668 results on '"Hart, AG"'
Search Results
2. Hunting trophy import bans proposed by the UK may be ineffective and inequitable as conservation policies in multiple social‐ecological contexts
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Clark, DA, Brehony, P, Dickman, A, Foote, L, Hart, AG, Jonga, C, Mbiza, MM, Roe, D, Sandbrook, C, Brehony, P [0000-0003-1315-7683], Roe, D [0000-0002-6547-6427], Sandbrook, C [0000-0002-9938-4934], and Apollo - University of Cambridge Repository
- Subjects
CITES ,Ecology ,CBNRM ,legislation ,sustainable use ,bans ,trophy hunting ,Ecology, Evolution, Behavior and Systematics ,Nature and Landscape Conservation - Abstract
The UK government is considering legislation to prohibit the importation of hunting trophies. We examine documented social, ecological, and political outcomes of two previous such bans. We find that the UK government's proposal shares the shortcomings of existing bans that have (1) failed to address, or have even amplified, key threats to hunted species, (2) imposed costs on citizens of other countries, and (3) delegitimized the Convention on International Trade in Endangered Species (CITES). Trophy import bans are blunt policy instruments that can cause more problems than they solve.
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- 2023
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3. Using citizen science data to assess the population genetic structure of the common yellowjacket wasp, Vespula vulgaris.
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Cunningham-Eurich I, Kontou D, Yordanova M, Maeda-Obregon A, Favreau E, Wang J, Hart AG, and Sumner S
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- Animals, Insecta, Introduced Species, Genetics, Population, Wasps genetics, Citizen Science
- Abstract
Monitoring insect genetic diversity and population structure has never been more important to manage the biodiversity crisis. Citizen science has become an increasingly popular tool to gather ecological data affordably across a wide range of spatial and temporal scales. To date, most insect-related citizen science initiatives have focused on occurrence and abundance data. Here, we show that poorly preserved insect samples collected by citizen scientists can yield population genetic information, providing new insights into population connectivity, genetic diversity and dispersal behaviour of little-studied insects. We analysed social wasps collected by participants of the Big Wasp Survey, a citizen science project that aims to map the diversity and distributions of vespine wasps in the UK. Although Vespula vulgaris is a notorious invasive species around the world, it remains poorly studied in its native range. We used these data to assess the population genetic structure of the common yellowjacket V. vulgaris at different spatial scales. We found a single, panmictic population across the UK with little evidence of population genetic structuring; the only possible limit to gene flow is the Irish sea, resulting in significant differentiation between the Northern Ireland and mainland UK populations. Our results suggest that queens disperse considerable distances from their natal nests to found new nests, resulting in high rates of gene flow and thus little differentiation across the landscape. Citizen science data has made it feasible to perform this study, and we hope that it will encourage future projects to adopt similar practices in insect population monitoring., (© 2023 The Authors. Insect Molecular Biology published by John Wiley & Sons Ltd on behalf of Royal Entomological Society.)
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- 2023
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4. Ten years of coverage of trophy hunting in UK newspapers
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Yeomans, N, Hare, D, Dröge, E, and Hart, AG
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General Medicine - Abstract
Hunting is an increasingly contentious topic. Trophy hunting, whereby people hunt individual animals with desirable characteristics in order to keep body parts (e.g. horns, heads, hides, antlers) as mementos, is especially contested. Political pressure, often in the form of trophy import bans, is being applied in multiple nations, and campaigns to ban trophy hunting, or trophy imports, attract considerable media attention. However, trophy hunting often has conservation value, acting to protect habitat and provide income for local communities. Assuming that media coverage can influence public and political opinion, negative or simplistic media coverage of trophy hunting has the potential to cause adverse outcomes for conservation and local communities. Here, we analyse coverage of trophy hunting from July 2010 - June 2020 (five years before and five years after the death of Cecil the Lion) in the most popular UK media outlets (624 articles in total), assessing the overall sentiment of each article, and the species and countries covered. Ninety percent of all coverage occurred after the death of Cecil the lion, marking this event as a watershed moment in UK mainstream media depiction of trophy hunting. The overall sentiment of articles was largely against trophy hunting (63.1%), and this was more pronounced in tabloids (84.2%) than broadsheets (42.2%). Pro-trophy hunting articles were very uncommon overall (3.5%). Articles that described the complexity of trophy hunting decreased following Cecil and were most common in pre-Cecil broadsheets (35.7%, dropping to 30.6%) and rarest in post-Cecil tabloids (3.1%). Articles focussed mainly on charismatic but rarely hunted species including lion, elephant and rhino, with commonly hunted species (such as impala or Cape buffalo) only rarely being mentioned. When countries were mentioned, southern African nations predominated, with four nations (Zimbabwe, South Africa, Namibia and Botswana) being named in 68% of qualifying articles. We conclude that simplistic media depiction of trophy hunting has the potential to cause negative outcomes for conservation through its impact on public perception and political opinion.
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- 2022
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5. Threats posed to conservation by media misinformation.
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Hart AG, Cooney R, Dickman A, Hare D, Jonga C, Johnson PK, Louis MP, Lubilo R, Roe D, Semcer C, and Somerville K
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- Communication, Conservation of Natural Resources, Social Media
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- 2020
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6. Subscriber toll dialling in New Zealand
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Honore, KG, Skurr, JA, and Hart, AG
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- 1977
7. N.Z.I.E. transaction summary: Subscriber toll dialling in New Zealand
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Honore, KG, Skurr, JA, and Hart, AG
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- 1977
8. Terrestrial emigration behaviour of two invasive crayfish species.
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Thomas JR, Masefield S, Hunt R, Wood MJ, Hart AG, Hallam J, Griffiths SW, and Cable J
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- Animals, Aquaculture, Astacoidea, Fresh Water, Animal Migration physiology, Ecosystem, Introduced Species
- Abstract
To disperse between isolated waterbodies, freshwater organisms must often cross terrestrial barriers and many freshwater animals that are incapable of flight must rely on transport via flooding events, other animals or anthropogenic activity. Decapods such as crayfish, on the other hand, can disperse to nearby waterbodies by walking on land, a behaviour that has facilitated the spread of invasive species. Overland movement could play a key role in the management of non-native crayfish, though to what extent terrestrial emigration occurs in different species is poorly understood. Here, we directly compared the terrestrial emigration tendency of two non-native crayfish species in Great Britain; red swamp (Procambarus clarkii) and signal (Pacifastacus leniusculus) crayfish. We found that both species emigrated from the water and that there was no significant difference in terms of their terrestrial emigration tendency, suggesting that there is a risk both of these species will migrate overland and disperse to new habitats. This study shows that terrestrial emigration is an important behavioural trait to consider when preventing the escape of crayfish from aquaculture and further spread of invasive species., (Copyright © 2019 Elsevier B.V. All rights reserved.)
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- 2019
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9. Phenotypic Plasticity of Nest-Mate Recognition Cues in Formica exsecta Ants.
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Martin SJ, Drijfhout FP, and Hart AG
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- Animals, Ants, Cues, Nesting Behavior, Species Specificity, Adaptation, Physiological physiology, Odorants, Reproduction physiology
- Abstract
It is well established that many ant species have evolved qualitatively distinct species-specific chemical profile that are stable over large geographical distances. Within these species profiles quantitative variations in the chemical profile allows distinct colony-specific odours to arise (chemotypes) that are shared by all colony members. This help maintains social cohesion, including defence of their colonies against all intruders, including con-specifics. How these colony -level chemotypes are maintained among nest-mates has long been debated. The two main theories are; each ant is able to biochemically adjust its chemical profile to 'match' that of its nest-mates and or the queen, or all nest-mates share their individually generated chemical profile via trophollaxis resulting in an average nest-mate profile. This 'mixing' idea is better known as the Gestalt model. Unfortunately, it has been very difficult to experimentally test these two ideas in a single experimental design. However, it is now possible using the ant Formica exsecta because the compounds used in nest-mate recognition compounds are known. We demonstrate that workers adjust their profile to 'match' the dominant chemical profile within that colony, hence maintaining the colony-specific chemotype and indicates that a 'gestalt' mechanism, i.e. profile mixing, plays no or only a minor role.
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- 2019
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10. A hidden Markov model for describing turbostratic disorder applied to carbon blacks and graphene.
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Hart AG, Hansen TC, and Kuhs WF
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A mathematical framework is presented to represent turbostratic disorder in materials like carbon blacks, smectites and twisted n-layer graphene. In particular, the set of all possible disordered layers, including rotated, shifted and curved layers, forms a stochastic sequence governed by a hidden Markov model. The probability distribution over the set of layer types is treated as an element of a Hilbert space and, using the tools of Fourier analysis and functional analysis, expressions are developed for the scattering cross sections of a broad class of disordered materials.
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- 2019
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11. A Markov theoretic description of stacking-disordered aperiodic crystals including ice and opaline silica.
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Hart AG, Hansen TC, and Kuhs WF
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This article reviews the Markov theoretic description of one-dimensional aperiodic crystals, describing the stacking-faulted crystal polytype as a special case of an aperiodic crystal. Under this description the centrosymmetric unit cell underlying a topologically centrosymmetric crystal is generalized to a reversible Markov chain underlying a reversible aperiodic crystal. It is shown that for the close-packed structure almost all stackings are irreversible when the interaction reichweite s > 4. Moreover, the article presents an analytic expression of the scattering cross section of a large class of stacking-disordered aperiodic crystals, lacking translational symmetry of their layers, including ice and opaline silica (opal CT). The observed stackings and their underlying reichweite are then related to the physics of various nucleation and growth processes of disordered ice. The article discusses how the derived expressions of scattering cross sections could significantly improve implementations of Rietveld's refinement scheme and compares this Q-space approach with the pair-distribution function analysis of stacking-disordered materials.
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- 2018
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12. Birds of a feather flock together: Insights into starling murmuration behaviour revealed using citizen science.
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Goodenough AE, Little N, Carpenter WS, and Hart AG
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- Animals, Ecosystem, Predatory Behavior, Seasons, Behavior, Animal physiology, Starlings physiology
- Abstract
Pre-roost murmuration displays by European starlings Sturnus vulgaris are a spectacular example of collective animal behaviour. To date, empirical research has focussed largely on flock movement and biomechanics whereas research on possible causal mechanisms that affect flock size and murmuration duration has been limited and restricted to a small number of sites. Possible explanations for this behaviour include reducing predation through the dilution, detection or predator confusion effects (the "safer together" hypotheses) or recruiting more birds to create larger (warmer) roosts (the "warmer together" hypothesis). We collected data on size, duration, habitat, temperature and predators from >3,000 murmurations using citizen science. Sightings were submitted from 23 countries but UK records predominated. Murmurations occurred across a range of habitats but there was no association between habitat and size/duration. Size increased significantly from October to early February, followed by a decrease until the end of the season in March (overall mean 30,082 birds; maximum 750,000 birds). Mean duration was 26 minutes (± 44 seconds SEM). Displays were longest at the start/end of the season, probably due to a significant positive relationship with day length. Birds of prey were recorded at 29.6% of murmurations. The presence of predators including harrier Circus, peregrine Falco peregrinus, and sparrowhawk Accipiter nisus was positively correlated with murmuration size (R2 = 0.401) and duration (R2 = 0.258), especially when these species were flying near to, or actively engaging with, starlings. Temperature was negatively correlated with duration but the effect was much weaker than that of day length. When predators were present, murmurations were statistically more likely to end with all birds going down en masse to roost rather than dispersing from the site. Our findings suggest that starling murmurations are primarily an anti-predator adaptation rather than being undertaken to attract larger numbers of individuals to increase roost warmth.
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- 2017
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13. Recognition of endophytic Trichoderma species by leaf-cutting ants and their potential in a Trojan-horse management strategy.
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Rocha SL, Evans HC, Jorge VL, Cardoso LAO, Pereira FST, Rocha FB, Barreto RW, Hart AG, and Elliot SL
- Abstract
Interactions between leaf-cutting ants, their fungal symbiont ( Leucoagaricus ) and the endophytic fungi within the vegetation they carry into their colonies are still poorly understood. If endophytes antagonistic to Leucoagaricus were found in plant material being carried by these ants, then this might indicate a potential mechanism for plants to defend themselves from leaf-cutter attack. In addition, it could offer possibilities for the management of these important Neotropical pests. Here, we show that, for Atta sexdens rubropilosa , there was a significantly greater incidence of Trichoderma species in the vegetation removed from the nests-and deposited around the entrances-than in that being transported into the nests. In a no-choice test, Trichoderma- infested rice was taken into the nest, with deleterious effects on both the fungal gardens and ant survival. The endophytic ability of selected strains of Trichoderma was also confirmed, following their inoculation and subsequent reisolation from seedlings of eucalyptus. These results indicate that endophytic fungi which pose a threat to ant fungal gardens through their antagonistic traits, such as Trichoderma , have the potential to act as bodyguards of their plant hosts and thus might be employed in a Trojan-horse strategy to mitigate the negative impact of leaf-cutting ants in both agriculture and silviculture in the Neotropics. We posit that the ants would detect and evict such 'malign' endophytes-artificially inoculated into vulnerable crops-during the quality-control process within the nest, and, moreover, that the foraging ants may then be deterred from further harvesting of ' Trichoderma -enriched' plants., Competing Interests: We declare that we have no competing interests.
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- 2017
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14. Can Handheld Thermal Imaging Technology Improve Detection of Poachers in African Bushveldt?
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Hart AG, Rolfe RN, Dandy S, Stubbs H, MacTavish D, MacTavish L, and Goodenough AE
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- Adult, Animals, Animals, Wild, Conservation of Natural Resources methods, Cost-Benefit Analysis, Double-Blind Method, Firearms, Humans, Infrared Rays, Male, Mobile Applications economics, Parks, Recreational, Random Allocation, South Africa, Computers, Handheld economics, Criminal Behavior, Endangered Species, Grassland, Human Activities, Thermography economics, Thermography instrumentation, Thermography methods
- Abstract
Illegal hunting (poaching) is a global threat to wildlife. Anti-poaching initiatives are making increasing use of technology, such as infrared thermography (IRT), to support traditional foot and vehicle patrols. To date, the effectiveness of IRT for poacher location has not been tested under field conditions, where thermal signatures are often complex. Here, we test the hypothesis that IRT will increase the distance over which a poacher hiding in African scrub bushveldt can be detected relative to a conventional flashlight. We also test whether any increase in effectiveness is related to the cost and complexity of the equipment by comparing comparatively expensive (22,000 USD) and relatively inexpensive (2000 USD) IRT devices. To test these hypotheses we employ a controlled, fully randomised, double-blind procedure to find a poacher in nocturnal field conditions in African bushveldt. Each of our 27 volunteer observers walked three times along a pathway using one detection technology on each pass in randomised order. They searched a prescribed search area of bushveldt within which the target was hiding. Hiding locations were pre-determined, randomised, and changed with each pass. Distances of first detection and positive detection were noted. All technologies could be used to detect the target. Average first detection distance for flashlight was 37.3 m, improving by 19.8 m to 57.1 m using LIRT and by a further 11.2m to 68.3m using HIRT. Although detection distances were significantly greater for both IRTs compared to flashlight, there was no significant difference between LIRT and HIRT. False detection rates were low and there was no significant association between technology and accuracy of detection. Although IRT technology should ideally be tested in the specific environment intended before significant investment is made, we conclude that IRT technology is promising for anti-poaching patrols and that for this purpose low cost IRT units are as effective as units ten times more expensive.
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- 2015
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15. Emerging opportunities and challenges for the future of reservoir computing.
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Yan, Min, Huang, Can, Bienstman, Peter, Tino, Peter, Lin, Wei, and Sun, Jie
- Abstract
Reservoir computing originates in the early 2000s, the core idea being to utilize dynamical systems as reservoirs (nonlinear generalizations of standard bases) to adaptively learn spatiotemporal features and hidden patterns in complex time series. Shown to have the potential of achieving higher-precision prediction in chaotic systems, those pioneering works led to a great amount of interest and follow-ups in the community of nonlinear dynamics and complex systems. To unlock the full capabilities of reservoir computing towards a fast, lightweight, and significantly more interpretable learning framework for temporal dynamical systems, substantially more research is needed. This Perspective intends to elucidate the parallel progress of mathematical theory, algorithm design and experimental realizations of reservoir computing, and identify emerging opportunities as well as existing challenges for large-scale industrial adoption of reservoir computing, together with a few ideas and viewpoints on how some of those challenges might be resolved with joint efforts by academic and industrial researchers across multiple disciplines. Reservoir Computing has shown advantageous performance in signal processing and learning tasks due to compact design and ability for fast training. Here, the authors discuss the parallel progress of mathematical theory, algorithm design and experimental realizations of Reservoir Computers, and identify emerging opportunities as well as existing challenges for their large-scale industrial adoption. [ABSTRACT FROM AUTHOR]
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- 2024
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16. Exploring the efficacy of identity priming and message framing in influencing American attitudes toward trophy hunting.
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Rozing, Eden, Rubino, Elena C., Turner, Amber, and Larasatie, Pipiet
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PUBLIC opinion ,ATTITUDE change (Psychology) ,AMERICAN attitudes ,SELF ,GROUP identity - Abstract
In the United States, the general public typically disapproves of trophy hunting. Given the global ubiquity of the practice, its potential to benefit conservation when properly managed, and the substantial role played by American hunter-tourists, changing these attitudes can help to maintain the practice as a wildlife management tool. Existing trophy hunting communications, which are currently neither well-designed nor widely distributed, are unable to effectively do so. We used an online survey to explore current American attitudes regarding trophy hunting and assess the efficacy of different messaging strategies in influencing these attitudes. Respondents were randomly sorted into nine treatment groups, each of which received both an identity-focused priming item (or lack thereof, as a control) and a message about trophy hunting. The priming items prompted respondents to consider either their personal values (personal identity) or political affiliation (social identity) before reading their assigned message. All three messages evaluated in this study contained a brief informative paragraph about trophy hunting, and additional information concerning either the ecological or socioeconomic benefits associated with the practice was appended onto this paragraph for respondents assigned to treatments featuring an experimental message frame. Based on the responses of 2000 U.S. residents, we found that negative attitudes regarding trophy hunting were pervasive and resistant to change. Messages framed around the ecological or socioeconomic benefits of managed trophy hunting slightly increased approval for the practice, but identity-focused priming items had no comparable effect. Additionally, respondents' trust in the messages varied by source. This research represents a novel approach to understanding and changing public attitudes toward a highly controversial form of hunting through scientifically informed messaging. While our findings suggest several areas of improvement specifically for future trophy hunting communications, they may also be applied to outreach efforts concerning other contentious wildlife management issues. [ABSTRACT FROM AUTHOR]
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- 2024
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17. Lifetime trajectories of male mating effort under reproductive conflict in a cooperatively breeding mammal.
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Birch, Graham, Nichols, Hazel J., Mwanguhya, Francis, Thompson, Faye J., Cant, Michael A., and Blount, Jonathan D.
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ANIMAL sexual behavior ,BIOLOGICAL evolution ,EXTERNALITIES ,BIOLOGICAL fitness ,ESTRUS - Abstract
The costs of reproductive conflict can shape the evolution of life-histories in animal societies. These costs may change as individuals age and grow, and with within-group competition. Social costs of reproductive conflict have been invoked to explain why females might gain from delaying maturity or ceasing reproduction midway through life, but not in males. Here, we analyse more than 20 years of data to understand how individual male banded mongooses adjust their reproductive activity in response to the costs of reproductive conflict. In banded mongoose groups, multiple female breeders enter oestrus synchronously that are each guarded by a single male that aggressively wards-off rivals. The heaviest males in the group gained the greatest share of paternity. Those lighter males that are reproductively active paid disproportionate survival costs, and by engaging in reproductive activity early had lower lifetime reproductive success. Our results suggest that reproductive inactivity early in life is adaptive, as males recoup any lost fitness by first growing before engaging in less costly and more profitable reproductive activity later in life. These results suggest that resource holding potential of males and the intensity of reproductive conflict interact to shape lifetime schedules of reproductive behaviour. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Applying palaeoecological analogues to contemporary challenges: community-level effects of canopy gaps caused by systematic decline of a prevalent tree species.
- Author
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Webb, Julia and Goodenough, Anne E.
- Abstract
Temperate woodland vegetation is initially determined by spatiotemporal and historical factors, mediated by complex biotic interactions. However, catastrophic events such as disease outbreaks (e.g., sweet chestnut blight, ash dieback), infestations of insect pests, and human-accelerated climate change can create canopy gaps due to systematic decline in, or loss of, tree species that was once an important part of the canopy. Resultant cascade effects have the potential to alter the composition of woodland ecosystems quickly and radically, but inherent lag times make primary research into these effects challenging. Here, we explore change in woodland vegetation at 10 sites in response to canopy opening using the Elm Decline, a rapid loss of Ulmus in woodlands across northwestern Europe ~ 5800 years ago that coexisted alongside other stressors such as increasing human activity, as a palaeoecological analogue. For arboreal taxa, community evenness significantly decreased, within-site turnover significantly increased, and richness remained unchanged. Changes in arboreal taxa were highly site-specific but there was a substantial decline in woody climbing taxa, especially Hedera (ivy), across the majority of sites. For shrub taxa, richness significantly increased but evenness and turnover remained consistent. Interestingly, however, there was a significant increase in abundance of shrubs at 70% of sites, including Calluna (heather), Ilex (holly) and Corylus (hazel), suggesting structural change. Surprisingly, there was no change in richness, evenness or turnover for herb taxa, possibly because change was highly variable spatially. However, there was a marked uptick in the disturbance indicator Plantago (plantain). Overall, these findings suggest that woodlands with sustained reduction in, or loss of, a tree species that once formed an important part of the canopy has profound, but often spatially idiosyncratic, impacts on vegetation diversity (richness), composition (evenness), stability (turnover), and on abundance of specific taxa, especially within the shrub layer. Use of this palaeoecological analogue, which was itself complicated by cooccurring changes in human activity, provides a valuable empirical insight into possible cascade effects of similar change in canopy opening in contemporary settings, including Ash Dieback. [ABSTRACT FROM AUTHOR]
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- 2024
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19. A potential risk and management of feces in the queenless ant.
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Ishizuka, Y., Yamashita, R., Itoh, H., Matsuura, Y., Kikuchi, Y., and Shimoji, H.
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Many ant species inhabit closed environments with limited spaces underground, encompassing a potential risk of pathogen reservoir and transmission among colony members. Despite accumulated research on the triggers of endemic outbreaks, the mechanism through which pathogenic microorganisms are introduced into ant colonies from outside the nest remains unclear. Waste materials could be one of the potential sources of pathogens, and we hypothesize that the feces of infected foragers may serve as a route of pathogen infiltration into the nest. In this study, we examined the transmission route and distribution pattern of an entomopathogenic bacterium, Pseudomonas entomophila, and ant behaviors in the nest using Diacamma cf. indicum from Japan. First, through infection experiments, we revealed that infected foragers introduce foreign pathogens into the nest via their feces, and the distribution of introduced pathogens within the nest shows a bias towards the midden room. Subsequently, our behavioral observations showed that reproductive individuals tend to remain in the other nest rooms. Overall, our results suggest that while the feces of infected foragers are potential reservoirs of disease outbreaks within a colony, such a risk might be mitigated by confining feces in a specific room of the ant nest. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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20. First populations of invasive red swamp crayfish flourish in Slovakia.
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Lipták, Boris, Prati, Sebastian, Oficialdegui, Francisco J., Apfelová, Mária, Pekárová, Stanislava, Kautman, Ján, Janský, Vladimír, and Kouba, Antonín
- Subjects
PROCAMBARUS clarkii ,ECOSYSTEM management ,HOT springs ,BIOLOGICAL invasions ,INTRODUCED species ,CRAYFISH - Abstract
The red swamp crayfish Procambarus clarkii is one of the most prominent invasive crayfish species in Europe. Here, we document the first recording of this species in Slovakia, including evidence of its occurrence in two natural localities, both fed by thermal springs. The first locality is near Turčianske Teplice in Central Slovakia, immediately downstream of a commercial culturing facility for aquatic ornamentals, while the other is located approximately 150 km southwards, close to Komárno. Both P. clarkii populations are well-established, with numerous individuals of both sexes, size classes, and ovigerous females. Although none of the 32 screened adult crayfish of either population tested positive for Aphanomyces astaci, the causative agent of the crayfish plague, its presence cannot be entirely excluded. So far, P. clarkii is confined to short stretches in both sites. However, its independent expansion into nearby watercourses can be expected. Despite the translocation of non-native species of Union concern, such as P. clarkii, being strictly forbidden, illegal human actions can facilitate their dispersal. Given the still relatively limited territory conquered by the invasive species in the two localities, urgent eradication and control measures were recently adopted. The ongoing eradication campaigns yielded thousands of P. clarkii individuals extracted from both localities in 2023. As thermal springs and thermally polluted waters are known hotspots of non-native and potentially invasive species, monitoring these sites is highly recommended. [ABSTRACT FROM AUTHOR]
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- 2024
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21. Foraging ants trade off further for faster: use of natural bridges and trunk trail permanency in carpenter ants.
- Author
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Loreto RG, Hart AG, Pereira TM, Freitas ML, Hughes DP, and Elliot SL
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- Animals, Time Factors, Ants physiology, Environment, Feeding Behavior physiology
- Abstract
Trail-making ants lay pheromones on the substrate to define paths between foraging areas and the nest. Combined with the chemistry of these pheromone trails and the physics of evaporation, trail-laying and trail-following behaviours provide ant colonies with the quickest routes to food. In relatively uniform environments, such as that provided in many laboratory studies of trail-making ants, the quickest route is also often the shortest route. Here, we show that carpenter ants (Camponotus rufipes), in natural conditions, are able to make use of apparent obstacles in their environment to assist in finding the fastest routes to food. These ants make extensive use of fallen branches, twigs and lianas as bridges to build their trails. These bridges make trails significantly longer than their straight line equivalents across the forest floor, but we estimate that ants spend less than half the time to reach the same point, due to increased carriage speed across the bridges. We also found that these trails, mainly composed of bridges, are maintained for months, so they can be characterized as trunk trails. We suggest that pheromone-based foraging trail networks in field conditions are likely to be structured by a range of potentially complex factors but that even then, speed remains the most important consideration.
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- 2013
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22. Using Long-Term Volunteer Records to Examine Dormouse (Muscardinusavellanarius) Nestbox Selection.
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Williams RL, Goodenough AE, Hart AG, and Stafford R
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- Animals, Birds, Data Collection, Ferns, Forests, Regression Analysis, Time Factors, Trees, United Kingdom, Volunteers, Choice Behavior, Myoxidae, Nesting Behavior
- Abstract
Within ecology, there are unanswered questions about species-habitat interactions, which could potentially be resolved by a pragmatic analysis of a long-term volunteer-collected dataset. Here, we analysed 18 years of volunteer-collected data from a UK dormouse nestbox monitoring programme to determine the influence of habitat variables on nestbox choice by common dormice (Muscardinusavellanarius). We measured a range of habitat variables in a coppiced woodland in Gloucestershire, UK, and analysed these in relation to dormouse nestbox occupancy records (by dormice, other small mammals, and birds) collected by volunteers. While some characteristics of the woodland had changed over 18 years, simple transformation of the data and interpretation of the results indicated that the dataset was informative. Using stepwise regressions, multiple environmental and ecological factors were found to determine nestbox selection. Distance from the edge of the wood was the most influential (this did not change over 18 years), with boxes in the woodland interior being selected preferentially. There was a significant negative relationship with the presence of ferns (indicative of damp shady conditions). The presence of oak (a long-lived species), and the clumped structural complexity of the canopy were also important factors in the final model. There was no evidence of competition between dormice and birds or other mammals. The results provide greater understanding of artificial dormouse nest-site requirements and indicate that, in terms of habitat selection, long-term volunteer-collected datasets contribute usefully to understanding the requirements of species with an important conservation status.
- Published
- 2013
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23. Regression with empirical variable selection: description of a new method and application to ecological datasets.
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Goodenough AE, Hart AG, and Stafford R
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- Animals, Birds, Databases, Factual, Models, Statistical, Ecology methods, Models, Biological, Regression Analysis
- Abstract
Despite recent papers on problems associated with full-model and stepwise regression, their use is still common throughout ecological and environmental disciplines. Alternative approaches, including generating multiple models and comparing them post-hoc using techniques such as Akaike's Information Criterion (AIC), are becoming more popular. However, these are problematic when there are numerous independent variables and interpretation is often difficult when competing models contain many different variables and combinations of variables. Here, we detail a new approach, REVS (Regression with Empirical Variable Selection), which uses all-subsets regression to quantify empirical support for every independent variable. A series of models is created; the first containing the variable with most empirical support, the second containing the first variable and the next most-supported, and so on. The comparatively small number of resultant models (n = the number of predictor variables) means that post-hoc comparison is comparatively quick and easy. When tested on a real dataset--habitat and offspring quality in the great tit (Parus major)--the optimal REVS model explained more variance (higher R(2)), was more parsimonious (lower AIC), and had greater significance (lower P values), than full, stepwise or all-subsets models; it also had higher predictive accuracy based on split-sample validation. Testing REVS on ten further datasets suggested that this is typical, with R(2) values being higher than full or stepwise models (mean improvement = 31% and 7%, respectively). Results are ecologically intuitive as even when there are several competing models, they share a set of "core" variables and differ only in presence/absence of one or two additional variables. We conclude that REVS is useful for analysing complex datasets, including those in ecology and environmental disciplines.
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- 2012
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24. Radiative improvement of the lattice nonrelativistic QCD action using the background field method and application to the hyperfine splitting of quarkonium states.
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Hammant TC, Hart AG, von Hippel GM, Horgan RR, and Monahan CJ
- Abstract
We present the first application of the background field method to nonrelativistic QCD (NRQCD) on the lattice in order to determine the one-loop radiative corrections to the coefficients of the NRQCD action in a manifestly gauge-covariant manner. The coefficients of the σ·B term in the NRQCD action and the four-fermion spin-spin interaction are computed at the one-loop level; the resulting shift of the hyperfine splitting of bottomonium is found to bring the lattice predictions in line with experiment.
- Published
- 2011
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25. A model capturing novel strand symmetries in bacterial DNA.
- Author
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Sobottka M and Hart AG
- Subjects
- Base Sequence, Markov Chains, Base Pairing, DNA, Bacterial chemistry, Models, Chemical
- Abstract
Chargaff's second parity rule for short oligonucleotides states that the frequency of any short nucleotide sequence on a strand is approximately equal to the frequency of its reverse complement on the same strand. Recent studies have shown that, with the exception of organellar DNA, this parity rule generally holds for double-stranded DNA genomes and fails to hold for single-stranded genomes. While Chargaff's first parity rule is fully explained by the Watson-Crick pairing in the DNA double helix, a definitive explanation for the second parity rule has not yet been determined. In this work, we propose a model based on a hidden Markov process for approximating the distributional structure of primitive DNA sequences. Then, we use the model to provide another possible theoretical explanation for Chargaff's second parity rule, and to predict novel distributional aspects of bacterial DNA sequences., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
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26. What prevents phenological adjustment to climate change in migrant bird species? Evidence against the "arrival constraint" hypothesis.
- Author
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Goodenough AE, Hart AG, and Elliot SL
- Subjects
- Adaptation, Physiological, Animals, Birds classification, Breeding, Germany, Netherlands, Species Specificity, Time Factors, Animal Migration physiology, Birds physiology, Climate Change, Conservation of Energy Resources
- Abstract
Phenological studies have demonstrated changes in the timing of seasonal events across multiple taxonomic groups as the climate warms. Some northern European migrant bird populations, however, show little or no significant change in breeding phenology, resulting in synchrony with key food sources becoming mismatched. This phenological inertia has often been ascribed to migration constraints (i.e. arrival date at breeding grounds preventing earlier laying). This has been based primarily on research in The Netherlands and Germany where time between arrival and breeding is short (often as few as 9 days). Here, we test the arrival constraint hypothesis over a 15-year period for a U.K. pied flycatcher (Ficedula hypoleuca) population where laying date is not constrained by arrival as the period between arrival and breeding is substantial and consistent (average 27 ± 4.57 days SD). Despite increasing spring temperatures and quantifiably stronger selection for early laying on the basis of number of offspring to fledge, we found no significant change in breeding phenology, in contrast with co-occurring resident blue tits (Cyanistes caeruleus). We discuss possible non-migratory constraints on phenological adjustment, including limitations on plasticity, genetic constraints and competition, as well as the possibility of counter-selection pressures relating to adult survival, longevity or future reproductive success. We propose that such factors need to be considered in conjunction with the arrival constraint hypothesis.
- Published
- 2011
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27. Eu-social science: the role of internet social networks in the collection of bee biodiversity data.
- Author
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Stafford R, Hart AG, Collins L, Kirkhope CL, Williams RL, Rees SG, Lloyd JR, and Goodenough AE
- Subjects
- Animals, Biodiversity, Cooperative Behavior, Ecosystem, Internet, Population Dynamics, Software, United Kingdom, Bees physiology, Conservation of Natural Resources, Data Collection, Social Support
- Abstract
Background: Monitoring change in species diversity, community composition and phenology is vital to assess the impacts of anthropogenic activity and natural change. However, monitoring by trained scientists is time consuming and expensive., Methodology/principal Findings: Using social networks, we assess whether it is possible to obtain accurate data on bee distribution across the UK from photographic records submitted by untrained members of the public, and if these data are in sufficient quantity for ecological studies. We used Flickr and Facebook as social networks and Flickr for the storage of photographs and associated data on date, time and location linked to them. Within six weeks, the number of pictures uploaded to the Flickr BeeID group exceeded 200. Geographic coverage was excellent; the distribution of photographs covered most of the British Isles, from the south coast of England to the Highlands of Scotland. However, only 59% of photographs were properly uploaded according to instructions, with vital information such as 'tags' or location information missing from the remainder. Nevertheless, this incorporation of information on location of photographs was much higher than general usage on Flickr (∼13%), indicating the need for dedicated projects to collect spatial ecological data. Furthermore, we found identification of bees is not possible from all photographs, especially those excluding lower abdomen detail. This suggests that giving details regarding specific anatomical features to include on photographs would be useful to maximise success., Conclusions/significance: The study demonstrates the power of social network sites to generate public interest in a project and details the advantages of using a group within an existing popular social network site over a traditional (specifically-designed) web-based or paper-based submission process. Some advantages include the ability to network with other individuals or groups with similar interests, and thus increasing the size of the dataset and participation in the project.
- Published
- 2010
- Full Text
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28. Evidence for contemporary evolution during Darwin's lifetime.
- Author
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Hart AG, Stafford R, Smith AL, and Goodenough AE
- Subjects
- Animals, History, 19th Century, Lepidoptera genetics, Pigmentation genetics, Selection, Genetic, United Kingdom, Biological Evolution
- Abstract
Darwin's On the Origin of Species[1] introduced the world to the most fundamental concept in biological sciences - evolution. However, in the 150 years following publication of his seminal work, much has been made of the fact that Darwin was missing at least one crucial link in his chain of evidence - he had no evidence for contemporary evolution through natural selection. Indeed, as one commentator noted on the centenary of the publication of Origin, "Had Darwin observed industrial melanism he would have seen evolution occurring not in thousands of years but in thousands of days - well within his lifetime. He would have witnessed the consummation and confirmation of his life's work"[2].
- Published
- 2010
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29. Density-dependent prophylactic immunity reconsidered in the light of host group living and social behavior.
- Author
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Elliot SL and Hart AG
- Subjects
- Animals, Population Density, Ecosystem, Invertebrates immunology, Models, Biological, Social Behavior
- Abstract
According to the density-dependent hypothesis (DDP), hosts living at high densities suffer greater risk of disease and so invest more in immunity. Although there is much empirical support for this, especially from invertebrate systems, there are many exceptions, notably in social insects. We propose that (A) density is not always the most appropriate population parameter to use when considering the risks associated with disease and (B) behavioral defenses should be given a greater emphasis in considerations of a host's repertoire of immune defenses. We propose a complementary framework stressing the connectivity between and within populations as a starting point and emphasizing the costs represented by disease above the risk of disease per se. We consider the components of immune defense and propose that behaviors may represent lower-cost defenses than their physiological counterparts. As group-living and particularly social animals will have a greater behavioral repertoire, we conclude that with group living comes a greater capacity for behavioral immune defense, most particularly for social insects. This may escape our notice if we consider physiological parameters alone.
- Published
- 2010
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30. Hygienic behavior in the stingless bees Melipona beecheii and Scaptotrigona pectoralis (Hymenoptera: Meliponini).
- Author
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Medina LM, Hart AG, and Ratnieks FL
- Subjects
- Animals, Bees physiology, Behavior, Animal
- Abstract
Hygienic behavior, a trait that may confer resistance to brood diseases in the honey bee Apis mellifera, was studied in two species of stingless bees in Mexico. Eight colonies each of Melipona beecheii and Scaptotrigona pectoralis were tested for hygienic behavior, the removal of dead or diseased brood, by freeze killing a comb of sealed cells containing pupae. Both species detected and removed dead brood. However, removal rates differed between species. In M. beecheii colonies, workers took 2-9 days to remove 100% of the dead brood (4.4 +/- 2.0 days, mean +/- SD), while S. pectoralis removed all dead brood in less than 3 days (2.3 +/- 0.6 days, mean +/- SD). We conclude that hygienic behavior is not unique to A. mellifera, and is not solely an adaptation for the reuse of brood cells as occurs in honey bees but not stingless bees. Although stingless bees do not reuse brood cells, space is limited. The removal of dead brood may be necessary to allow new cells to be constructed in the same place.
- Published
- 2009
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31. Emerging technologies in citizen science and potential for insect monitoring.
- Author
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Sheard, Julie Koch, Adriaens, Tim, Bowler, Diana E., Büermann, Andrea, Callaghan, Corey T., Camprasse, Elodie C. M., Chowdhury, Shawan, Engel, Thore, Finch, Elizabeth A., von Gönner, Julia, Hsing, Pen-Yuan, Mikula, Peter, Rachel Oh, Rui Ying, Peters, Birte, Phartyal, Shyam S., Pocock, Michael J. O., Wäldchen, Jana, and Bonn, Aletta
- Subjects
TECHNOLOGICAL innovations ,CITIZEN science ,BIODIVERSITY monitoring ,INSECTS - Abstract
Emerging technologies are increasingly employed in environmental citizen science projects. This integration offers benefits and opportunities for scientists and participants alike. Citizen science can support large-scale, long-term monitoring of species occurrences, behaviour and interactions. At the same time, technologies can foster participant engagement, regardless of pre-existing taxonomic expertise or experience, and permit new types of data to be collected. Yet, technologies may also create challenges by potentially increasing financial costs, necessitating technological expertise or demanding training of participants. Technology could also reduce people's direct involvement and engagement with nature. In this perspective, we discuss how current technologies have spurred an increase in citizen science projects and how the implementation of emerging technologies in citizen science may enhance scientific impact and public engagement. We show how technology can act as (i) a facilitator of current citizen science and monitoring efforts, (ii) an enabler of new research opportunities, and (iii) a transformer of science, policy and public participation, but could also become (iv) an inhibitor of participation, equity and scientific rigour. Technology is developing fast and promises to provide many exciting opportunities for citizen science and insect monitoring, but while we seize these opportunities, we must remain vigilant against potential risks. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
32. Towards a toolkit for global insect biodiversity monitoring.
- Author
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van Klink, Roel, Sheard, Julie Koch, Høye, Toke T., Roslin, Tomas, Do Nascimento, Leandro A., and Bauer, Silke
- Subjects
BIODIVERSITY monitoring ,INSECT ecology ,INSECTS ,ENVIRONMENTAL monitoring ,POPULATION ecology ,COMPUTER vision - Abstract
Insects are the most diverse group of animals on Earth, yet our knowledge of their diversity, ecology and population trends remains abysmally poor. Four major technological approaches are coming to fruition for use in insect monitoring and ecological research—molecular methods, computer vision, autonomous acoustic monitoring and radar-based remote sensing—each of which has seen major advances over the past years. Together, they have the potential to revolutionize insect ecology, and to make all-taxa, fine-grained insect monitoring feasible across the globe. So far, advances within and among technologies have largely taken place in isolation, and parallel efforts among projects have led to redundancy and a methodological sprawl; yet, given the commonalities in their goals and approaches, increased collaboration among projects and integration across technologies could provide unprecedented improvements in taxonomic and spatio-temporal resolution and coverage. This theme issue showcases recent developments and state-of-the-art applications of these technologies, and outlines the way forward regarding data processing, cost-effectiveness, meaningful trend analysis, technological integration and open data requirements. Together, these papers set the stage for the future of automated insect monitoring. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Boosting biodiversity monitoring using smartphone-driven, rapidly accumulating community-sourced data.
- Author
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Keisuke Atsumi, Yuusuke Nishida, Masayuki Ushio, Hirotaka Nishi, Takanori Genroku, and Shogoro Fujiki
- Published
- 2024
- Full Text
- View/download PDF
34. Ethical implications of defining longstanding anorexia nervosa.
- Author
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Voswinkel, Marthe M., Hanegraaff, Simone M., Mares, Suzanne H.W., Wezenberg, Elke, van Delden, Johannes J.M., and van Elburg, Annemarie A.
- Subjects
ANOREXIA nervosa ,EATING disorders ,SCIENTIFIC literature ,ETHICAL problems ,INFORMATION sharing - Abstract
The label severe and enduring anorexia nervosa (SE-AN) is widely used in the literature on longstanding anorexia nervosa (AN). However, the process of constructing the criteria and the use of the label SE-AN has ethical implications that have not been taken into account. Through combining existing literature and lived experience perspective, this paper addresses to what extent the current criteria do and do not reflect the lived experience. Arguments are presented on why the process of constructing the criteria for SE-AN and the application of the label can be both identified as, and give rise to, epistemic injustice. Epistemic injustice is an injustice that is done to a person as an individual with the capacity of acquiring and sharing knowledge. This type of injustice can occur at any stage of an interaction between people in which knowledge is shared with one another. The paper concludes by giving suggestions on how to pursue epistemic justice in the process of defining longstanding AN. Plain English summary: Some patients with anorexia nervosa (AN) develop a longstanding eating disorder. Over the years different labels, such as 'chronic AN' or 'treatment resistant AN', have been used to describe longstanding AN. Currently, the label that is used most often in scientific literature is 'severe and enduring AN' (SE-AN) and criteria for what entails SE-AN have been proposed. This paper looks at the possible ethical issues that have arisen in the process of constructing the criteria and possible ethical problems that may result from using the label SE-AN. The paper focuses on injustice that may arise when people with specific experiences, such as lived experience of longstanding AN, are not acknowledged as people with important knowledge to share. The paper concludes by giving suggestions on how to overcome this type of injustice. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Mortality rates and division of labor in the leaf-cutting ant, Atta colombica.
- Author
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Brown MJ, Bot AN, and Hart AG
- Subjects
- Animals, Ants physiology, Mortality
- Abstract
Division of labor in social groups is affected by the relative costs and benefits of conducting different tasks. However, most studies have examined the dynamics of division of labor, rather than the costs and benefits that presumably underlie the evolution of such systems. In social insects, division of labor may be simplistically described as a source-sink system, with external tasks, such as foraging, acting as sinks for the work force. The implications of two distinct sinks - foraging and waste-heap working - for division of labor were examined in the leaf-cutting ant Atta colombica. Intrinsic mortality rates were similar across external task groups. Exposure to waste (a task-related environment) led to a 60% increase in the mortality rate of waste-heap workers compared to workers not exposed to waste. Given the small number of workers present in the waste-heap task group, such increases in mortality are unlikely to affect division of labor and task allocation dramatically, except perhaps under conditions of stress.
- Published
- 2006
- Full Text
- View/download PDF
36. A test of worker policing theory in an advanced eusocial wasp, Vespula rufa.
- Author
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Wenseleers T, Badcock NS, Erven K, Tofilski A, Nascimento FS, Hart AG, Burke TA, Archer ME, and Ratnieks FL
- Subjects
- Animals, England, Female, Gene Frequency, Male, Microsatellite Repeats genetics, Observation, Ovum, Reproduction physiology, Models, Biological, Sexual Behavior, Animal physiology, Social Dominance, Wasps physiology
- Abstract
Mutual policing is an important mechanism for maintaining social harmony in group-living organisms. In some ants, bees, and wasps, workers police male eggs laid by other workers in order to maintain the reproductive primacy of the queen. Kin selection theory predicts that multiple mating by the queen is one factor that can selectively favor worker policing. This is because when the queen is mated to multiple males, workers are more closely related to queen's sons than to the sons of other workers. Here we provide an additional test of worker policing theory in Vespinae wasps. We show that the yellowjacket Vespula rufa is characterized by low mating frequency, and that a significant percentage of the males are workers' sons. This supports theoretical predictions for paternities below 2, and contrasts with other Vespula species, in which paternities are higher and few or no adult males are worker produced, probably due to worker policing, which has been shown in one species, Vespula vulgaris. Behavioral observations support the hypothesis that V. rufa has much reduced worker policing compared to other Vespula. In addition, a significant proportion of worker-laid eggs were policed by the queen.
- Published
- 2005
37. Crossing the taxonomic divide: conflict and its resolution in societies of reproductively totipotent individuals.
- Author
-
Hart AG and Ratnieks FL
- Subjects
- Aggression physiology, Animals, Ants physiology, Mole Rats physiology, Sexual Behavior, Animal physiology, Sociobiology, Hierarchy, Social, Models, Biological, Ploidies, Reproduction physiology, Social Behavior
- Abstract
Reproduction in groups may be unequal, with one or a few individuals monopolizing direct reproduction assisted by nonbreeding helpers. In social insects this has frequently led to a pronounced queen-worker dichotomy and a loss of reproductive totipotency among workers. However, in some invertebrate and all vertebrate societies, all or most individuals remain reproductively totipotent. In these groups, conflicts of interest over reproduction are potentially greatest. Here, we synthesize previous analyses of reproductive conflict, aggression and breeder replacement in haplodiploid societies of totipotent individuals and extend them to cover diploid (vertebrate) examples. We test predictions arising from this approach using the best-studied invertebrate (Dinoponera queenless ants) and vertebrate (naked mole-rat, Heterocephalus glaber) examples, although in principle our analysis applies to all similar groups. We find that premature replacement of a parent breeder by nonbreeders (overthrow) is rare. Dominant coercive control of nonbreeders by the breeder is often unnecessary and honest signalling of breeder vitality can maintain group stability and resolve conflicts over reproduction. We hope that by providing an explicit transfer of social theory between ants and naked mole-rats we will stimulate further cross-taxonomic studies that will greatly broaden our understanding of sociality.
- Published
- 2005
- Full Text
- View/download PDF
38. When Resistance Is Useless: Policing and the Evolution of Reproductive Acquiescence in Insect Societies.
- Author
-
Wenseleers T, Hart AG, and Ratnieks FLW
- Abstract
In social groups composed of kin, inclusive fitness benefits can favor greater cooperation. Alternatively, cooperation can be enforced through the policing of less cooperative individuals. Here, we show that the effect of policing can be twofold: not only can it directly suppress individual selfishness, it can also entirely remove the incentive for individuals to act selfishly in the first place. We term such individual restraint in response to socially imposed policing "acquiescence" and illustrate the concept using examples drawn from the social Hymenoptera (the ants, bees, and wasps). Inclusive fitness models confirm that when a policing system is in place, individuals should be less tempted to act selfishly. This is shown to have important consequences for the resolution of conflict within their societies. For example, it can explain why in many species very few workers attempt to reproduce and why immature females usually do not attempt to develop as queens rather than workers. Although our analyses are primarily focused on the social insects, our conclusions are likely to be general and to apply to other societies as well.
- Published
- 2004
- Full Text
- View/download PDF
39. If you can lose a driving licence, why not a PhD?
- Author
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Hart AG
- Subjects
- Germany, Education, Graduate standards, Research Personnel ethics, Research Personnel standards, Scientific Misconduct legislation & jurisprudence, Universities standards
- Published
- 2004
- Full Text
- View/download PDF
40. Partial nectar loads as a cause of multiple nectar transfer in the honey bee (Apis mellifera): a simulation model.
- Author
-
Gregson AM, Hart AG, Holcombe M, and Ratnieks FL
- Subjects
- Adaptation, Psychological, Animals, Cooperative Behavior, Bees physiology, Behavior, Animal, Models, Psychological
- Abstract
Honey bee foragers transfer their nectar loads to receiver bees within the nest. Surprisingly, they often transfer to more than one receiver (published values range from 1.9 to 2.7). Several adaptive hypotheses have been proposed to explain why multiple transfer occurs. One hypothesis, information improvement, states that multiple transfer arises as an adaptive forager-driven process. Foragers use the delay in finding a receiver to assess the relative work capacities of foragers and receivers, performing recruitment dances when appropriate. Multiple transferring improves their delay information. We used a stochastic simulation model to investigate the non-adaptive partial loads hypothesis. We determined the extent to which partial crop loads and receiver filling and emptying rules (i.e. how much nectar to accept before leaving the transfer area) can cause multiple transfer. As many as 1.9 nectar transfers per returning forager were generated within biologically realistic parameter space. We suggest that much multiple transfer arises as a non-adaptive consequence of partitioning nectar foraging between foragers and receivers, but that this will also result in foragers having better information about the relative work capacities of foragers and receivers as a useful consequence. We suggest that the number of transfers caused by partial loads could also be increased by an adaptive forager-driven effort to improve their information concerning the balance of foragers and receivers and we outline a framework wherein the information improvement hypothesis can be directly tested.
- Published
- 2003
- Full Text
- View/download PDF
41. Magnetic resonance imaging in entomology: a critical review.
- Author
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Hart AG, Bowtell RW, Köckenberger W, Wenseleers T, and Ratnieks FL
- Subjects
- Animals, Insecta parasitology, Insecta anatomy & histology, Insecta physiology, Magnetic Resonance Imaging methods
- Abstract
Magnetic resonance imaging (MRI) enables in vivo imaging of organisms. The recent development of the magnetic resonance microscope (MRM) has enabled organisms within the size range of many insects to be imaged. Here, we introduce the principles of MRI and MRM and review their use in entomology. We show that MRM has been successfully applied in studies of parasitology, development, metabolism, biomagnetism and morphology, and the advantages and disadvantages relative to other imaging techniques are discussed. In addition, we illustrate the images that can be obtained using MRM. We conclude that although MRM has significant potential, further improvements to the technique are still desirable if it is to become a mainstream imaging technology in entomology.
- Published
- 2003
42. A colony-level response to disease control in a leaf-cutting ant.
- Author
-
Hart AG, Bot AN, and Brown MJ
- Subjects
- Animals, Ants physiology, Social Behavior, Ants pathogenicity, Ascomycota pathogenicity, Plant Diseases microbiology, Plant Leaves microbiology
- Abstract
Parasites and pathogens often impose significant costs on their hosts. This is particularly true for social organisms, where the genetic structure of groups and the accumulation of contaminated waste facilitate disease transmission. In response, hosts have evolved many mechanisms of defence against parasites. Here we present evidence that Atta colombica, a leaf-cutting ant, may combat Escovopsis, a dangerous parasite of Atta's garden fungus, through a colony-level behavioural response. In A. colombica, garden waste is removed from within the colony and transported to the midden--an external waste dump--where it is processed by a group of midden workers. We found that colonies infected with Escovopsis have higher numbers of workers on the midden, where Escovopsis is deposited. Further, midden workers are highly effective in dispersing newly deposited waste away from the dumping site. Thus, the colony-level task allocation strategies of the Atta superorganism may change in response to the threat of disease to a third, essential party.
- Published
- 2002
- Full Text
- View/download PDF
43. Leaf caching in Atta leafcutting ants: discrete cache formation through positive feedback.
- Author
-
Hart AG and Ratnieks FL
- Abstract
We examined the occurrence, mechanism and costs and benefits of leaf caching in laboratory colonies of two species of leafcutting ants, Atta cephalotes and A. colombica. If foragers returning to the nest are unable to enter because of a temporary bottleneck caused by leaves building up they may deposit their leaf pieces outside the nest entrance, forming a leaf cache. Similar leaf caches occur in the field at foraging trail junctions, obstacles on the trail and within nest entrance tunnels. Foraging ants carrying leaves were presented with different-sized leaf caches and the number dropping their leaves on the cache was recorded. The probability of a forager dropping her leaf was positively correlated with the size of the cache that she encountered. Therefore, positive feedback played a role in the formation of nest entrance caches. Cached pieces were more likely to be retrieved than noncached pieces but the time taken to retrieve leaf pieces from a cache was greater than from scattered groups of leaves. We suggest that the strategy of flexible nest entrance caching is an adaptive response to fluctuating food availability and collection. Copyright 2000 The Association for the Study of Animal Behaviour.
- Published
- 2000
- Full Text
- View/download PDF
44. Citizens can help to map putative transmission sites for snail-borne diseases.
- Author
-
Tumusiime, Julius, Valderrama Bhraunxs, Noelia, Kagoro-Rugunda, Grace, Namirembe, Daisy, Albrecht, Christian, Twongyirwe, Ronald, Tolo, Casim Umba, Jacobs, Liesbet, and Huyse, Tine
- Subjects
COMMUNITY involvement ,BIOMPHALARIA ,DISEASE eradication ,MOBILE apps ,PREVENTIVE medicine ,TREMATODA ,CLASSICAL swine fever - Abstract
Introduction: Schistosomiasis and fasciolosis are snail-borne diseases of great medical and veterinary health importance. The World Health Organization recommends complementing drug treatment with snail control and community involvement for disease elimination, but there is a general lack of snail experts and hence snail distribution data. Therefore, we adopted a citizen science approach and involved citizens in the monitoring of medically and veterinary important snail taxa. Materials and methods: Snail data was collected weekly by 25 trained citizen scientists (CSs) at 76 sites around southern Lake Albert (Uganda) for 20 months. At each site, snails were searched for 30 minutes, sorted, target snail hosts identified to genus level, counted and data submitted through a smartphone application. The quality of this data was assessed by comparing it to monthly data collected by an 'expert' malacologist using the same sampling protocol. Generalised binomial logistic and linear mixed-effects models were used to analyse the variables for agreement between the CSs and expert. Findings: The binary agreement in presence/absence of Biomphalaria, Bulinus and Radix snails reported by the expert and CSs ranged between 70% and 86% (900 reports) with an average of 17% false negatives (sites wrongly defined as snail-free). The agreement for Biomphalaria and Radix increased with snail abundance, and false negatives decreased when the number of snails collected by citizens was aggregated per month. Site type significantly predicted binary agreement, which was lowest at lake sites (55%) and highest at spring sites (99%) with variations across genera. Similar temporal trends in snail abundance were recorded despite the expert reporting higher abundance. However, the relative abundance was consistent across site types. The match between the sites with highest Biomphalaria spp. abundance identified by CSs and expert was consistently high (~84.1%) and increased over time. Conclusions and recommendations: Our results demonstrate the potential of citizen science to map putative schistosomiasis transmission sites. We therefore argue that this inclusive, powerful and cost-effective approach can be more sustainable than top-down monitoring and intervention campaigns. Author summary: Schistosomiasis is a snail-borne disease of great public health importance. Since drug treatment does not suffice to control the disease, the World Health Organisation now recommends including snail control and community involvement. Here we demonstrate how local inhabitants of an endemic region, after training, can detect snail populations with acceptable accuracy, at significantly lower cost. This citizen science approach could therefore generate unprecedented datasets in terms of spatiotemporal resolution and coverage. Moreover, it empowers communities and increases knowledge on snail-borne diseases and their control and prevention. We therefore argue that this community-based approach presents a valuable and sustainable compliment to classical surveillance programs, especially in remote areas, thereby generating the much-anticipated data and community support for targeted snail control. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
45. Ant identity determines the fungi richness and composition of a myrmecochorous seed.
- Author
-
Fernandes, Tiago V., Fernandes, Otavio L., Gomes, Inácio J. M. T., Solar, Ricardo R. C., and Campos, Ricardo I.
- Subjects
COMPOSITION of seeds ,ANTS ,SEED dispersal ,FUNGAL communities ,GERMINATION ,CONTRAST effect ,SEEDS - Abstract
Myrmecochory—seed dispersal by ants—is a mutualistic interaction in which ants attracted by seed appendices take them away from the parental plant location, where seeds usually have better development odds. Not all ant species benefit plants, and the mechanisms of those divergent outcomes are still unclear, especially from the perspective of microbial third parties. Here, we explore the effects of seed manipulation on fungi communities promoted by two ant species with contrasting effects on seed germination and antimicrobial cleaning strategies. We hypothesize that: i) fungi richness is higher in seeds manipulated by Acromyrmex subterraneus (species that negatively affect seed germination), followed by unmanipulated seeds and seeds manipulated by Atta sexdens (ant species that increase seed germination) and ii) seeds manipulated by A. sexdens, Ac. subterraneus and unmanipulated seeds present dissimilar fungi compositions. We identified fungal morphotypes in three groups of seeds: i) manipulated by A. sexdens; ii) manipulated by Ac. subterraneus; iii) unmanipulated. Seeds manipulated by Ac. subterraneus exhibited higher fungal richness than those manipulated by A. sexdens and unmanipulated seeds, indicating that the ant species known to impair germination increases the fungal load on seeds. Additionally, we found that A. sexdens ants were unable to reduce fungal richness compared to unmanipulated seeds. Furthermore, fungal composition differed among all three treatments. Our results underscore the significance of ant species identity in shaping the fungal communities associated with myrmecochorous seeds. Given the potential influence of microbial infection on seed fate, we suggest considering manipulation strategies when evaluating the overall quality of an ant as a seed disperser. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
46. The interplay between leaf-cutter ants behaviour and social organization.
- Author
-
Khayat, Rana O.
- Abstract
Leaf-cutter ants (Atta and Acromyrmex species) exhibit complex social organizations that have fascinated scientists for decades. The leaf-cutter ants belong to a subgroup of fungus-growing ants, which live with fungus inside their nests. The behaviours exhibited by these ants are closely linked to their social organization, which involves intricate division of labour, caste systems, and cooperative tasks. This review article provides an overview of the behaviors associated with the social organization of leaf-cutter ants. It explores various aspects of their social organization, including foraging behavior, hitchhiking behaviour, hygienic behaviour, social organization and environmental influences. The leaf cutter ants have the instinct to forage, as they walk around the nest to cut leaf fragments from plants, then transport those fragments with their jaws and go back to the nest to cultivate a special fungus garden within the colony. By synthesizing existing knowledge, this review highlights the intricate relationships between behaviors and the social structure of leaf-cutter ants, shedding light on the underlying mechanisms and evolutionary implications. Furthermore, it identifies research gaps and proposes future directions for studying leaf-cutter ant behaviors, including emerging techniques and interdisciplinary approaches. The behaviors correlating with the social organization of leaf-cutter ants showcase the intricate mechanisms underlying their highly organized societies. In conclusion, this review contributes to our understanding of the fascinating behaviors exhibited by leaf-cutter ants and their implications in the broader context of social insect societies. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
47. Public perceptions of trophy hunting are pragmatic, not dogmatic.
- Author
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Hare, Darragh, Dickman, Amy J., Johnson, Paul J., Rono, Betty J., Mutinhima, Yolanda, Sutherland, Chris, Kulunge, Salum, Sibanda, Lovemore, Mandoloma, Lessah, and Kimaili, David
- Subjects
PUBLIC opinion ,WILDLIFE conservation ,HUNTING ,AFRICAN animals ,PREDATION - Abstract
Fierce international debates rage over whether trophy hunting is socially acceptable, especially when people from the Global North hunt well-known animals in sub-Saharan Africa. We used an online vignette experiment to investigate public perceptions of the acceptability of trophy hunting in sub-Saharan Africa among people who live in urban areas of the USA, UK and South Africa. Acceptability depended on specific attributes of different hunts as well as participants' characteristics. Zebra hunts were more acceptable than elephant hunts, hunts that would provide meat to local people were more acceptable than hunts in which meat would be left for wildlife, and hunts in which revenues would support wildlife conservation were more acceptable than hunts in which revenues would support either economic development or hunting enterprises. Acceptability was generally lower among participants from the UK and those who more strongly identified as an animal protectionist, but higher among participants with more formal education, who more strongly identified as a hunter, or who would more strongly prioritize people over wild animals. Overall, acceptability was higher when hunts would produce tangible benefits for local people, suggesting that members of three urban publics adopt more pragmatic positions than are typically evident in polarized international debates. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
48. Why the COVID-19 Crisis Is an Ethical Issue for Business: Evidence from the Australian JobKeeper Initiative.
- Author
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Corral de Zubielqui, Graciela and Harris, Howard
- Subjects
EMPLOYMENT subsidies ,COVID-19 pandemic ,BUSINESS ethics ,ETHICAL decision making ,COVID-19 ,SOCIAL pressure - Abstract
The COVID-19 virus was unveiled to the world as a health crisis and later also as an economic crisis. For some organisations, it has become an ethical crisis. This is certainly the case for large organisations in Australia, where the way many enterprises handled a government wage subsidy called JobKeeper led to a public backlash, media pressure, and a variety of responses ranging from 'We acted legally' to the full return of the subsidy. Some organisations later reported profits, and the public response indicated concern about this behaviour, many considering it immoral despite it being legally compliant. It is, we contend, a question to which stakeholder theory can be applied, examining how organisations view and respond to the public. We use content analysis of mainstream media to provide information about public reactions and information from official sources to confirm corporate action. We show that there is a significant ethical component in the public response to the behaviour of organisations as they respond to the crisis. COVID has been an ethical, health, and financial crisis for these organisations. Public pressure, exerted in and through the media, made the general public a definite stakeholder. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
49. Bee-Ing positive about wasp-negative media reporting: the opinions of scientists and their influence on the media.
- Author
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Oi, C. A., Brown, R. L., and Sumner, S.
- Abstract
Insects are the most diverse group on earth, providing a vast array of essential functions for people and nature. Yet, our appreciation of their contributions is biased towards a few economically important taxa, especially pollinating insects like honeybees. Other taxa are less well appreciated despite the important roles they play, and these taxa are rarely (if ever) the focus of conservation initiatives. Here, we explore the role that scientists play through their interactions with the media in shaping our attitudes towards one of the least appreciated insects—the aculeate (stinging) wasps. Vespine wasps are an excellent taxonomic group for such a study as they are important predators in native ecosystems (e.g., the Northern Hemisphere—in Europe and North America) but ecologically devastating as invasive species in many regions of the Southern Hemisphere (e.g., New Zealand, Australia, South America). Despite this, global media coverage of wasps invariably focuses on and emotively exaggerates the negative defensive stinging behaviour of wasps, and almost entirely overlooks their beneficial positive roles (as pest controllers and pollinators). Wasp and bee scientists from around the world were surveyed about their interactions with the media and how they considered these interactions to influence public perceptions and insect conservation. Our surveys capture the negative-wasp and positive-bee biases experienced by scientists through their interactions with the media. We consider the implications of such biases on wasp populations, their conservation and management, and make recommendations for a more balanced portrayal of this important and diverse group of insects. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
50. Disturbance-diversity relationships of microbial communities change based on growth substrate.
- Author
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Hoang, Don Q., Wilson, Lindsay R., Scheftgen, Andrew J., Suen, Garret, and Currie, Cameron R.
- Published
- 2024
- Full Text
- View/download PDF
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