecko Lepidodactylus lugubris (Duméril & Bibron, 1836) to explore how temperature, body-size and prey density alter gecko predatory impacts in ecosystems. We quantified the functional responses of juvenile and adult geckos in single-predator experiments at 20, 23 and 26 °C. Both displayed saturating Type-II functional responses, but juvenile functional responses and the novel Functional Response Ratio were positively affected by temperature as juvenile attack rates (a) increased as a function of increased temperature. Handling times (h) tended to shorten at higher temperature for both predator stages. We demonstrate that the effects of temperature on functional responses of geckos differ across ontogeny, perhaps reflecting life-history stages prioritising growth and maturation or body maintenance. This indicates that temperature-dependent gecko predatory impacts will be mediated by population demographics. We advocate further comparisons of functional responses to understand the invasiveness and future predatory impacts of geckos, and other invasive species globally, as temperatures change.

The Ve-resistance locus in tomato and potato affects both stress/defense and growth, consistent with a signaling intercept and a competitive regulatory mechanism. Acting in an antagonistic fashion, the two genes comprising the tomato Ve-resistance locus have been shown to influence both the defense/stress cascade, which causes wilt symptoms, and plant growth (Nazar et al. in Planta 247:1339-1350, 2018c); in contrast, both have been reported to elevate wilt resistance in potato or Arabidopsis. In a further examination of this influence in potato transformed with the Ve1 gene, effects are again demonstrated with respect to both disease resistance and crop productivity consistent with the Ve locus being a signaling intercept and the antagonistic effects, previously observed in tomato. The results support a competitive model in which the tomato Ve1 and Ve2 proteins act to reduce the detrimental effects of the defense/stress cascade and energy transfers to the developing potato tubers.

Although reports have documented loss of species diversity and ecological services caused by stressful temperature changes that result from climate change, some species cope through behavioral compensation. As temperatures and magnitudes of temperature extremes increase, animals should compensate to maintain fitness (such as through temporary behavioral shifts in activity times). Appropriate timing of activity helps avoid competition across species. Although coprophagic dung beetles exhibit species-specific temporal activity times, it is unknown whether temperature drives evolution of these species-specific temporal activity times. Using nine dung beetle species (three each of diurnal, crepuscular, and nocturnal species), we explored differences in heat stress tolerance measured as critical thermal maxima (CTmax ; the highest temperature allowing activity) and heat knockdown time (HKDT; survival time under acute heat stress) across these species, and examined the results using a phylogenetically informed approach. Our results showed that day-active species had significantly higher CTmax (diurnal > crepuscular = nocturnal species), whereas crepuscular species had higher HKDT (crepuscular > nocturnal > diurnal species). There was no correlation between heat tolerance and body size across species with distinct temporal activity, and no significant phylogenetic constraint for activity. Species with higher CTmax did not necessarily have higher HKDT, which indicates that species may respond differently to diverse heat tolerance metrics. Acute heat tolerance for diurnal beetles indicates that this trait may constrain activity time and, under high acute temperatures with climate change, species may shift activity times in more benign environments. These results contribute to elucidate the evolution of foraging behavior and management of coprophagic beetle ecosystem services under changing environments.

Ireland, being an island situated on Europe’s western seaboard, has a fewer number of native species than mainland European Union Member States (MS). Increased numbers of vectors and pathways have reduced the island’s biotic isolation, increasing the risk of new introductions and their associated impacts on native biodiversity. It is likely that these risks are greater here than they are in continental MSs, where the native biodiversity is richer. A horizon scanning approach was used to identify the most likely invasive alien species (IAS) (with the potential to impact biodiversity) to arrive on the island of Ireland within the next ten years. To achieve this, we used a consensus-based approach, whereby expert opinion and discussion groups were utilised to establish and rank a list of 40 species of the most likely terrestrial, freshwater and marine IAS to arrive on the island of Ireland within the decade 2017–2027. The list of 40 included 18 freshwater, 15 terrestrial and seven marine IAS. Crustacean species (freshwater and marine) were taxonomically dominant (11 out of 40); this reflects their multiple pathways of introduction, their ability to act as ecosystem engineers and their resulting high impacts on biodiversity. Freshwater species dominated the top ten IAS (seven species out of ten), with the signal crayfish (Pacifastacus leniusculus) highlighted as the most likely species to arrive and establish in freshwaters, while roe deer (Capreolus capreolus) (second) and the warm-water barnacle (Hesperibalanus fallax) (fifth), were the most likely terrestrial and marine invaders. This evidence-based list provides important information to the relevant statutory agencies in both the Republic of Ireland and Northern Ireland to prioritise the prevention of the most likely invaders and aid in compliance with legislation, in particular the EU Regulation on Invasive Alien Species (EU 1143/2014). Targeted biosecurity in both jurisdictions is urgently required in order to manage the pathways and vectors of arrival, and is vital to maintaining native biodiversity on the island of Ireland.

Biosecurity protocols designed to prevent further spread of invasive alien species have become a key component of invader management strategies. Yet, the species-specific efficacy of many biosecurity treatments are frequently unclear or unknown. Invasive quagga, Dreissena bugensis, and zebra mussels, D. polymorpha, are a serious threat to freshwater ecosystems worldwide. Here, we examine the effectiveness of immersion (≤ 90 min) within 2% or 4% solutions for two commonly used disinfectants (Virasure® Aquatic and Virkon® Aquatic) to cause mortality of adult Dreissena bivalves. Further, we assessed the effectiveness of thermal treatments: steam spray (≥ 100 °C; ≤ 120 s); hot air (− 500 °C; ≤ 60 s); and dry ice exposure (− 78 °C; ≤ 300 g; 15 min). Complete mortality of D. polymorpha was observed following exposure to both disinfectants for 90 min, at both concentrations. However, high but incomplete mortality (40–90%) was recorded for D. bugensis across disinfectant treatments. For both species, complete mortality was achieved following 30 s of steam. In addition, 10 s of hot air and 15 min exposure to 300 g of dry ice can both completely killed groups of D. polymorpha. Overall, although the disinfectants did not cause complete mortality, it appears that relatively brief exposure to thermal treatments could be used to curtail the further spread of Dreissena species.

[Departement_IRSTEA]Eaux [ADD1_IRSTEA]Dynamique et fonctionnement des écosystèmes; International audience; To understand the effects of environmental changes on ecosystems, it is important to determine the factors and mechanisms influencing the strength of species interactions in food webs. However, joint effects of predation risk and additional environmental factors on species interaction strengths in multitrophic systems remain largely unexplored, leaving a substantial gap in our understanding of the links between local environmental characteristics and food web properties. To fill this gap, we investigated the effects of habitat complexity and predation risk by top predatory dragonfly larvae (Aeshna cyanea) on feeding rates and energetic efficiency (i.e. the ratio of acquired and expended energy) of the larvae of three intermediate predatory odonate species (Libellula quadrimaculata, Sympetrum sanguineum, and Ischnura elegans) preying on cladocerans. We hypothesised that predation risk would decrease the feeding rate, especially in the structurally simple habitat, and increase the metabolic rate of all intermediate predators. We also expected higher feeding rates of intermediate predators using aquatic vegetation as a perching site (i.e. Sympetrum and Ischnura) in the structurally complex habitat. Finally, we expected to observe habitat- and predation risk-dependent energetic efficiencies of the intermediate predators driven by changes in feeding and metabolic rates. The effect of predation risk on feeding rates was species specific and differed between the structurally simple and complex habitat. Habitat complexity increased feeding rates but only in the absence of predation risk. Moreover, predation risk signalled by chemical cues significantly increased Sympetrum vulgatum feeding rates but did not influence the feeding rates of the two other intermediate predators. Metabolic rates varied among the three intermediate predators but were not affected by predation risk. Estimated energetic efficiency decreased with intermediate predator body mass and depended, to a lesser extent, on the interactive effect of habitat complexity and predation risk. Our results imply that the effects of habitat complexity and predation risk on trophic interactions are likely to be determined by traits related to foraging and defence of the intermediate predators and their habitat domains, and that energetic efficiency is mainly determined by predator mass. Given that habitat complexity and predation risk can vary substantially across habitats, we conclude that it is important to consider habitat complexity and predation risk to better understand and predict the effects of environmentally driven variations on trophic interaction strength and metabolic rates that underlie the energetic efficiency of individual consumers. This has important implications for population and community dynamics as well as ecosystem functioning.

Environmental concerns and insecticide resistance threaten the sustained efficacy of mosquito control approaches which remain reliant on synthetic chemicals. Plant-based extracts may be an environmentally sustainable and effective alternative to contemporary mosquito control approaches; however, the efficacies of many possible plant-based extracts remain untested. The present study examines the effects of extracts from three floating and three submerged aquatic plants on larval mosquito Culex pipiens mortality, and development to pupal and adult stages. Physical impacts of floating plant species on mosquito mortality and development are also examined. Extracts of Lagarosiphon major and Lemna minuta were toxic, causing significantly increased mosquito mortality compared to plant-free controls. Effects of Azolla filiculoides, Crassula helmsii, Elodea canadensis and Lemna minor were statistically unclear, yet in some cases tended to increase pupal and larval numbers at high extract concentrations. Surface coverage of all floating Lemna species drove significant mosquito mortality through mechanical processes which likely impeded surface respiration by larval mosquitoes. In particular, high-density mats of L. minuta consistently caused total larval mortality. The present study thus suggests that targeted use of specific aquatic plants could assist in mosquito control protocols. However, as the chemical composition of botanic material will differ across spatial and temporal gradients, even for a singular species, localised assessment of the efficacy of plant-based extracts from within areas experiencing problematic mosquito control is required. The application of aquatic plants that are both toxic to larvae and are effective physical control agents presents an economic and effective method of mosquito control.

Duckweeds, such as Lemna minor Linnaeus (Alismatales: Lemnaceae), are common in aquatic habitats and have been suggested to reduce larval mosquito survivorship via mechanical and chemical effects. Furthermore, pond dyes are used increasingly in aquatic habitats to enhance their aesthetics, although they have been shown to attract mosquito oviposition. The present study examined the coupled effects of L. minor and black pond dye on the oviposition selectivity of Culex pipiens Linnaeus (Diptera: Culicidae) mosquitoes in a series of laboratory choice tests. Subsequently, using outdoor mesocosms, the combined influence of duckweed and pond dye on mosquito abundances in aquatic habitats was quantified. Mosquitoes were strongly attracted to duckweed, and oviposited significantly greater numbers of egg rafts in duckweed-treated water compared with untreated controls, even when the duckweed was ground. The presence of pond dye interacted with the duckweed and further enhanced positive selectivity towards duckweed-treated water. The presence of duckweed caused significant and sustained reductions in larval mosquito numbers, whereas the relative effects of dye were not evident. The use of floating aquatic plants such as duckweed, combined with dye, may help reduce mosquito populations via the establishment of population sinks, characterized by high rates of oviposition coupled with high levels of larval mortality.