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Pleistocene glaciations had a tremendous impact on the biota across the Palaearctic, resulting in strong phylogeographic signals of range contraction and rapid postglacial recolonization of the deglaciated areas. Here, we explore the diversity patterns and history of two sibling species of passively dispersing taxa typical of temporary ponds, fairy shrimps (Anostraca). We combine mitochondrial (COI) and nuclear (ITS2 and 18S) markers to conduct a range-wide phylogeographic study including 56 populations of Branchinecta ferox and Branchinecta orientalis in the Palaearctic. Specifically, we investigate whether their largely overlapping ranges in Europe resulted from allopatric differentiation in separate glacial refugia followed by a secondary contact and reconstruct their postglacial recolonization from the inhabited refugia. Our results suggest the existence of distinct refugia for the two species, with genetic divergence among intraspecific lineages consistent with late Pleistocene glacial cycles. While B. ferox lineages originated from Mediterranean refugia, the origin of B. orientalis lineages was possibly located on the Pannonian Plain. We showed that most dispersal events predominantly happened within 100 km, coupled with several recent long-distance events (> 1000 km). Hence the regional habitat density of suitable habitats in Central Europe is possibly a key to the co-existence of the two species. Overall, our study illustrates how isolation in combination with stochastic effects linked to glacial periods are important drivers of the allopatric differentiation of Palaearctic taxa.

Invertebrate species from temporary aquatic ecosystems produce resistant dormant stages (i.e. eggs) that accumulate in long lived mixed egg banks in the sediment. These dormant eggs not only bridge dry phases but also act as propagules for passive dispersal. Large branchiopod crustaceans (e.g. Notostraca, Anostraca and Spinicaudata) produce dormant eggs of variable shapes, sizes and external ornamentation. While these characteristics are often species-specific and have been used in taxonomy, little is known about their ecological significance, for example, their contribution to colonisation success. Here, we explore the idea that variation in egg morphology may impact vector-mediated dispersal and colonisation success of large branchiopods. We studied egg banks from 98 temporary waters across the Northern Cape, South Africa and assessed whether distribution and densities of eggs carried a morphological signal. Overall, our results imply that both size and external structures may impact dispersal to and successful colonisation of temporary waters by large branchiopods. Specifically, our results show that small propagules ( 400 µm), smooth eggs and medium sized (200–300 µm), polygonal eggs were most widely distributed. Ultimately, our approach provides insight in actual colonisation success of species with different egg types and not only on the propensity of the eggs to be picked up and transported by vectors.

The infamous “master manipulators” – intracellular bacteria from the genus Wolbachia – infect a broad range of phylogenetically diverse hosts in terrestrial ecosystems. Wolbachia have important impacts on the ecology and evolution of their hosts with documented effects including induced parthenogenesis, male killing, feminization, and cytoplasmic incompatibility. On the other hand, data on Wolbachia infection in non-terrestrial invertebrates is scarce. Sampling bias and methodological limitations are among the reasons we are unable to detect these bacteria in aquatic organisms. Here we presented a metabarcoding method to detect the co-occurrence of different Wolbachia strains in new, to science, host species: water bears (Tardigrada), freshwater arthropods, and mollusks. In addition, we describe a new Wolbachia strain (supergroup V) and identify a very widespread supergroup A. This supergroup could indicate transinfection and Wolbachia abilities to switch hosts within new environmental conditions, and between hosts that are ecologically connected. Future research should focus on ecological and evolutionary relationships between a new host species and the “master manipulator”.

Dissolved CO2 levels (pCO2) are increasing in lentic freshwaters across the globe. Recent studies have shown that this will impact the nutritional quality of phytoplankton as primary producers, however, the extent to which freshwater zooplankton may also be directly affected remains unclear. We test this in three model species representative of main functional groups of primary consumers in freshwaters; the water flea Daphnia magna, the seed shrimp Heterocypris incongruens and the rotifer Brachionus calyciflorus. We experimentally exposed individuals to three pCO2 levels (1,500; 25,500 and 83,000 ppm) to monitor changes in life history in response to current, elevated and extreme future pCO2 conditions in ponds and shallow lakes. All species had reduced survival under the extreme pCO2 treatment, but the water flea was most sensitive. Body size and reproduction were reduced at 25,500 ppm in the water flea and the seed shrimp and population growth was delayed in the rotifer. Overall, our results show that direct effects of pCO2 could impact the population dynamics of freshwater zooplankton. By differentially modulating the life history of functional groups of primary consumers, elevated pCO2 has the potential to change the evolutionary trajectories of populations as well as the ecological functioning of freshwater communities.

Continued degradation of temporary wet-lands and rapidly declining freshwater biodiversity call for identification of vulnerable species as targets for conservation and management efforts. Branchiopod crustaceans are endemic to temporary waters and rely on banks of drought-resistant eggs in the sediment for survival across dry seasons. These egg banks are like archives to biologists and allow them to estimate population status and resilience, without the need to sample active communities. Such an approach has, however, not yet been fully explored. Here, we investigate egg bank abundance and morpho-species richness to assess the vulnerability of branchiopod communities in dryland landscapes. For study systems, we use 98 temporary wetlands across the Northern Cape Province, South Africa, which contained eggs of Notostraca, Anostraca, Spinicaudata and Cladocera. We invoked the insurance hypothesis to investigate community resilience and studied egg bank abundance to reveal population status. Our results indicate that branchiopod communities become more vulnerable along an aridity gradient, from the semi-arid eastern regions to the arid western parts of the province. Apart from longitude, we also considered a suite of other environmental descriptors to explain variability in egg bank abundance and richness patterns and found that egg bank abundance decreased with alkalinity.

Environmental change jeopardizes the survival of species from variable environments by making the occurrence of favorable conditions less predictable. For organisms with long-lived propagules (e.g., spores, eggs, or seeds), the theory of diversified bet hedging (DBH) predicts that delayed hatching over different growing seasons can help populations avoid extinction. Empirical observations in different organisms are consistent with DBH, but integrated tests that simultaneously validate the main theoretical assumptions and predictions are lacking. In this study, we combine field and multi-generational lab experiments to provide a complete test of DBH. Consistent with DBH predictions, resting egg clutches of the fairy shrimp Branchipodopsis wolfi, which inhabits rain-fed temporary rock pool environments with unpredictable inundations, hatched partially over a succession of inundations with identical hatching cues. Bet hedging was more common in populations from more unpredictable habitats where hatching fractions were lower. This differentiation in hatching strategies was preserved after two generations under common garden conditions, which implies intrinsic (epi-)genetic control of hatching. Finally, a demographic model confirmed that lower hatching fractions increase long-term population growth in unpredictable habitats. With this paper we propose a method to calculate probabilities of successful recruitment for organisms that use imperfect cues and show that this drives selection for variation in life history strategies as part of a DBH strategy.

We used high-throughput sequencing of 16S rRNA to test whether tardigrade species are infected with

River–floodplain connectivity (i.e. lateral hydrological connectivity, LHC) can directly affect the community characteristics by promoting dispersal of organisms but can also have profound indirect effects by altering local habitat characteristics. A major challenge is to disentangle the relative importance of direct and indirect effects of LHC on organisms. Combining taxonomic data with trait information allows a more mechanistic understanding of how LHC affect biotic communities in floodplains. Here, we attempted to determine the relative importance of the direct and indirect effects of LHC on local environmental variables and community characteristics (taxonomic and trait composition) of three different taxonomic organism groups in a set of 33 temporary floodplain pans along a gradient of LHC. In addition, we specifically aimed to unravel the underlying mechanisms shaping patterns of taxonomic diversity by partitioning compositional dissimilarity between ponds into components of nestedness and spatial turnover. Variation partitioning revealed that most differences in macroinvertebrate and zooplankton community composition between pans resulted from variation in local environmental variables, particularly macrophyte cover and the presence of fish. For large branchiopod crustaceans, however, partitioning indicated that LHC did significantly affect both taxonomic and trait community composition, and reduced local taxon diversity. Partitioning taxonomic and trait β‐diversity showed that community dissimilarity between pans was largely determined by turnover, rather than by nestedness. Overall, our study revealed that the effects of LHC on aquatic invertebrate communities act mainly indirectly by altering local environmental conditions. Although the effects of LHC were significant, they were small compared to those of environmental variables. Our results from the partitioning of taxonomic and trait β‐diversity have important implications for biodiversity conservation efforts in the Ndumo region. We demonstrate the need to conserve multiple pans along the LHC gradient to sustain high regional diversity. A common practice in the study area mainly focuses on the conservation of river‐connected or larger pans

International audience; Intense anthropogenic disturbance threatens temporary pond ecosystems and their associated fauna across the Palearctic. Since fairy shrimps (Crustacea, Branchiopoda) are endemic to temporary ponds, populations are declining due to habitat loss and it is important to define adequate units for conservation. Phylogeographic reconstructions, based on genetic variation, provide valuable information for defining evolutionary and conservation units, especially for organisms with high levels of cryptic diversity like many fairy shrimps. We studied a total of 152 individuals of the fairy shrimp Branchipus schaefferi from 79 populations across the Palearctic and used mitochondrial (CO1) and nuclear (ITS1) DNA data to reconstruct the phylogeography of the species. Our results show that B. schaefferi comprises four highly diverged (10.3–16.5%) evolutionary clades. The present‐day haplotypes within each of the clades probably diverged from lineages that were maintained in separate refugia during the Pleistocene ice ages. While two clades represent distinct geographic regions, the two remaining clades have more wide and overlapping ranges. In addition, the limited number of shared haplotypes among populations from geographically distant regions within three of the clades suggest recent long‐distance dispersal events. Overall, the studied B. schaefferi dataset comprises high levels of genetic differentiation, without a clear morphological signal. Phylogenetic searches and pairwise genetic distances suggest that the studied lineages belong to a complex of four morphologically cryptic species. Since these four evolutionary old clades persist (±2 million years), despite overlapping geographic ranges and since they span a variety of ecological conditions, they should be considered as separate evolutionary significant units for conservation.

Although aquatic organisms are increasingly exposed to pollutants and abnormally high temperatures as a consequence of climate change, interactive effects between those stressors remain poorly assessed. Especially in ectotherms, such as fish, increases in ambient temperature are expected to affect fitness-related traits and physiology. We used the turquoise killifish Nothobranchius furzeri to study the effects of a range of 3,4-dichloroaniline concentrations (0, 50, 100 mu g/L) in combination with two temperature conditions (control and control +4 degrees C) during four months of exposure. As part of an integrated multi-level approach, we quantified effects on classic life history traits (size, maturation time, body mass, fecundity), critical thermal maximum and physiology (energy reserves and stress-associated enzymatic activity). While no interactive effects of 3,4-DCA exposure and increased temperature emerged, our results do show a negative effect of 3,4-DCA on thermal tolerance. This finding is of particular relevance in light of increasing temperatures under climate change. Due to increases in pest species and faster degradation of 3,4-DCA under higher temperatures, increased use of the pesticide is expected under climate change which, in turn, could result in a decreased tolerance of aquatic organisms to high temperatures.

Simple Summary In recent decades, the riverine ecosystems have been considered to evaluate the aquatic biological diversity, hydrological variations, and ecosystem services. However, climatic change scenarios and anthropogenic interventions are expected to shift from perennial to intermittent rivers with possible repercussion on aquatic biodiversity and human well-being. Our study identified a significant reduction in the Mediterranean intermittent river streamflow with an increase of zero flow days in the last decades. Furthermore, the aquatic invertebrates showed variations during the transition from drying to rewetting with a significantly changing species adapted to the flowing conditions (rheophilic taxa) to non-flowing water. The importance of the disconnected pools as refuges during the dry condition was recognised to protect some endemic species and contribute to the recolonisation after the rewetting events. Include these important aquatic ecosystems in management and conservancy policies is a challenge that will contribute to preserving the freshwater resources and the biological diversity for our future generations. Abstract Intermittent rivers and ephemeral streams (IRES) are increasingly studied because of their often-unique aquatic and terrestrial biodiversity, biogeochemical processes and associated ecosystem services. This study is the first to examine the hydrological, physicochemical and taxonomic variability during the dry-wet transition of an intermittent river in the Chilean Mediterranean Zone. Based on 30-years of river monitoring data and the TREHS tool, the hydrology of the river was characterised. Overall, the river shows a significant reduction in streamflow (−0.031 m3/s per year) and a substantial increase of zero flow days (+3.5 days per year). During the transition of hydrological states, variations were observed in the environmental conditions and invertebrate communities. During the drying phase, abundance, richness, and diversity were highest, while species turn-over was highest during base flow conditions. The disconnected pools and the flow resumption phases were characterised by high proportions of lentic taxa and non-insects, such as the endemic species of bivalves, gastropods, and crustaceans, highlighting the relevance of disconnected pools as refuges. Future climatic change scenarios are expected to impact further the hydrology of IRES, which could result in the loss of biodiversity. Biomonitoring and conservation programmes should acknowledge these important ecosystems.

As many freshwaters are chemically polluted, one of the challenges for policy makers is to determine the potential impact of these pollutants on ecosystems and to define safe concentrations. Common practice is the use of ecotoxicological assays to assess the response of model organisms from different trophic levels such as algae, invertebrates and fish during exposure to dilutions of a specific compound. Ideally, ecotoxicological assessments of (pseudo-)persistent chemicals should be performed across the life-cycle or even multiple generations for an accurate risk assessment. Multigenerational tests with fish are, however, impractical and costly given the long lifespan and generation time of classic model species. Here, we suggest a framework for more relevant, time- and cost-efficient fish-based testing in ecotoxicology and align it with accredited test guidelines. Next, we introduce an upcoming fish model, the turquoise killifish Nothobranchius furzeri, and show how it facilitates such research agendas due to a short lifespan and generation time. Through a review of fish-based exposure studies with a set of reference toxicants, we position N. furzeri as a sensitive species, suitable for screening effects of different pollutant types. Ultimately, we perform a cost-benefit analysis and propose a plan of action for the introduction of N. furzeri into accredited test guidelines.

Low doses of neuroactive chemicals end up in the environment and disrupt behaviour of non-target organisms. Although a whole range of studies have documented pollutant-induced changes in behaviour, natural daily variability in behaviour is rarely taken into account. This is surprising because biological rhythms may affect the outcome of experiments, are adaptive and are expected to be sensitive to neurochemical exposure. Here, we exploit daily behavioural variation in the fish model Nothobranchius furzeri to examine if behavioural effects of chronic exposure (74 days) to an environmentally relevant level (28 ng/L) of the neurochemical fluoxetine depend on the time of day. Fluoxetine exposure induced an increase in anxiety-related behaviour that was slightly more pronounced in the evening compared to the morning. Moreover, open-field locomotor activity was disrupted and daily patterns in activity lifted upon exposure to the compound. These results imply that short-term behavioural variability should be considered both to standardise ecological risk assessment of neuroactive chemicals as well as to better understand the environmental impact of such compounds in aquatic ecosystems. ispartof: Environmental Pollution vol:276 ispartof: location:England status: Published online

Pesticides are crucial to improve agricultural productivity, but often adversely affect surrounding aquatic systems and their fauna. To determine the environmental risk of pesticides, routine ecotoxicological tests are performed on several organisms, including standard fish models. However, these typically do not include fish species from variable habitats and with non-generic life-histories. In particular, inhabitants from temporary ponds such as annual killifish are conventionally understood to be resilient to natural stressors which could translate to higher pesticide resistance or, alternatively, trade-off with their resistance to pesticides and render them more sensitive than classic fish models. Using standard exposure tests, we assessed short-term toxicity effects of two commonly used pesticides, Roundup and cypermethrin, on the annual killifish Nothobranchius neumanni, and compared its sensitivity with that of classic fish models. For Roundup, we found a 72 h-LC50 of 1.79 ± 0.11 mg/L, which is lower than the values reported for zebrafish, medaka, fathead minnow and rainbow trout, suggesting that N. neumanni is more sensitive to the compound. The opposite was true for cypermethrin, with a 72 h-LC50 of 0.27 ± 0.03 mg/L. However, these LC50-values do not deviate strongly from those reported for other fish species, supporting earlier findings in the congeneric N. furzeri that the sensitivity of annual killifish to pollutants is similar to that of classic fish models despite their assumed robustness to environmental stress.

Ecological risks of a pollutant are typically assessed via short-term exposure of model organisms to that single compound. Such tests are informative, but cannot ascertain effects of long-term and multigenerational mixed-stressor exposure with which organisms are often confronted in their natural environment. Therefore, full life-cycle and multigenerational tests are needed. Yet, these are hampered due to long lifespans and generation times of many standard laboratory species, in particular for vertebrates such as fish. With a typical lifespan of 6 months and a generation time of about 3 months, the turquoise killifish (Nothobranchius furzeri) may be an ideal model for multigenerational testing. In this study, we assessed the impact of full life-cycle exposure to the emerging pollutant fluoxetine (0, 0.5 μg/L) in combination with chronic exposure during adulthood to the pesticide 3,4-dichloroaniline (0, 50, 100 μg/L) over two successive generations of N. furzeri. Overall, both life-history and behaviour were affected by exposure to fluoxetine and 3,4-DCA. Inhibitory effects of single chemical exposure on growth and fecundity were generation-dependent, while enhanced swimming acceleration and feeding in response to fluoxetine were dependent on the presence of 3,4-DCA. Together, these findings show the relevance of a multi-stressor approach across successive generations. Although full life-cycle and multigenerational tests are typically assumed to be impractical and costly for fish, we deliver an effective demonstration that such studies are possible within a timespan of less than 6 months with the killifish N. furzeri as a model organism.

Social and mating behavior are fundamental fitness determinants in fish. Although fish are increasingly exposed to pharmaceutical compounds that may alter expression of such behavior, potential effects are understudied. Here, we examine the impact of lifelong exposure to two concentrations (0.7 and 5.3 μg/L) of the antidepressant fluoxetine on fecundity and social behavior (i.e. sociability and male-male aggression) in the turquoise killifish, Nothobranchius furzeri. When exposed to the highest concentration of fluoxetine (5.3 μg/L), fish were smaller at maturation but they more frequently engaged in mating. In addition, in both fluoxetine treatments females roughly doubled their overall fecundity while egg fertilization rates were the same for exposed and unexposed fish. Although aggression of male fish was not impacted by fluoxetine exposure, exposed male fish (5.3 μg/L) spent more time in the proximity of a group of conspecifics, which implies an increased sociability in these individuals. Overall, the results of this study indicate that exposure to fluoxetine may result in disrupted male sociability, increased mating frequency and an increased reproductive output in fish populations.

Most temporary pond zooplankton species produce drought-resistant eggs that accumulate in the sediment and form an egg bank. When a pond dries and the egg bank is exposed, wind erodes eggs and wind action has been suggested as an important determinant of population demographics. While field observations suggest that egg bank erosion may be highest shortly after pond drying and physical disturbance of the sediment crust, this remains to be tested empirically. We performed a laboratory wind tunnel experiment to assess the effects of wind speed and sediment characteristics on egg pickup rates over time in a controlled environment. We used sediment samples in which an egg bank of the fairy shrimp Branchipodopsis wolfi was embedded and compared the number of eggs that blew away from dry, drying and disturbed egg banks as a function of time. Few eggs were picked up when the egg bank was dry prior to exposure, even at winds of 70 km h −1. Most eggs were eroded when the egg bank was exposed to wind before it dried out, after the last water evaporated. Likewise, physical disturbance resulted in strong erosion fluxes. Overall, our results suggest that the state of the egg bank may be more important for egg bank erosion rates than the prevailing wind speed or the wind exposure time. Also, our findings are worrying in the context of climate change since they imply that predicted increases in drying events and reduced inundation lengths may compromise egg bank persistence in temporary ponds.

Fish models are essential for research in many biological and medical disciplines. With a typical lifespan of only 6 months, the Turquoise killifish (Nothobranchius furzeri) was recently established as a time- and cost-efficient model to facilitate whole-life and multigenerational studies in several research fields, including behavioural ecotoxicology. Essential information on the behavioural norm and on how laboratory conditions affect behaviour, however, is deficient. In the current study, we examined the impact of the social and structural environment on a broad spectrum of behavioural endpoints in N. furzeri. While structural enrichment affected only fish boldness and exploratory behaviour, fish rearing density affected the total body length, locomotor activity, boldness, aggressiveness and feeding behaviour of N. furzeri individuals. Overall, these results contribute to compiling a behavioural baseline for N. furzeri that increases the applicability of this new model species. Furthermore, our findings will fuel the development of improved husbandry protocols to maximize the welfare of N. furzeri in a laboratory setting.

Although temporary wetlands are often biodiversity hotspots that deliver multiple ecosystem services, they are also threatened by human exploitation. We conducted a comparative field study to investigate the impact of reserve protection on the diversity and community structure of aquatic macroinvertebrates of temporary wetlands (pans) in South Africa. Specifically, we compared the diversity and community composition of macroinvertebrates with a special focus on large branchiopod crustaceans in pans of a protected nature reserve (Ndumo Game Reserve) with that of pans in the surrounding anthropogenically disturbed area (Ndumo Communal Area). Our results show that reserve protection has a significant positive effect on the diversity and community structure of the aquatic macroinvertebrates. The taxon diversity for macroinvertebrates in general and large branchiopods in particular was significantly higher in the Ndumo Game Reserve, compared with the Ndumo Communal Area. Overall, our results illustrate the need for continued protection of reserve areas and pans in this tropical region in South Africa for the conservation of macroinvertebrate species

Ongoing pollution of aquatic ecosystems with neurochemical compounds warrants an improved understanding of how this affects key organisms. Neurochemicals are shown to alter the behaviour of common study species but it remains difficult to translate these results to biologically meaningful predictions across taxa. This is partly because studies on species with non-generic life-history strategies such as many freshwater crustaceans are currently underrepresented. Here, we use a laboratory experiment to assess baseline behavioural variation (spontaneous activity level and geotaxic behaviour) in the freshwater fairy shrimp Branchipodopsis wolfi and how this is affected by chronic exposure to an environmentally-relevant concentration of the anxiolytic pharmaceutical fluoxetine. The more conspicuously coloured and larger females of the species were overall less active and more benthic than males. Moreover, amongst females, vertical activity was negatively associated with size, while an opposite relationship was found for males. These trade-offs are likely part of an antipredator strategy to reduce the probability of being detected by visual hunters, but disappeared after exposure to fluoxetine. This is of particular interest since it is an effective proof of principle that neurochemicals may impact ecologically-relevant trade-offs between conspicuous morphology and antipredator behaviour. In natural ecosystems, such disturbed antipredator behavioural responses could have far-reaching fitness consequences. ispartof: Aquatic Toxicology vol:237 ispartof: location:Netherlands status: published

To assess whether the annual killifish Nothobranchius wattersi responds plastically to a desiccation risk and whether this response is life stage dependent, life-history traits such as maturation time, fecundity and life span were experimentally measured in N. wattersi that were subjected to a drop in water level either as juveniles, as adults or both as juveniles and adults. Fish that were exposed to simulated pool drying as juveniles did not show changes in reproductive output or life span. Adults reacted by doubling short term egg deposition at the cost of a shorter lifespan. Overall, these results suggest that annual fish species can use phenotypic plasticity to maximize their reproductive output when faced with early pond drying, but this response appears to be life-stage specific. In addition to frogs and aquatic insects, phenotypic plasticity induced by forthcoming drought is now also confirmed in annual fishes and could well be a common feature of the limited number of fish taxa that manage to survive in this extreme environment.

At some stage in their life cycle, most zooplankton in temporary waters produce dormant eggs that assemble in a persistent egg bank to cope with unfavourable conditions. As part of a risk-spreading strategy, only a fraction of the egg bank hatches during a single inundation. Besides this dispersal in time, resistant dormant eggs also disperse in space via vectors including wind, water and animals. The structure and functioning of the dormant egg bank has important consequences for (meta) population and (meta) community structure and dynamics. Here, we merge empirical and theoretical data into a conceptual framework for the study of population and community responses in temporary ponds along a gradient in hydrological disturbance. Overall, we conclude that changes in hydrological disturbance may compromise both the abiotic (i.e. water quality) and biotic (i.e. population and community processes) integrity of temporary pools which is especially relevant in light of ongoing anthropogenic alterations in the hydrology of inland waters.

Variation in life-history strategies along a slow-fast continuum is largely governed by life-history trade-offs. The pace-of-life syndrome hypothesis (POLS) expands on this idea and suggests coevolution of these traits with personality and physiology at different levels of biological organization. However, it remains unclear to what extent covariation at different levels aligns and if also behavioral patterns such as diurnal activity changes should be incorporated. Here, we investigate variation in life-history traits as well as behavioral variation at the individual, sex and population level in the Turquoise killifish Nothobranchius furzeri. We performed a common garden laboratory experiment with four populations that differ in pond permanence and scored life-history and behavioral (co-) variation at the individual and population level for both males and females. In addition, we focused on diurnal activity change as a behavioral trait that remains understudied in ecology. Our results demonstrate sex-specific variation in adult body size and diurnal activity change among populations that originate from ponds with differences in permanence. However, there was no pond permanence-dependent divergence in maturation time, juvenile growth rate, fecundity and average activity level. With regard to behavior, individuals differed consistently in locomotor activity and diurnal activity change while, in contrast with POLS predictions, we found no indications for life-history and behavioral covariation at any level. Overall, this study illustrates that diurnal activity change differs consistently between individuals, sexes and populations although this variation does not appear to match POLS predictions. ispartof: Peerj vol:7 ispartof: location:United States status: published

Pharmaceuticals are essential for human well-being, but their increasing and continuous use pollutes the environment. Although behavioral ecotoxicology is increasingly advocated to assess the effects of pharmaceutical pollution on wildlife and ecosystems, a consensus on the actual environmental risks is lacking for most compounds. The main limitation is the lack of standardized reproducible tests that are based on sensitive behavioral endpoints and that accommodate a high ecological relevance. In the present study, we assessed the impact of a 3-wk exposure to the antidepressant fluoxetine on multiple behavioral traits in the promising new model organism Nothobranchius furzeri (turquoise killifish). Overall, our study shows that fluoxetine can impact feeding behavior, habitat choice in a novel environment, and antipredator response of N. furzeri individuals; effects on spontaneous activity and exploration tendency were less pronounced. However, effects became only apparent when individuals were exposed to fluoxetine concentrations that were 10 times higher than typical concentrations in natural aquatic environments. Ecotoxicologists are challenged to maximize both the reliability and ecological validity of risk assessments of pollutants. Our study contributes to the development of a time- and cost-efficient, standardized ecotoxicological test based on sensitive, ecologically relevant behavioral endpoints in N. furzeri. Environ Toxicol Chem 2019;38:262-270. © 2018 SETAC. ispartof: ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY vol:38 issue:1 pages:262-270 ispartof: location:United States status: published

It is typically assumed that for species to persist in working landscapes, they must either persist alongside agricultural pressures (i.e. land-sharing) or become restricted to remnant patches of natural habitat (i.e land-sparing). However, a third possibility is that species survive in stable ecological refuges that then supply the surrounding matrix with immigrants. In this study, we examined the potential for refuge-colonisation dynamics across two Key Biodiversity Areas dominated by commercial farmland in South Africa. We combined six years of remote sensing and two years of field surveys to examine mountains and rocky outcrops as ecological refuges using butterflies as indicators of environmental change. Vegetation on mountains and outcrops had higher and less variable productivity and moisture retention than the matrix, even across exceptionally wet and dry years. Moreover, butterflies in the matrix were a nested subset of species from the mountains and outcrops, and there was little evidence that species with certain traits were limited to either habitat. This suggests that species can retreat to ecological refuges during harsh conditions and recolonise the surrounding matrix once conditions improve. Ecological refuges can, therefore, unify land-sharing and land-sparing because their targeted protection would support the persistence of species throughout wider landscapes.

Bacterial endosymbionts of aquatic invertebrates remain poorly studied. This is at least partly due to a lack of suitable techniques and primers for their identification. We designed a pair of non-degenerate primers which enabled us to amplify a fragment of ca. 500 bp of the 16S rRNA gene from various known bacterial endosymbiont species. By using this approach, we identified four bacterial endosymbionts, two endoparasites and one uncultured bacterium in seven, taxonomically diverse, freshwater crustacean hosts from temporary waters across a wide geographical area. The overall efficiency of our new WOLBSL and WOLBSR primers for amplification of the bacterial 16S rRNA gene was 100%. However, if different bacterial species from one sample were amplified simultaneously, sequences were illegible, despite a good quality of PCR products. Therefore, we suggest using our primers at the first stage of bacterial endosymbiont identification. Subsequently, genus specific primers are recommended. Overall, in the era of next-generation sequencing our method can be used as a first simple and low-cost approach to identify potential microbial symbionts associated with freshwater crustaceans using simple Sanger sequencing. The potential to detected bacterial symbionts in various invertebrate hosts in such a way will facilitate studies on host-symbiont interactions and coevolution. ispartof: PEERJ vol:6 issue:12 ispartof: location:United States status: published

The killifish Nothobranchius furzeri is an emerging model organism in the field of ecotoxicology and its applicability in acute and chronic ecotoxicity testing has been demonstrated. Overall, the sensitivity of the species to toxic compounds is in the range with, or higher than, that of other model species. This work describes protocols for acute, chronic, and multigenerational bioassays of single and combined stressor effects on N. furzeri. Due to its short maturation time and life-cycle, this vertebrate model allows the study of endpoints such as maturation time and fecundity within four months. Transgenerational full life-cycle exposure trials can be performed in as little as 8 months. Since this species produces eggs that are drought-resistant and remain viable for years, the on-site culture of the species is not needed but individuals can be recruited when required. The protocols are designed to measure life-history traits (mortality, growth, fecundity, weight) and critical thermal maximum.

The killifish Nothobranchius furzeri is an emerging model organism in the field of ecotoxicology and its applicability in acute and chronic ecotoxicity testing has been demonstrated. Overall, the sensitivity of the species to toxic compounds is in the range with, or higher than, that of other model species. This work describes protocols for acute, chronic, and multigenerational bioassays of single and combined stressor effects on N. furzeri. Due to its short maturation time and life-cycle, this vertebrate model allows the study of endpoints such as maturation time and fecundity within four months. Transgenerational full life-cycle exposure trials can be performed in as little as 8 months. Since this species produces eggs that are drought-resistant and remain viable for years, the on-site culture of the species is not needed but individuals can be recruited when required. The protocols are designed to measure life-history traits (mortality, growth, fecundity, weight) and critical thermal maximum.

Background Higher temperatures and increased environmental variability under climate change could jeopardize the persistence of species. Organisms that rely on short windows of rainfall to complete their life-cycles, like desert annual plants or temporary pool animals, may be particularly at risk. Although some could tolerate environmental changes by building-up banks of propagules (seeds or eggs) that buffer against catastrophes, climate change will threaten this resilience mechanism if higher temperatures reduce propagule survival. Using a crustacean model species from temporary waters, we quantified experimentally the survival and dormancy of propagules under anticipated climate change and used these demographic parameters to simulate long term population dynamics. Results By exposing propagules to present-day and projected daily temperature cycles in an 8 month laboratory experiment, we showed how increased temperatures reduce survival rates in the propagule bank. Integrating these reduced survival rates into population models demonstrated the inability of the bank to maintain populations; thereby exacerbating extinction risk caused by shortened growing seasons. Conclusions Overall, our study demonstrates that climate change could threaten the persistence of populations by both reducing habitat suitability and eroding life-history strategies that support demographic resilience. Electronic supplementary material The online version of this article (10.1186/s12898-018-0158-z) contains supplementary material, which is available to authorized users.