Search

Raw data of video footage Abstract: Insects evolved various specialized mouthparts. We present an exemplary study on the mouthparts of adultAnax imperator, one of the largest odonates found in Central Europe.Like all adult dragonflies,A. imperatorpossesses carnivorous-type of biting-chewing mouthparts.To gain insights into the feeding process, behaviour and kinematics, living specimens were filmed during feeding using synchronized high-speed videography. Additionally, the maximum angles of movement were measured using a measuring microscope and combined with data from micro-computed tomography (µCT). The resulting visualizations of the 3D-geometry of each mouthpart were used to study their anatomy and complement the only descriptive knowledge of muscles inA. imperatorto date. Furthermore, CLSM-projections allow for estimation of differences in the material composition of the mouthparts' cuticle. By combining all methods, we can highlight possible functions and underlying biomechanics of each mouthpart. With regards to behavior, we analyzed the concerted movements of the mouthparts; two different types of cyclical feeding behavior were observed, which we refer to as “biting” and “chewing” throughout this study. Unique behavior of the mouthparts during feeding is active participation by the labrum and distinct movement by the maxillary laciniae. We aim to elucidate the complex movements of the mouthparts and their functioning by combining detailed information on (1)in vivomovement behavior (supplemented with physiological angle approximations), (2) movement ability provided by morphology (morphological movement angles), (3) 3D-anatomy, and (4) cuticle composition estimates. Furthermore, we present a study design that interlinks multiple methods for broad scale comparative studies in insects. This may allow for biomechanical and functional comparison of different eco-types of biting-chewing mouthparts in insects with varying food preferences and feeding habits. However, our approach only represents a starting point that can and should be further optimized and enhanced.

Recent climate and land-use changes are having substantial impacts on biodiversity, including population declines, range shifts, and changes in community composition. However, few studies have compared these impacts among multiple taxa, particularly because of a lack of standardized time series data over long periods. Existing data sets are typically of low resolution or poor coverage, both spatially and temporally, thereby limiting the inferences that can be drawn from such studies. Here, we compare climate and land-use driven occupancy changes in butterflies, grasshoppers, and dragonflies using an extensive data set of highly heterogeneous observation data collected in the central European region of Bavaria (Germany) over a 40-year period. Using occupancy models, we find occupancies (the proportion of sites occupied by a species in each year) of 37% of species have decreased, 30% have increased and 33% showed no significant trend. Butterflies and grasshoppers show strongest declines with 41% of species each. By contrast, 52% of dragonfly species increased. Temperature preference and habitat specificity appear as significant drivers of species trends. We show that cold-adapted species across all taxa have declined, whereas warm-adapted species have increased. In butterflies, habitat specialists have decreased, while generalists increased or remained stable. The trends of habitat generalists and specialists both in grasshoppers and semi-aquatic dragonflies, however did not differ. Our findings indicate strong and consistent effects of climate warming across insect taxa. The decrease of butterfly specialists could hint towards a threat from land-use change, as especially butterfly specialists' occurrence depends mostly on habitat quality and area. Our study not only illustrates how these taxa showed differing trends in the past but also provides hints on how we might mitigate the detrimental effects of human development on their diversity in the future.Jüngste Klima- und Landnutzungsänderungen haben erhebliche Auswirkungen auf die biologische Vielfalt, wie z. B. Populationsrückgänge, Verlagerung von Verbreitungsgebieten sowie Veränderungen in der Zusammensetzung von Lebensgemeinschaften. Nur wenige Studien bisher haben diese Auswirkungen auf unterschiedliche Taxa verglichen, insbesondere in Ermangelung an standardisierten Zeitreihendaten über lange Zeiträume. Vorhandene Datensätze sind räumlich und zeitlich oft wenig umfangreich, was Rückschlüsse, die aus solchen Studien gezogen werden können, einschränkt. Hier vergleichen wir klimatisch und landnutzungsbedingte Vorkommensänderungen bei Schmetterlingen, Heuschrecken und Libellen anhand eines umfangreichen Datensatzes mit sehr heterogenen Beobachtungsdaten, die in der mitteleuropäischen Region Bayern (Deutschland) über einen Zeitraum von 40 Jahren gesammelt wurden. Anhand von Occupancy-Modellen stellten wir fest, dass die Occupancy (Anteil der von einer Art besetzten Standorte pro Jahr) bei 37% der Arten abnahm, bei 30% zunahm und bei 33% keinen signifikanten Trend zeigte. Schmetterlinge und Heuschrecken wiesen mit jeweils 41% der Arten die stärksten Rückgänge auf. Dagegen nahmen 52% der Libellenarten zu. Temperaturpräferenz und Habitatspezifität scheinen die wichtigsten Faktoren für die Trendentwicklungen der Arten zu sein. Wir zeigen, dass kälteangepasste Arten in allen Taxa zurückgingen, während wärmeangepasste Arten zunahmen. Darüber hinaus nahmen bei Schmetterlingen Lebensraumspezialisten ab, während Generalisten zunahmen oder stabil blieben. Unsere Ergebnisse deuten auf starke und konsistente Auswirkungen der Klimaerwärmung auf alle untersuchten Insektentaxa hin. Der Rückgang von Schmetterlingsspezialisten (im Gegensatz zu den semiaquatischen Libellen, bei denen sowohl Generalisten als auch Spezialisten zunahmen) könnte auf eine Bedrohung in terrestrischen Lebensräumen hindeuten, da das Vorkommen insbesondere von Schmetterlingsspezialisten hauptsächlich von der Lebensraumqualität und -fläche abhängt. Beides hat sich in den letzten Jahrzehnten in aquatischen Lebensräumen verbessert, nicht jedoch in terrestrischen Lebensräumen. Unsere Studie veranschaulicht, warum diese Taxa in der Vergangenheit unterschiedliche Trends aufwiesen, und wie wir die nachteiligen Auswirkungen anthropogener Aktivitäten auf ihre Vielfalt in Zukunft abmildern können.

Research Highlight: Brans, K. I., Tüzün, N., Sentis, A., De Meester, L.,Stoks, R. (2021). Cryptic eco-evolutionary feedback in the city: Urban evolution of prey dampens the effect of urban evolution of the predator. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.13601. Despite the strength and ubiquity of urban stressors on multiple taxa, there have been minimal attempts to determine the ecological consequences of urban evolution on multiple species. BransTüzün et al. use a well-known predator prey system-damselfly nymphs Ischnura elegans and water fleas Daphnia magna-to test whether scenarios in which both species evolve in response to urbanization differ from scenarios in which only the predator or prey evolves. The authors show that urban damselflies showed higher encounter and predation rates when paired with rural prey, but that the advantages conferred by urbanization-driven adaptation disappeared when urban predators encountered urban prey. This represents a cryptic eco-evolutionary feedback, where evolution of both predator and prey concealed the effect of evolution in each partner individually. Results suggest that mismatches in the evolutionary responses of interacting species may have significant ecological consequences, and highlight the importance of a multi-species approach in eco-evolutionary dynamics research.

Periprosthetic joint infection (PJI) is a devastating complication of orthopedic implant surgeries, such as total knee and hip arthroplasties. Treatment requires additional surgeries because antibiotics have limited efficacy due to biofilm formation and resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA). A non-pharmaceutical approach is needed, and examples of this are found in nature; dragonfly and cicada wings are antibacterial because of their nanopillar surface structure rather than their chemistry. Carbon-infiltrated carbon nanotube (CICNT) surfaces exhibit a similar nanopillar structure, and have been shown to facilitate osseointegration, and it is postulated that they might provide a structurally-derived resistance to bacterial proliferation and biofilm formation. The objective of this study was to test the biofilm resistance of CICNT coatings. Two types of CICNT were produced: a vertically aligned CNT forest on a silicon substrate using a layer of iron as the catalyst (CICNT-Si) and a random-oriented CNT forest on stainless steel (SS) substrate using the substrate as the catalyst (CICNT-SS). These were tested against SS and carbon controls. After 48 h in an MRSA biofilm reactor, samples demonstrated that both types of CICNT coatings significantly (p

BACKGROUND Dragonfly and damselfly larvae have been considered as possible biocontrol agents against young instars of mosquito vectors in urban environments. Yet our knowledge about adult odonate predation against mosquito adults is scarce. We quantified daily and annual predation rates, consumption rates and prey preferences of adult Hetaerina vulnerata male damselflies in an urban park. A focus on predation of mosquito species was provided, quantified their arbovirus (dengue, chikungunya and Zika) infection rates and biting activity. RESULTS Foraging times of H. vulnerata overlapped with those of the maximum activity of hematophagous mosquitoes. The most consumed preys were Diptera and Hymenoptera and, in lower quantities, Hemiptera, Coleoptera, Trichoptera, Psocoptera and Neuroptera. Of note, 7% of the diet was represented by hematophagous dipterans, with 2.4% being Aedes aegypti and Aedes albopictus. Prey abundance in the diet coincided with that of the same species in the environment. The arboviral infection rate (dengue, chikungunya and Zika) was 1.6% for A. aegypti and A. albopictus. The total biting rate of these mosquito vectors was 16 bites per person per day, while the annual rate of infectious bites was 93.4. CONCLUSION Although 2.4% for both Aedes species seems a low consumption, considering the presence of 12 odonate species at the park, it can be argued that adult odonates may play a relevant role as mosquito vector regulators, therefore impacting the spread of mosquito-borne diseases. Our study outlines the need for further research on the topic of the possible role of adult odonates for mosquito biocontrol. © 2021 Society of Chemical Industry.

Recent climate change is altering the timing, duration and volume of river and stream flows globally, and in many regions, perennially flowing rivers and streams are drying and switching to intermittent flows. Profound impacts on aquatic biota are becoming apparent, due in part to the strong influence of flow regime on the evolution of life history. We made predictions of life-history responses for 13 common aquatic invertebrate species (four caddisflies, five mayflies, two stoneflies, a dragonfly and an amphipod), to recent flow regime change in Australian mediterranean climate streams, based on historic studies in the same streams. Size distributions, phenology, voltinism and synchrony were compared, revealing five main responses. More than half of the species were restricted to perennially flowing streams and were absent from those that had switched to intermittent flows (including all four caddisfly species). These formerly common species are at risk of extinction as climate change progresses. Two mayfly species had divergent responses in voltinism and synchrony, and one relied on drought micro-refuges to persist. One stonefly species changed development timing to suit the new flow regime, and the amphipod species retreated to subterranean refuges. Two formerly common species were not detected at all during 2016-2017. In addition, a new mayfly species and a caddisfly species proliferated under new flow regimes, because they had life histories suited to brief hydroperiods. Importantly, previous life history rarely predicted species' actual responses to climate-driven flow regime change, raising doubts about the veracity of predictions based on species traits. This is because a species' potential for flexible phenology or growth rate is not necessarily indicated by life-history traits.

Aim The aim was to understand the representativeness and accuracy of expert range maps and to explore alternative methods for mapping species distributions accurately. Location Global. Time period Contemporary. Major taxa studied Terrestrial vertebrates and Odonata. Methods We analysed the biases in 50,768 animal International Union for Conservation of Nature, Global Assessment of Reptile Distributions and BirdLife species maps and assessed the links between these maps and existing political boundaries and various non-ecological boundaries to assess their accuracy for certain types of analyses. We cross-referenced each species map with data from the Global Biodiversity Information Facility to assess whether maps captured the whole range of a species and what percentage of occurrence points fell within the assessed range of the species. In addition, we used a number of different methods to map diversity patterns and compared these with high-resolution models of distribution patterns. Results On average, 20-30% of the non-coastal range boundaries of species overlapped with administrative national boundaries. In total, 60% of areas with the highest spatial turnover in species (high densities of species range boundaries marking high levels of shift in the community of species present) occurred at political boundaries, which was especially common in Southeast Asia. Different biases existed for different taxa, with gridded analysis in reptiles, river basins in Odonata (except the Americas) and county boundaries for amphibians in the USA. On average, up to half (25-46%) of the recorded range points of species fell outside their mapped distributions. Filtered minimum convex polygons performed better than expert range maps in reproducing modelled diversity patterns. Main conclusions Expert range maps showed high bias at administrative borders in all taxa, but this was highest at the transition from tropical to subtropical regions. The methods used were inconsistent across space, time and taxa, and the ranges mapped did not match species distribution data. Alternative approaches can reconstruct patterns of distribution better than expert maps, and data-driven approaches are needed to provide reliable alternatives to gain a better understanding of species distributions.

Structural complexity of habitats modifies trophic interactions by providing refuges and altering predator and prey behaviour. Nonlinear effects on trophic interaction strengths driven by these mechanisms may alter food web dynamics and community structure in response to habitat modifications. However, changes in functional response, the relationship between prey density and feeding rate, along habitat complexity (HC) gradients are little understood. We quantified functional responses along a HC gradient from an entirely unstructured to highly structured habitat in a freshwater system, using dragonfly larvae (Aeshna cyanea) preying on Chaoborus obscuripes larvae. To disentangle mechanisms by which changes in HC affect functional responses, we used two different approaches-a population-level and a behavioural experiment-applied an information theoretic approach to identify plausible links between HC and functional response parameters, and compared our results to previous studies. Functional response shape did not change, but we found strong evidence for nonlinear dependence of attack rate and handling time on HC in our study. Combined results from both experiments imply that attack rate increased stepwise between the unstructured and structured habitats in line with the threshold hypothesis, because the predators gained better access to the prey. Handling time was lowest at an intermediate HC level in the population-level experiment while the direct estimate of handling time did not vary with HC in the behavioural experiment. These differences point towards HC-driven changes in foraging activity and other predator and prey behaviour. Most previous studies reported stepwise decrease in attack rate in line with the threshold hypothesis or no change with increasing HC. Moreover, changes in the handling time parameter with HC appear to be relatively common but not conforming to the threshold hypothesis. Overall, increased HC appears to, respectively, weaken and strengthen trophic links in 2D and 3D predator-prey interactions. We conclude that detailed understanding of HC effects on food webs requires complementary experimental approaches across HC gradients that consider predator foraging strategies and predator and prey behaviour. Such studies can also help guide conservation efforts as addition of structural elements is frequently used for restoration of degraded aquatic habitats.

Genetic and morphological identification of dragonflies' larvae species in three high-elevation Andean tropical lakes was done using DNA barcoding of the cytochrome oxidase 1 gene (COI). Phylogeny allowed inferring the evolutionary relationships of at least five species (from 74 samples) that belong to two different families within the Odonata order.

Motivation Freshwater insects comprise 60% of freshwater animal diversity; they are widely used to assess water quality, and they provide prey for numerous freshwater and terrestrial taxa. Our knowledge of the distribution of freshwater insect diversity in the USA is incomplete because we lack comprehensive, standardized data on their distributions and functional traits at the scale of the contiguous United States (CONUS). We fill this knowledge gap by presenting Freshwater insects CONUS: A database of freshwater insect occurrences and traits for the contiguous United States. This database includes 2.05 million occurrence records for 932 genera in the major freshwater insect orders, at 51,044 stream locations sampled between 2001 and 2018 by federal and state biological monitoring programmes. Compared with existing open-access databases, we tripled the number of occurrence records and locations and added records for 118 genera. We also present life-history, dispersal, morphological and ecological traits and trait affinities (analogous to fuzzy-coded traits) for 1,007 stream insect genera, assembled from existing databases, reference books and the primary literature. We nearly doubled the number of traits for 11 trait groups and added traits for 180 genera that were not available from open-access databases. Our database, Freshwater insects CONUS, facilitates the mapping of freshwater insect taxonomic and functional diversity and, when paired with environmental data, will provide a powerful resource for quantifying how the environment shapes stream insect diversity and taxon-specific distributions. Main types of variables contained Georeferenced occurrence records and traits for stream insects. Spatial location and grain Contiguous United States at a grain of c. 1 m2. Time period and grain Occurrence records from January 2001 to December 2018, with 1-day temporal resolution. Traits from January 1911 to December 2018. Major taxa and level of measurement Genera from the orders Coleoptera, Diptera, Ephemeroptera, Hemiptera, Lepidoptera, Megaloptera, Neuroptera, Odonata, Plecoptera and Trichoptera. Software format .csv.

Freshwater habitats are among the most threatened and least studied habitats in arid regions of Iran. Discovering factors responsible for the spatial variation of biodiversity are one of the main considerations in conservation biology. As a first step towards developing conservation strategies, we aimed to investigate the beta diversity and response of Odonata assemblages to climate and landscape variables in arid and semi‐arid regions of Iran. A total of 120 water bodies were surveyed. The beta diversity distance matrices were calculated for Odonata, Anisoptera, and Zygoptera, using the Jaccard dissimilarity coefficient. Also, the replacement and richness difference components of Odonata beta diversity were computed. Each of the five dissimilarity matrices was modelled by generalised dissimilarity modelling (GDM). We recorded 58 species of Odonata that represent 58% of the Odonata species in Iran. The average total beta diversity was high (0.873). GDMs results showed that the most influential variables varied between the replacement and richness difference components of Odonata beta diversity as well as between the two Odonata suborders. Anisoptera were most strongly affected by the temperature annual range, while the most important variable for Zygoptera was the average wind speed in April. Our results suggest that the studies of the drivers of biodiversity patterns benefit from beta diversity partitioning also from comparing species groups with different ecological preferences. The high biodiversity of the studied water bodies as well as the anthropogenic and climate threats that they are faced with, make these ecosystems a conservation priority.

Predation is a key ecological interaction affecting populations and communities. Climate warming can modify this interaction both directly by the kinetic effects of temperature on biological rates and indirectly through integrated behavioural and physiological responses of the predators and prey. Temperature dependence of predation rates can further be altered by predator-induced plasticity of prey locomotor activity, but empirical data about this effect are lacking. We propose a general framework to understand the influence of predator-induced developmental plasticity on behavioural thermal reaction norms in prey and their consequences for predator-prey dynamics. Using a mesocosm experiment with dragonfly larvae (predator) and newt larvae (prey), we tested if the predator-induced plasticity alters the elevation or the slope of the thermal reaction norms for locomotor activity metrics in prey. We also estimated the joint predator-prey thermal response in mean locomotor speed, which determines prey encounter rate, and modelled the effect of both phenomena on predator-prey population dynamics. Thermal reaction norms for locomotor activity in prey were affected by predation risk cues but with minor influence on the joint predator-prey behavioural response. We found that predation risk cues significantly decreased the intercept of thermal reaction norm for total activity rate (i.e. all body movements) but not the other locomotor activity metrics in the prey, and that prey locomotor activity rate and locomotor speed increased with prey density. Temperature had opposite effects on the mean relative speed of predator and prey as individual speed increased with temperature in predators but decreased in prey. This led to a negligible effect of body temperature on predicted prey encounter rates and predator-prey dynamics. The behavioural component of predator-prey interaction varied much more between individuals than with temperature and the presence of predation risk cues in our system. We conclude that within-population variation in locomotor activity can buffer the influence of body temperature and predation risk cues on predator-prey interactions, and further research should focus on the magnitude and sources of behavioural variation in interacting species to predict the impact of climate change on predator-prey interactions and food web dynamics.

Global warming is causing plastic and evolutionary changes in the phenotypes of ectotherms. Yet, we have limited knowledge on how the interplay between plasticity and evolution shapes thermal responses and underlying gene expression patterns. We assessed thermal reaction norm patterns across the transcriptome and identified associated molecular pathways in northern and southern populations of the damselfly Ischnura elegans. Larvae were reared in a common garden experiment at the mean summer water temperatures experienced at the northern (20°C) and southern (24°C) latitudes. This allowed a space-for-time substitution where the current gene expression levels at 24°C in southern larvae are a proxy for the expected responses of northern larvae under gradual thermal evolution to the predicted 4°C warming. Most differentially expressed genes showed fixed differences across temperatures between latitudes, suggesting that thermal genetic adaptation will mainly evolve through changes in constitutive gene expression. Northern populations also frequently showed plastic responses in gene expression to mild warming, while southern populations were much less responsive to temperature. Thermal responsive genes in northern populations showed to a large extent a pattern of genetic compensation, namely gene expression that was induced at 24°C in northern populations remained at a lower constant level in southern populations, and were associated with metabolic and translation pathways. There was instead little evidence for genetic assimilation of an initial plastic response to mild warming. Our data therefore suggest that genetic compensation rather than genetic assimilation may drive the evolution of plasticity in response to mild warming in this damselfly species. ispartof: MOLECULAR ECOLOGY vol:29 issue:24 pages:4823-4834 ispartof: location:England status: published

Previous macrophysiological studies suggested that temperature‐driven color lightness and body size variations strongly influence biogeographical patterns in ectotherms. However, these trait–environment relationships scale to local assemblages and the extent to which they can be modified by dispersal remains largely unexplored. We test whether the predictions of the thermal melanism hypothesis and the Bergmann's rule hold for local assemblages. We also assess whether these trait–environment relationships are more important for species adapted to less stable (lentic) habitats, due to their greater dispersal propensity compared to those adapted to stable (lotic) habitats.We quantified the color lightness and body volume of 99 European dragon‐ and damselflies (Odonata) and combined these trait information with survey data for 518 local assemblages across Europe. Based on this continent‐wide yet spatially explicit dataset, we tested for effects temperature and precipitation on the color lightness and body volume of local assemblages and assessed differences in their relative importance and strength between lentic and lotic assemblages, while accounting for spatial and phylogenetic autocorrelation.The color lightness of assemblages of odonates increased, and body size decreased with increasing temperature. Trait–environment relationships in the average and phylogenetic predicted component were equally important for assemblages of both habitat types but were stronger in lentic assemblages when accounting for phylogenetic autocorrelation.Our results show that the mechanism underlying color lightness and body size variations scale to local assemblages, indicating their general importance. These mechanisms were of equal evolutionary significance for lentic and lotic species, but higher dispersal ability seems to enable lentic species to cope better with historical climatic changes. The documented differences between lentic and lotic assemblages also highlight the importance of integrating interactions of thermal adaptations with proxies of the dispersal ability of species into trait‐based models, for improving our understanding of climate‐driven biological responses., We quantified the color lightness and body volume of 99 European dragon‐ and damselflies (Odonata) and combined this trait information with survey data for 518 local assemblages across Europe to test whether trait‐environment relationships previously reported at coarse spatial scales also hold for spatially explicit local assemblages. We show that the color lightness of odonates assemblages increased and body size decrease with increasing temperature across Europe, supporting the thermal melanism hypothesis and Bergmann's rule, respectively. Accounting for differences in the dispersal/recolonization ability between lentic and lotic species and the phylogenetic relationships of species indicated that both groups show similar trait‐environment relationships in the phylogenetically predicted part of traits (evolutionary responses), but differ in their responses to (recent) historical climatic changes.

Pleiotropy (multiple phenotypic effects of single genes) and epistasis (gene interaction) have key roles in the development of complex phenotypes, especially in polymorphic taxa. The development of discrete and heritable phenotypic polymorphisms often emerges from major-effect genes that interact with other loci and have pleiotropic effects on multiple traits. We quantified gene expression changes during ontogenetic color development in a polymorphic insect (damselfly: Ischnura elegans), with three heritable female morphs, one being a male mimic. This female color polymorphism is maintained by male mating harassment and sexual conflict. Using transcriptome sequencing and de novo assembly, we demonstrate that all three morphs downregulate gene expression during early color development. The morphs become increasingly differentiated during sexual maturation and when developing adult coloration. These different ontogenetic trajectories arise because the male-mimic shows accelerated (heterochronic) development, compared to the other female morphs. Many loci with regulatory functions in reproductive development are differentially regulated in the male-mimic, including upstream and downstream regulators of ecdysone signaling and transcription factors potentially influencing sexual differentiation. Our results suggest that long-term sexual conflict does not only maintain this polymorphism, but has also modulated the evolution of gene expression profiles during color development of these sympatric female morphs.

Species typically align along a fast-slow life-history continuum, yet it is not clear to what extent oxidative stress physiology can be integrated with this continuum to form a 'pace-of-life syndrome', especially so in invertebrates. This is important, given the assumed role of oxidative stress in mediating life-history trade-offs, and the prediction that species with a faster pace should be more vulnerable to oxidative stress. We tested whether a species' life-history pace, here represented by its growth rate, can predict species-level differentiation in physiology and sensitivity to oxidative stress. Therefore, we exposed four species of Ischnura damselflies that strongly align along a fast-slow life-history continuum to different levels of ultraviolet (UV) radiation. We measured an extended set of physiological traits linked to the pace-of-life: standard metabolic rate, oxidative stress physiology (antioxidant enzymes and oxidative damage) and defence/condition traits (investment in immune function, energy storage and structural defence). Despite strong species differences in growth rate and physiology, growth rate did not predict species-level differentiation in physiology. Hence there was no support for the integration of metabolic rate, oxidative stress physiology or defence/condition traits into a species-level syndrome. Ultraviolet exposure affected nearly all traits: it reduced growth rate and increased metabolic rate, affected all oxidative stress physiology traits and increased the two defence traits (immune function, and melanin content). Nevertheless, the pace-of-life based on growth rate did not predict sensitivity to UV. Instead, the observed pattern of investment in structural UV defence (melanin) might have reduced the need for enzymatic antioxidant defence, this way potentially decoupling the covariation between the life-history pace and oxidative stress physiology. The absence of an integrated axis of life-history and physiological variation indicates no major constraints for the evolution of these traits among the studied damselfly species. Our study highlights that ecological differences between species may decouple covariation between species' life-history pace and their physiology, as well as their sensitivity to environmental stressors. ispartof: Journal Of Animal Ecology vol:89 issue:7 pages:1711-1721 ispartof: location:England status: accepted

Predators have a key role shaping competitor dynamics in food webs. Perhaps the most obvious way this occurs is when predators reduce competitor densities. However, consumption could also generate phenotypic selection on prey that determines the strength of competition, thus coupling consumptive and trait-based effects of predators. In a mesocosm experiment simulating fish predation on damselflies, we found that selection against high damselfly activity rates - a phenotype mediating predation and competition - weakened the strength of density dependence in damselfly growth rates. A field experiment corroborated this finding and showed that increasing damselfly densities in lakes with high fish densities had limited effects on damselfly growth rates but generated a precipitous growth rate decline where fish densities were lower - a pattern expected because of spatial variation in selection imposed by predation. These results suggest that accounting for both consumption and selection is necessary to determine how predators regulate prey competitive interactions.

Most research on eco-evolutionary feedbacks focuses on ecological consequences of evolution in a single species. This ignores the fact that evolution in response to a shared environmental factor in multiple species involved in interactions could alter the net cumulative effect of evolution on ecology. We empirically tested whether urbanization-driven evolution in a predator (nymphs of the damselfly Ischnura elegans) and its prey (the water flea Daphnia magna) jointly shape the outcome of predation under simulated heatwaves. Both interactors show genetic trait adaptation to urbanization, particularly to higher temperatures. We cross-exposed common-garden reared damselflies and Daphnia from replicated urban and rural populations, and quantified predation rates and functional response traits. Urban damselfly nymphs showed higher encounter and predation rates than rural damselflies when exposed to rural prey, but this difference disappeared when they preyed on urban Daphnia. This represents a case of a cryptic evo-to-eco feedback, where the evolution of one species dampens the effects of the evolution of another species on their interaction strength. The effects of evolution of each single species were strong: the scenario in which only the predator or prey was adapted to urbanization resulted in a c. 250% increase in encounter rate and a c. 25% increase in predation rate, compared to the rural predator-rural prey combination. Our results provide unique evidence for eco-evolutionary feedbacks in cities, and underscore the importance of a multi-species approach in eco-evolutionary dynamics research.Onderzoek naar eco-evolutionaire terugkoppelingen focust vaak op de ecologische gevolgen van evolutie in één soort. Bijgevolg negeert men de mogelijkheid dat evolutionaire veranderingen van meerdere interagerende soorten als respons op een gedeelde omgevingsverandering met elkaar kunnen interfereren en zo het netto effect van evolutie op ecologische processen kan veranderen. We testten empirisch of door verstedelijking gedreven evolutie in een predator (larven van de waterjuffer Ischnura elegans) en zijn prooi (de watervlo Daphnia magna) de uitkomst van predatie onder gesimuleerde hittegolven beïnvloedt. Beide interactoren vertonen genetische adaptatie aan de stadsomgeving, meer specifiek de daar voorkomende hogere temperaturen. We stelden waterjuffers en watervlooien, afkomstig van gerepliceerde stedelijke en rurale populaties en opgegroeid in een gestandaardiseerde laboratoriumomgeving, bloot aan elkaar volgens een experimenteel design waarbij alle combinaties van herkomst van prooi en predator werden getest. We kwantificeerden telkens de predatiesnelheid en functionele respons-kenmerken. Stedelijke waterjufferlarven vertoonden een hogere ontmoetings- en predatiesnelheid dan larven afkomstig uit rurale gebieden wanneer ze blootgesteld werden aan rurale Daphnia, maar niet wanneer ze blootgesteld werden aan Daphnia afkomstig uit de stad. Deze bevinding wijst op een cryptische evo-naar-eco terugkoppeling, waarbij evolutie in één van de soorten het effect van evolutie van de andere soort op de sterkte van hun interactie dempt. De effecten van evolutie in elke soort apart waren sterk: de scenario's waarin enkel de predator of de prooi aangepast was aan de stadsomgeving resulteerde in een c. 250% stijging van de ontmoetingssnelheid en een c. 25% verhoging van de predatiesnelheid, in vergelijking met een situatie waarbij een rurale predator met een rurale prooi was gecombineerd. Deze resultaten leveren uniek bewijs voor een eco-evolutionaire terugkoppeling in steden en onderlijnen het belang van een multi-soorten benadering in het onderzoek naar eco-evolutionaire dynamieken.

Interspecific interactions, such as competition, are among the key factors that determine the distribution, abundance and diversity of organisms in natural communities of aquatic ecosystems. However, a marked reduction in the environmental integrity of streams may lead to modifications of the natural dynamics of these communities, including co-occurrence patterns and body size. In the Amazon, the replacement of forests by production systems is one of the leading causes of alterations to riverine ecosystem. The insects of the order Odonata (dragonflies and damselflies) are predators known to compete for environmental resources but are also sensitive to environmental changes such as those caused by shifts in land use. In this scenario, the present study evaluated species co-occurrence and body size patterns in adult odonates found at preserved and altered Amazonian streams, to determine whether there are morphological differences among the species that enable their coexistence. During the study, 98 streams in the eastern Amazon region were sampled, and a habitat integrity index (HII) was used to evaluate the integrity of each stream (based on variables such as the condition of the riparian vegetation and channel, and land use). Ten male individuals were selected from each species, and nine morphometric measurements were taken from each individual. A total of 3588 specimens were collected and distributed in nine families, 49 genera and 134 species. We found a non-random pattern of co-occurrence in the species of the odonate suborder Zygoptera and a random pattern in the suborder Anisoptera, in both preserved and altered streams. We found morphological divergence between pairs of zygopteran species, in the whole sample and both categories of stream integrity separately. No such morphological divergence was found in the pairs of anisopteran species. The distribution patterns of odonate species are limited by specific environmental processes, especially in preserved environments and in specialists, such as most zygopterans. Zygopteran species have more specific microhabitat requirements, which could explain this pattern, whereas anisopterans prefer open environments, which usually have a greater supply of resources, although there tends to be less microhabitat heterogeneity, which leads to reduced competition. Given this, future studies should use limiting similarity (e.g. morphological attributes) in addition to environmental and spatial factors to better understand the factors structuring these communities. Among these mechanisms, the effects of common ancestry (phylogenetic inertia) and biogeography are important factors that should also be considered in future studies. National Council for Scientific and Technological Development (Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ); UFPA/MPEG Graduate Program in Zoology; National Institute of Science and Technology, Biodiversity and Land Use in the Amazon (Instituto Nacional de Ciencia e Tecnologia Biodiversidade e Uso da Terra na Amazonia) [CNPq 574008/2008-0]; Brazilian Agricultural Research Corporation (Empresa Brasileira de Pesquisa Agropecuaria - Embrapa) [SEG: 02.08.06.005.00]; Darwin Initiative of the Government of the United Kingdom [17-023]; Natural Environment Research Council (NERC)UK Research & Innovation (UKRI)Natural Environment Research Council (NERC) [NE/F01614X/1, NE/G000816/1]; CNPqConselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) [304710/2019-9]; CoordenacAo de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), through PROCAD-AMAZONIA/CAPESCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) [88881.474457/2020-01]; FundacAo para a Ciencia e a Tecnologia (FCT) - Foundation for Science and Technology [UID/Multi/04326/2019]; Pro-Reitoria de Pesquisa e Pos-GraduacAo (PROPESP)/Universidade Federal do Para (UFPA) info:eu-repo/semantics/publishedVersion

Shifts in the fundamental and realised niche of individuals during their ontogeny are ubiquitous in nature, but we know little about what aspects of the niche change and how these changes vary across species within communities. However, this knowledge is essential to predict the dynamics of populations and communities and how they respond to environmental change. Here I introduce a range of metrics to describe different aspects of shifts in the realised trophic niche of individuals based on stable isotopes. Applying this multi‐variate approach to 2,272 individuals from 13 taxonomic and functional distinct species (Amphibia, Hemiptera, Coleoptera, Odonata) sampled in natural pond communities allowed me to: (1) describe and quantify the diversity of trophic niche shift patterns over ontogeny in multi‐dimensional space, and (2) identify what aspects of ontogenetic shifts vary across taxa, and functional groups. Results revealed that species can differ substantially in which aspects of the trophic niche change and how they change over ontogeny. Interestingly, patterns of ontogenetic niche shifts grouped in distinct taxonomic clusters in multi‐variate space, including two distinct groups of predators (Hemiptera versus Odonata). Given the differences in traits (especially feeding mode) across groups, this suggests that differences in ontogenetic niche shifts across species could at least partially be explained by variation in traits and functional roles of species. These results emphasise the importance of a multivariate approach to capture the large diversity of trophic niche shifts patterns possible in natural communities and suggest that differences in ontogenetic niche shifts follow general patterns.

1. Inducible defences are ubiquitous in the animal kingdom, but little is known about facultative changes in chemical defences in response to predators, especially so in vertebrates. 2. We tested for predator-induced changes in toxin production of larval common toads (Bufo bufo), which are known to synthesize bufadienolide compounds. 3. The experiment included larvae originating from three permanent and three temporary ponds reared in the presence or absence of chemical cues of three predators: dragonfly larvae, newts or fish. 4. Tadpoles raised with chemical cues of predation risk produced higher numbers of bufadienolide compounds and larger total bufadienolide quantities than predator-naive conspecifics. Further, the increase in intensity of chemical defence was greatest in response to fish, weakest to newts and intermediate to dragonfly larvae. Tadpoles originating from temporary and permanent ponds did not differ in their baseline toxin content or in the magnitude of their induced chemical responses. 5. These results provide the first compelling evidence for predator-induced changes in chemical defence of a vertebrate that may have evolved to enhance survival under predation risk.

Theory predicts that within-population differences in the pace-of-life can lead to cohort splitting and produce marked intraspecific variation in body size. Although many studies showed that body size is positively correlated with fitness, many argue that selection for the larger body is counterbalanced by opposing physiological and ecological selective mechanisms that favour smaller body. When a population split into cohorts with different paces of life (slow or fast cohort), one would expect to detect the fitness-size relationship among and within cohorts, that is, (a) slower-developing cohort has larger body size and higher fitness than faster-developing cohort, and (b) larger individuals within each cohort show higher fitness than smaller individuals. Here, we test these hypotheses in capture-mark-recapture field surveys that assess body size, lifespan, survival and lifetime mating success in two consecutive generations of a partially bivoltine aquatic insect, Coenagrion mercuriale, where the spring cohort is slower-developing than the autumn cohort. As expected, body size was larger in the slow-developing cohort, which is consistent with the temperature-size rule and also with the duration of development. Body size seasonal variation was greater in slow-developing cohort most likely because of the higher variation in age at maturity. Concordant with theory, survival probability, lifespan and lifetime mating success were higher in the slow-developing cohort. Moreover, individual body size was positively correlated with survival and mating success in both cohorts. Our study confirms the fitness costs of fast pace-of-life and the benefits of larger body size to adult fitness.

A shift in the relative arrival of offspring, for example a shift in hatching time, can affect competition at the intraspecific level through size-mediated priority effects, where the larger individuals gain more resources. These priority effects are likely to be affected by climate warming and the rate of intraspecific predation, that is cannibalism. In a laboratory experiment, we examined size-mediated priority effects in larvae of the univoltine damselfly, Lestes sponsa, at two different temperatures (21 and 23°C). We created three size groups of larvae by manipulating hatching time: early hatched with a large size (extra-advanced), intermediate hatched with an intermediate size (advanced) and late hatched with a small size (non-advanced). Thereafter, we reared the larvae from these groups in non-mixed and mixed groups of 12 larvae. We found strong priority and temperature effects. First, extra-advanced larvae most often had higher survival, growth and development rates than non-advanced larvae in mixed groups, compared to groups that consisted of only extra-advanced larvae. Second, temperature increased growth and development rates and cannibalism. However, the strength of priority effects did not differ between the two experimental temperatures, because there was no statistical interaction between temperature and treatments. That is, the mixed and non-mixed groups of non-advanced, advanced and extra-advanced larvae showed the same relative change in life-history traits across the two temperatures. Non-advanced and advanced larvae had similar or higher growth rate and mass in mixed groups compared to non-mixed groups, suggesting that predation from advanced larvae in the mixed group released resources for the non-advanced and advanced larvae that survived despite cannibalism risk. Thus, a thinning effect occurred due to cannibalism caused by priority effects. The results suggest that a shift in the relative arrival of offspring can cause temperature-dependent priority effects, mediated through cannibalism, growth and development, which may change the size distribution and abundance of emerging aquatic insects.