Search

Because insects are unable to regulate their body temperatures, they are vulnerable to rising temperatures and habitat disturbances that limit access to optimal microhabitats. This study examines how these factors affect the taxonomic and functional diversity of Odonata insects (Anisoptera and Zygoptera) in a tropical dry landscape. We assessed taxonomic diversity using Hill numbers (0D, 1D, 2D) and functional diversity in preserved and disturbed sites within a tropical dry forest. Functional diversity was measured using the standardised effect size (SES) of functional richness, evenness, divergence and community‐weighted means (CWMs), focusing on traits related to heat tolerance and resource acquisition (body colouration and size). Taxonomic diversity was positively related to high temperatures and vegetation in Anisoptera, with no relation for Zygoptera. The SES of functional richness for Zygoptera was higher in preserved areas, while anisopterans showed no changes. Only Anisoptera showed a negative correlation between functional evenness and maximum temperatures. Functional divergence in both suborders was higher in disturbed areas. In Anisoptera, the CWM of body colour lightness was higher in disturbed sites, but neither environmental factor affected the CWM of body size in either suborder. While disturbance limited trait variability in zygopterans, it favoured species with extreme traits in both suborders. Reduced trait variability in preserved sites may have affected adaptability to future disturbances. Our study highlights that Odonata communities maintain stable taxonomic diversity despite disturbances, but shifts in functional diversity could compromise their resilience and ecological roles. [ABSTRACT FROM AUTHOR]

ABSTRACT Biodiversity monitoring increasingly relies on molecular methods such as eDNA metabarcoding. However, sound applications have so far been only established for a limited number of taxonomic groups. More information on the strengths and weaknesses of eDNA methods, especially for poorly covered groups, is essential for practical applications to achieve the highest possible reliability. We compared amphibian and Odonata data from eDNA metabarcoding and traditional transect walks on N = 56 plots in 38 water bodies distributed over six extraction sites for building materials in Northwest Germany. The traditional amphibian assessment included visual encounters, dip netting and acoustic detection, while Odonata were assessed through exuviae. In total, both methods detected 8 out of 11 amphibian species, while the remaining three species were detected by eDNA only. We did not find differences in amphibian species numbers per plot, but mean detection probabilities were higher with metabarcoding. In contrast, both methods detected 10 out of 29 Odonata species, while the remaining 19 species were detected by exuviae only. Species numbers per plot were higher for exuviae and only 30% of species were detected with metabarcoding. The species identified by eDNA were those with high abundance, and their detection probabilities were similar to transect walks. The results for amphibians show equal suitability and high complementarity of the compared methods. Metabarcoding detected species more efficiently and therefore offers a suitable protocol for biodiversity monitoring. For Odonata, eDNA metabarcoding showed considerable gaps, implying the need for protocol evaluation and improvement in assessment of ecological communities based on eDNA. [ABSTRACT FROM AUTHOR]

Mating between species occurs within many insect orders. The result of heterospecific mating depends upon the effectiveness of pre‐ and post‐reproductive barriers. Incomplete reproductive barriers lead to introgression of DNA into one species or both. Intricate genital morphology among dragonflies provides little assurance of species specificity given that heterospecific mating or mating attempts have been observed among many species. The genetic consequence is unknown for many heterospecific matings. For example, Somatochlora species mating and genetic exchange have been hypothesized based on observational records and individuals with hybrid morphology. We investigate the potential of heterospecific mating between North American Somatochlora species as inferred from multi‐gene phylogenies. We used mitochondrial genes (COI and ND3) and nuclear genes (EF1‐α and ITS2) to construct phylogenies using maximum parsimony. Observation of non‐monophyletic mtDNA lineages but monophyletic nDNA lineages between Somatochlora sister‐species would indicate mtDNA introgression and suggest heterospecific matings. Our results highlighted three instances of non‐monophyly of mtDNA clades in the following groups: (i) S. hineana + S. tenebrosa; (ii) S. kennedyi + S. forcipata + S. franklini; and (iii) S. calverti + S. provocans + S. filosa. Analysis of partitioned Bremer support indicates that mtDNA COI largely contributed to the non‐monophyly of these species, thus suggesting mtDNA introgression resulting from heterospecific matings. Additionally, the topology resulting from the combined data analysis was concordant with previous taxonomic understanding of Somatochlora species groups. These multi‐gene phylogenies of North American Somatochlora are the first, providing a foundation for future ecological and evolution studies and knowledge for effective decision‐making and public policy, which is especially important for the endangered species, S. hineana. [ABSTRACT FROM AUTHOR]

Aim: Human activities pose many challenges to freshwater biodiversity. Among these, is landscape transformation, such as conversion of natural grassland to plantation forestry, impacting both terrestrial and freshwater biodiversity. Functional diversity measures provide substantial information on current and emerging impacts on biological communities, and aid conservation decisions relative to anthropogenic impacts. We determined (1) environmental similarities among 10 freshwater biotope types; (2) whether freshwater biotopes in conservation corridor networks support equal levels of functional richness and divergence compared with an extensive neighbouring protected area; (3) whether certain biotopes are more important for maintaining functional richness and divergence than others; and (4) whether associations between traits and biotope types could be identified. Location: The northeastern coastal region of South Africa. Methods: Using dragonflies as model organisms, and data from 140 freshwater lotic and lentic sites, we investigated the distribution of dragonfly traits across a plantation forestry‐natural grassland landscape mosaic with a range of biotope types. Results: Lake sites were different in their environmental conditions compared with the other biotopes. Environmental conditions were variable among the other biotope types and were difficult to distinguish. Freshwater biotopes in the conservation corridors supported equal levels of functional richness and divergence compared with those in the protected area. Overall, dragonfly functional richness and divergence were low at lake sites and wallows, while all other biotopes supported high levels of functional richness and divergence. Trait associations were complex across the waterscape and driven by habitat selection, flight behaviour and ecological sensitivity. Main Conclusions: Maintaining a mosaic of small lentic and lotic habitats would best support dragonfly conservation in this transformed landscape. A combination of biotopes offers a wide range of environmental conditions essential for conserving the full range of dragonfly traits and species across the region. [ABSTRACT FROM AUTHOR]

Aim: Species have different distribution patterns across the globe and among biogeographical regions. The Nearctic and Palaearctic regions share lineages because of their parallel biogeographic histories and ecological conditions. As the number of phylogenetic studies increases, there are more insights into past exchange events between these two regions and their effects on the current distribution of diversity. However, several groups have not been tested and an overall generalization is still missing. Here, we analyse the biogeographic history across multiple genera of odonates to elucidate a general process of species exchange, vicariance and species divergence between these two regions. Location: The Holarctic, including the entire Nearctic and the East and West Palaearctic. Taxon: 14 genera of Odonata (Insecta). Methods: We reconstructed a time‐calibrated phylogenetic tree for each genus to determine species relationships and divergence time using 3614 COI sequences of 259 species. Biogeographic ancestral range estimation was inferred for each phylogeny using BioGeoBEARS. Preferred habitat (lotic versus lentic) was established for each species. Results: Exchange events were not restricted in time, direction or either lentic habitat or lotic habitat. Most genera crossed between both regions only once, and it was mainly across the Beringia, while three diverse anisopteran genera revealed multiple exchanges. Recent exchanges during the Pleistocene were associated with cold‐dwelling and lentic species. Main Conclusions: Our finding reveals the absence of a generalizable pattern of species exchange and divergence between the Nearctic and Palaearctic regions; instead, we found lineage‐specific biogeographic patterns. This finding highlights the complexity of drivers and functional traits that shaped current diversity patterns. Moreover, it emphasizes that general conclusions cannot be formulated based on one single clade. [ABSTRACT FROM AUTHOR]

Aquatic insects are key to wetland ecological functioning, and the distribution of amphibious insects such as Odonata jointly depends on environmental conditions in the aquatic and terrestrial settings. Therefore, untangling the relative effects of within‐wetland and landscape composition can help predict the responses of Odonata to environmental alterations in wetlands. Using data from 19 wetlands spanning over the southern Brazilian Pampa (center‐western Rio Grande do Sul state), we assessed the relative importance of water chemistry and land‐cover variables to the richness and composition of larval Odonata assemblages (and suborders Anisoptera and Zygoptera). Anisoptera richness decreased with pH and bare soil area. Water pH and areas of bare soil, mosaic of agricultural land use, and waterbodies land cover were the main drivers of Odonata and Zygoptera composition. Our results indicate that land cover is the main driver of the assemblage structure of larval Odonata, although a complex interplay of mechanisms associated with land conversion and water quality drive the distribution of larval Odonata in freshwater wetlands of the Brazilian Pampa. The major implication of our findings is that land cover modification is the major threat to Odonata distribution in Pampean wetlands, with potential impacts on the trophic structure and functioning of these ecosystems. [ABSTRACT FROM AUTHOR]

Applying BEAST v1.10.4, we constructed a Bayesian Inference tree comprising 322 taxa, primarily representing Paleoptera (Odonata and Ephemeroptera; Pterygota), Zygentoma and Archaeognatha (Apterygota; paraphyly), and Neoptera (Plecoptera; Pterygota), based on a 2685 bp sequence dataset. Our analyses revealed that robust dating required the incorporation of both Quaternary and pre‐Quaternary dates. To achieve this, our dating incorporated a 1.55 Ma (Quaternary) geological event (the formation of the Ryukyu Islands) and a set of chronologically well‐founded fossil dates, spanning from up to 400 Ma (Devonian) for the stem Archaeognatha, 320 Ma (Carboniferous) for the crown of Paleoptera, 300 Ma (Carboniferous) for the crown Ephemeroptera, and 280 Ma (Permian) for the crown Odonata, down to 1.76 Ma (Quaternary) for Calopteryx japonica, encompassing a total of 22 calibration points (events: 6, fossils: 16; Quaternary: 7, pre‐Quaternary: 15). The resulting dated tree aligns with previous research, albeit with some dates being overestimated. This overestimation was mainly due to the lack of Quaternary calibration and the exclusive dependence on pre‐Quaternary calibration, though the application of maximum age constraints also played a role. Our minimum age dating demonstrates that the molecular clock did not uniformly progress, rendering rate dating an inapplicable approach. We observed that the base substitution rate is time‐dependent, with an exponential increase evident from around 20 Ma (Miocene) to the present time, exceeding an order of magnitude. The extensive radiation and speciation of Insecta and Paleoptera, potentially resulting from the severe climatic changes associated with the Quaternary, including the commencement of glacial and interglacial cycles, may have significantly contributed to this increase in base substitution rates. Additionally, we identified a potential peak in base substitution rates during the Carboniferous period, around 320 million years ago, possibly corresponding to the Late Paleozoic Ice Age. [ABSTRACT FROM AUTHOR]

Riverine caves are special habitats that are home to many aquatic and terrestrial species. Some Odonata species and their emerging are recorded at the entrance and in the twilight zones of subterranean habitats around the world. However, the emergence of any Odonata species has not been recorded in the dark zones of caves or other subterranean habitats. We report the first evidence of the emerging of the Hyrcanian Goldenring, Cordulegaster vanbrinkae Lohmann, 1993, as an endemic species of the Hyrcanian biogeographical region, in the dark zone of Danial Cave, in the World Heritage‐listed Hyrcanian Forests, northern Iran. During 2020–2023, three newly emerged and three exuviae of the species were recorded in the entrance zone (25 m) and the dark zone of the cave (200–280 m). The main hypothesis of the study is the entry and exit of adults from the cave entrance. However, we still do not know if the newly emerged will leave the cave or not. We still need more study on the biology and ecology of the species inside and around the cave. Danial Cave, with its high biodiversity, is one of the most important caves in the Middle East, and is urgently in need of conservation as a national natural monument. [ABSTRACT FROM AUTHOR]

Pantala flavescens (Fabricius) is the most well‐known seasonal migratory insect. This research focused on the molecular response of P. flavescens migration in summer and fall. A total of 17,810 assembled unigenes were obtained and 624 differentially expressed genes (DEGs) were identified in summer migration compared to fall migration. A number of DEGs, including cpr49Ae, itm2b, chitinase, cpr11B, laccase2, nd5, vtg2 and so on, had previously been reported to be involved in cold‐ and high‐temperature resistance. Functional enrichment analysis showed three pathways 'that antibacterial humoral response, response to bacterial, and lipid transporter activity' were significantly enriched in summer migration while that six pathways 'structural constituent of cuticle, chitin binding, mitochondrion, propanoate metabolism, citrate cycle, hypertrophic cardiomyopathy' were significantly enriched in fall migration. These results will provide a valuable baseline for further understanding of the molecular mechanisms of insect adaptation to different climate migrations. [ABSTRACT FROM AUTHOR]

Aim: Insects are one of the least studied taxa, with most species lacking basic ecological and biogeographical information. This problem is particularly acute in the tropics, where low sampling effort hampers accurate estimates of species richness at scale and potentially confounds efforts to identify the drivers of biogeographical gradients. Here, we evaluate the quality of the data on the distribution and diversity of odonate species in the Neotropics, while also examining the influence of sampling completeness on climate–richness relationships using a comprehensive database of odonates. Location: The Neotropics. Taxon: Odonata. Methods: Using 56,535 records collected from 1970 to 2021, we assess whether climate–species richness models vary under different scenarios of survey completeness. Results: Our survey compilation revealed that most Neotropical diversity of Odonata likely remains unknown. Only 1% of the one‐degree cells covering the Neotropics held reliable information on odonate species richness, with particularly severe gaps in the Caribbean, Central America, northeastern Brazil and northern Chile. Temperature, precipitation and potential evapotranspiration exert consistent effects on Odonata richness across the entire Neotropics, regardless the level of survey completeness. Whereas seasonality‐related variables are less important predictors of species richness at the biogeographical scale. Main Conclusions: By highlighting areas where inventories are more reliable and identifying regions that require increased data collection efforts and mobilization, our assessment offers a roadmap for improving the reliability of odonate inventories in the Neotropics. Furthermore, our findings underscore the importance of accounting for varying levels of survey completeness in macroecological models to reveal robust climate–species richness relationships. Simultaneously, they highlight strong climatic predictors of species richness, irrespective of survey effort intensity. These predictors provide a solid foundation for modelling and predicting odonate species richness in the Neotropics. [ABSTRACT FROM AUTHOR]

Scaling in insect wings is a complex phenomenon that seems pivotal in maintaining wing functionality. In this study, the relationship between wing size and the size, location, and shape of wing cells in dragonflies and damselflies (Odonata) is investigated, aiming to address the question of how these factors are interconnected. To this end, WingGram, the recently developed computer‐vision‐based software, is used to extract the geometric features of wing cells of 389 dragonflies and damselfly wings from 197 species and 16 families. It has been found that the cell length of the wings does not depend on the wing size. Despite the wide variation in wing length (8.42 to 56.5 mm) and cell length (0.1 to 8.5 mm), over 80% of the cells had a length ranging from 0.5 to 1.5 mm, which was previously identified as the critical crack length of the membrane of locust wings. An isometric scaling of cells is also observed with maximum size in each wing, which increased as the size increased. Smaller cells tended to be more circular than larger cells. The results have implications for bio‐mimetics, inspiring new materials and designs for artificial wings with potential applications in aerospace engineering and robotics. [ABSTRACT FROM AUTHOR]

Scarcity of morphological data limits the potential of functional ecology approaches, which rely on traits to elucidate ecological processes. Dragonflies and damselflies (Odonata) are a frequently used ecological model for which, however, only limited morphological data is available. Here, it is presented a field sampling protocol to collect ecologically relevant yet largely unavailable morphological traits of Odonata. The protocol enables the straightforward collection of traits from living individuals directly in the field. Those traits include body mass, wing area and wing loading as well as thorax width, hindwing length and body length. Furthermore, the protocol allows for posterior wing morphometric analyses. The protocol proved to be robust and universally applicable based on testing on roughly half (76) of all European odonate species. The use of this protocol can increase our understanding of odonatan morphology at interspecific and intraspecific levels and assist in developing mechanistic understanding of their ecology. [ABSTRACT FROM AUTHOR]

Identifying how temperature and food resources affect interactions between species is important for understanding how climate change will shape community structure in the future. Here, we tested how temperature and resource density affect survival and growth in the larval stage of two coexisting odonates: the damselfly Lestes sponsa and the dragonfly Sympetrum vulgatum. We performed a laboratory experiment at two temperatures (21 and 24°C) with two resource densities. We estimated the timing of egg hatching of individual egg clutches and thereafter the larval growth rate‐, survival‐ and size‐mediated priority effects under interspecific conditions. Eggs of both species hatched slightly faster at 24°C, and S. vulgatum eggs started hatching approximately 1 day earlier than L. sponsa eggs. However, this earlier hatching did not result in a size‐mediated priority effect, that is, a higher predation on the later hatching L. sponsa. Nevertheless, L. sponsa larvae were significantly larger than S. vulgatum at hatching. Growth rate and survival were significantly higher: (1) at 24°C compared with 21°C, (2) at high compared with low‐resource density and (3) in L. sponsa compared with S. vulgatum. Several significant interaction effects between resource density and temperature and between temperature and species were found. At high temperature, L. sponsa had a higher growth rate than S. vulgatum, but no difference in growth rate between species was found at low temperature. Additionally, a high‐resource density resulted in a higher growth rate in both species, but only under high temperature. There was a negative relationship between growth rate and survival in both species, suggesting that the higher growth rate of larvae was to some degree driven by intraguild predation and/or cannibalism. Our results imply that resource levels interact with temperature to affect interactions between the species. [ABSTRACT FROM AUTHOR]

We aim to explore what processes dominate community assembly of dragonflies (Odonata: Anisoptera) and damselflies (Odonata: Zygoptera) by differentiating the environmental and geographical drivers behind compositional turnover of narrow‐ranged versus widespread species. In this way, we further aim to describe patterns of species incidence and compositional turnover to expand upon the body of knowledge related to understanding biodiversity patterns and processes.We explored species turnover of dragonflies and damselflies separately, using zeta diversity to measure compositional turnover among multiple assemblages.Narrow‐ranged and widespread species within each suborder showed similar drivers. Specifically, both narrow‐ranged and widespread dragonflies show rapid turnover with small shifts in annual mean temperature, temperature seasonality and annual precipitation, whereas for damselflies, the major driver for turnover is distance between sites followed by climatic variables. Our results therefore show that odonate turnover is largely driven by climate, although the limited dispersal capabilities of damselflies also influences community assembly.Climate change could cause major changes in composition of odonates, presenting a challenge for conservation planning in Africa as species assemblages that were previously conserved may no longer be protected if their ranges shift outside protected areas. For damselflies, adaptation is a major concern, and with their limited dispersal capabilities and climate sensitivity, they may not be able to migrate effectively in response to changing climate conditions. The underlying assembly processes do not differ considerably for narrow‐ranged and widespread species within each suborder, suggesting that conservation planning tailored to each suborder may be sufficient in Africa. [ABSTRACT FROM AUTHOR]

Anthropogenic activities highly threaten neotropical freshwater habitats. Aquatic insects are sensitive to environmental alterations and thus considered under great risk due to such pressures. However, large‐scale gaps regarding the knowledge of the distribution of aquatic insect species remain in the Neotropics, particularly in the South American temperate grasslands (Pampas), hindering the knowledge of hotspots of aquatic insect diversity and the prioritization of conservation areas destined to protect their populations.Here, we review the current knowledge regarding the geographical distribution of Odonata species and use ecological niche models to estimate the areas with the highest potential richness of Odonata species in the Pampas. We also calculate a sampling effort index and interpolate it with maps of protected areas to identify the spatial knowledge gaps regarding their conservation in the regionOur compilation of Odonata species records retrieved 237 species for the Pampa. However, Odonata species were recorded in less than 2% of the Pampa. Our findings indicated a higher potential diversity of Odonata in northeastern Argentina, southern Uruguay and southern Brazil. Interpolations of sampling effort index and protected areas showed that 95% of the area potentially rich in Odonata species fall outside protected areas.Our study highlights the shortfall regarding the knowledge of the distribution of Odonata diversity in non‐forest landscapes of the Neotropical region. It also shows that protected areas of the Pampa cover a minor area of the Odonata species range in the region. [ABSTRACT FROM AUTHOR]

Dragonflies and damselflies are excellent bioindicators of the quality of both aquatic and terrestrial ecosystems. In our study, we assessed the usefulness of metric and meristic morphological traits as environmentally friendly and cost‐effective indicators of the integrative ecological quality of watercourses. Our study species of choice was the damselfly banded demoiselle, Calopteryx splendens (Harris) (Odonata: Calopterygidae). Adult C. splendens specimens were collected at three study sites along the trophic gradient of the Tisza River in Hungary and Ukraine. Body and abdomen length, head width, and distances between wing landmarks were assessed as metric traits, and the number of wing cells as meristic traits. The concentration of chlorophyll‐a was used to classify the three study sites into having a low, intermediate, and high trophic condition based on earlier studies. Significant differences were found along the trophic gradient based on the measured metric and meristic traits. Especially, insects from the site with the highest trophic condition had the largest body length, head width, and distances between wing landmarks, as well as the highest number of cells in the fore wings. There were also differences between males and females, but we did not find differences in fluctuating asymmetry (FA), i.e., differences between the left and the right wings. These results indicated that the morphological traits of adult banded demoiselles could be indicative of the environmental quality of a watercourse. [ABSTRACT FROM AUTHOR]

Heterospecific interactions are an important phenomenon of animal epigamic behaviour; however, they remain understudied within important groups, such as insects. Dragonflies are an ideal group for research on interspecific mating and possible hybridisation as they are easily identifiable, large insects, with a conspicuous mating process, often striking territorial behaviour and several mating systems.Using the genus Sympetrum as the model group, we examined heterospecific mating at three different levels. In the field, we identified whether species identity, time and weather affected heterospecific mating frequency. One important part of heterospecific mating is whether the process is completed. For dragonflies, this means that flying in tandem is followed by successful copulation, gamete fusion and oviposition (which comprise mating completeness). In a mesocosm experiment, we determined mating completeness (tandems, copulation, oviposition) of hetero‐ and homospecific pairs and the possible role of species density in heterospecific mating. In the laboratory, we compared the viability of the offspring from heterospecific pairs with different epigamous behaviour.We found heterospecific mating to be a relatively common phenomenon unaffected by environmental variables, that was primarily influenced by species identity, temporal distribution and abundance of dragonfly species. Consequently, the presence of counterparts of other species is the main predictor of the frequency of heterospecific mating.The probability of completed epigamic behaviour (copulation and subsequent oviposition) connected with gamete fusion is lower in heterospecific mating. Generally, based on our results we can assume that successful heterospecific mating (leading to gamete fusion) occurs in closely related species (e.g., Sympetrum striolatum and Sympetrum vulgatum). However, as pre‐copulatory barriers are not strongly developed in some dragonfly groups, less closely related species (e.g., Sympetrum sanguineum and S. striolatum) also may mate. This phenomenon requires further study as it may present a threat to the survival of some species in the context of changing environmental conditions, including climate change. [ABSTRACT FROM AUTHOR]

Our understanding of how biotic interactions influence animal community assembly is largely restricted to local systems due to the difficulty of obtaining ecologically meaningful assemblage data across large spatial extents. Here, we used thousands of spatio‐phenologically high‐resolution assemblages across three distinct European regions together with a functional diversity approach to understand community assembly of dragonflies and damselflies (Odonata), an insect group characterized by a pronounced competitive reproductive biology. We found that adult dragonfly, but not damselfly, assemblages were consistently composed of species morphologically more different than expected by chance based on the traits that enhance their interspecific reproductive encounters. These results provide consistent evidence for the role of competition in the assembly of animal communities, which we interpret is most likely caused by the territorial reproductive biology of dragonflies. Support for competition varied both spatially and seasonally following theoretical expectations, as it was strongest in locations and seasonal moments with low thermal stress (i.e. warm conditions) and high niche packing. Our study illustrates how spatio‐temporal diversity patterns arise from variation in assembly processes. [ABSTRACT FROM AUTHOR]

Urbanisation continues to increase at an alarming rate and its effects on the natural environment are very profound now more than ever. Moreover, studies on terrestrial urban landscapes seems to be more than that on urban freshwater habitats. Furthermore, studies have shown that the Odonata are effective indicators of the effects of urbanisation on freshwater habitats. However, not much is known about their responses to urbanisation in sub-Saharan Africa, especially given the unique set of conditions that characterise the area. Therefore, this study was conducted to investigate differences in Odonata responses, measured as the proportion of habitat generalists, to three levels of habitat disturbance in the Cape Coast Metropolis of Ghana. Results showed that Phaon camerunensis was a potential indicator of habitat disturbance. Also, differences in habitat disturbance significantly affected Odonata composition. The most important variables that influenced Odonata responses were the individual and interaction effects of altitude and preservation of riparian vegetation. Therefore, conservation strategies that are targeted at reducing the impacts of urbanisation on Odonata must focus on these variables. [ABSTRACT FROM AUTHOR]

The evolution of reproductive barriers, that is, the speciation process, implies the limitation of gene flow between populations. Different patterns of genomic differentiation throughout the speciation continuum may provide insights into the causal evolutionary forces of species divergence. In this study, we analysed a cryptic species complex of the genus Hetaerina (Odonata). This complex includes H. americana and H. calverti; however, in H. americana two highly differentiated genetic groups have been previously detected, which, we hypothesize, may correspond to different species with low morphological variation. We obtained single nucleotide polymorphism (SNP) data for 90 individuals belonging to the different taxa in the complex and carried out differentiation tests to identify genetic isolation. The results from STRUCTURE and discriminant analysis of principal components (DAPC), based on almost 5000 SNPs, confirmed the presence of three highly differentiated taxa. Also, we found FST values above 0.5 in pairwise comparisons, which indicates a considerable degree of genetic isolation among the suggested species. We also found low climatic niche overlap among all taxa, suggesting that each group occurs at specific conditions of temperature, precipitation and elevation. We propose that H. americana comprises two cryptic species, which may be reproductively isolated by ecological barriers related to niche divergence, since the morphological variation is minimal and, therefore, mechanical barriers are probably less effective compared to other related species such as H. calverti. [ABSTRACT FROM AUTHOR]

Understanding species distributions and predicting future range shifts requires considering all relevant abiotic factors and biotic interactions. Resource competition has received the most attention, but reproductive interference is another widespread biotic interaction that could influence species ranges. Rubyspot damselflies (Hetaerina spp.) exhibit a biogeographic pattern consistent with the hypothesis that reproductive interference has limited range expansion. Here, we use ecological niche models to evaluate whether this pattern could have instead been caused by niche differentiation. We found evidence for climatic niche differentiation, but the species that encounters the least reproductive interference has one of the narrowest and most peripheral niches. These findings strengthen the case that reproductive interference has limited range expansion and also provide a counterexample to the idea that release from negative species interactions triggers niche expansion. We propose that release from reproductive interference enables species to expand in range while specializing on the habitats most suitable for breeding. [ABSTRACT FROM AUTHOR]

Competition should play a key role in shaping community assembly and thereby local and regional biodiversity patterns. However, identifying its relative importance and effects in natural communities is challenging because theory suggests that competition can lead to different and even opposing patterns depending on the underlying mechanisms. Here, we have taken a different approach: rather than attempting to indirectly infer competition from diversity patterns, we compared trait diversity patterns in odonate (dragonfly and damselfly) communities across different spatial and temporal scales along a natural competition–predation gradient. At the local scale (within a community), we found that trait diversity increased with the size of top predators (from invertebrates to fish). This relationship is consistent with differences in taxonomic diversity, suggesting that competition reduces local trait diversity through competitive exclusion. Spatial (across communities) and temporal (within communities over time) trait variation peaked in communities with intermediate predators indicating that both high levels of competition or predation select for trait convergence of communities. This indicates that competition acts as a deterministic force that reduces trait diversity at the local, regional, and temporal scales, which contrasts with patterns at the taxonomic level. Overall, results from this natural experiment reveal how competition and predation interact to shape biodiversity patterns in natural communities across spatial and temporal scales and provide new insights into the underlying mechanisms. [ABSTRACT FROM AUTHOR]

Despite being central to the implementation of conservation policies, the usefulness of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species is hampered by the 14% of species classified as data‐deficient (DD) because information to evaluate these species' extinction risk was lacking when they were last assessed or because assessors did not appropriately account for uncertainty. Robust methods are needed to identify which DD species are more likely to be reclassified in one of the data‐sufficient IUCN Red List categories. We devised a reproducible method to help red‐list assessors prioritize reassessment of DD species and tested it with 6887 DD species of mammals, reptiles, amphibians, fishes, and Odonata (dragonflies and damselflies). For each DD species in these groups, we calculated its probability of being classified in a data‐sufficient category if reassessed today from covariates measuring available knowledge (e.g., number of occurrence records or published articles available), knowledge proxies (e.g., remoteness of the range), and species characteristics (e.g., nocturnality); calculated change in such probability since last assessment from the increase in available knowledge (e.g., new occurrence records); and determined whether the species might qualify as threatened based on recent rate of habitat loss determined from global land‐cover maps. We identified 1907 species with a probability of being reassessed in a data‐sufficient category of >0.5; 624 species for which this probability increased by >0.25 since last assessment; and 77 species that could be reassessed as near threatened or threatened based on habitat loss. Combining these 3 elements, our results provided a list of species likely to be data‐sufficient such that the comprehensiveness and representativeness of the IUCN Red List can be improved. [ABSTRACT FROM AUTHOR]

The probability of occurrence of a given species in a target locality and assemblage is conditioned not only by environmental/climatic variables but also by the presence of other species (i.e., species co‐occurrence). This framework, already complex in nature, becomes even more complicated if one considers the functional traits of species that, in turn, might influence the structure of metacommunities in various ways. Depending on the ecological and environmental setting, functional similarity (i.e., convergence in morphological and ecological traits) between species might either reduce their co‐occurrence due to high niche overlap driving negative interactions or promote it if the similar traits are associated with local habitat suitability. Similarly, functional divergence might either promote species co‐occurrence by limiting negative interactions through niche separation or reduce it through trait mediated environmental filtering. Therefore, discriminating between these alternative scenarios—predicting whether two species will tend to co‐occur or not based on their traits—is extremely challenging. Here, we develop a novel protocol to tackle the challenge, and we demonstrate its effectiveness by showing that ecological species traits can predict species co‐occurrence in a large dataset of North American Odonata. To this end, we first used the Hierarchical Modeling of Species Communities framework to quantify the pairwise species co‐occurrence after controlling for environmental and climatic factors. Then, we used machine learning to generate models which proved capable of predict accurately the observed co‐occurrence patterns from species functional traits. Our approach offers a generalizable analytical framework with the potential to clarify long‐standing ecological questions. [ABSTRACT FROM AUTHOR]

Using recently published chromosome‐length genome assemblies of two damselfly species, Ischnura elegans and Platycnemis pennipes, and two dragonfly species, Pantala flavescens and Tanypteryx hageni, we demonstrate that the autosomes of Odonata have undergone few fission, fusion, or inversion events, despite 250 million years of separation. In the four genomes discussed here, our results show that all autosomes have a clear ortholog in the ancestral karyotype. Despite this clear chromosomal orthology, we demonstrate that different factors, including concentration of repeat dynamics, GC content, relative position on the chromosome, and the relative proportion of coding sequence all influence the density of syntenic blocks across chromosomes. However, these factors do not interact to influence synteny the same way in any two pairs of species, nor is any one factor retained in all four species. Furthermore, it was previously unknown whether the micro‐chromosomes in Odonata are descended from one ancestral chromosome. Despite structural rearrangements, our evidence suggests that the micro‐chromosomes in the sampled Odonata do indeed descend from an ancestral chromosome, and that the micro‐chromosome in P. flavescens was lost through fusion with autosomes. [ABSTRACT FROM AUTHOR]

Libellula angelina is an endangered dragonfly species that is native to East Asia. Recently, their population has become severely reduced through habitat loss. To protect L. angelina populations, we need to understand which factors determine their distribution and how their potential habitats will change in the future. In this study, the habitat preference of L. angelina was identified through field surveys, and the potential distribution of L. angelina and the impact of integrated climate–land cover changes were simulated using the MaxEnt model. Furthermore, the wetland loss scenario was applied to areas where the current trend in wetland loss will continue in the future. The field survey identified that L. angelina prefers small inland wetlands: permanent freshwater, ponds; permanent rivers, ponds; irrigated land; and estuarine waters. From the MaxEnt results, altitude was the variable with the greatest contribution and distance from wetlands was the most unique variable. MaxEnt described the geographic pattern of occurrences under the current climate well, with few areas requiring any further survey. In the future projection, the potential habitat area was increased by up to 48.8% and 30.6% in the 2050s and 2080s, respectively. However, potential habitat loss was expected if wetlands continue to decline as they have done in the last 20 years. The wetland loss scenario resulted in potential habitat losses of 1.9%–2.3% and 4.5%–6.1% in the 2050s and 2080s, respectively. Therefore, to protect L. angelina populations we must minimize the loss of current populations, secure wetlands and strengthen the connectivity between wetlands. [ABSTRACT FROM AUTHOR]

Developmental plasticity can help organisms to survive in temporally variable environments. However, it is not well understood how variation in life history plasticity helps species coexist in heterogeneous environments. Here, we investigate the extent to which life‐history plasticity explains species distributions in a diverse assemblage of odonates in a tropical freshwater rock pool system characterized by substantial variation in pond permanence. Some dragonflies and damselflies (Odonata) can accelerate their development to leave the water before their habitat dries. However, how they sense habitat drying is poorly understood.Here, we experimentally tested the extent to which elevated concentrations of salts in water or reductions in water level can be used as cues for developmental acceleration in a neotropical Odonata assemblage from granite rock pools.Libellulidae dragonflies were found along the permanence gradient and accelerated their growth in response to elevated dissolved salts (measured as conductivity). Anax amazili (Aeshnidae) was also found in all environments and did the same in response to lower water levels. In turn, larvae of the damselfly Telebasis simulata (Coenagrionidae) were restricted to deeper long‐lived pools and did not respond to the tested cues.Differentiation in life‐history strategies can contribute to niche differentiation in this diverse predator assemblage. Developmental plasticity triggered by different cues helps odonates avoid mortality and exploit short‐lived habitats. The global acceleration of freshwater salinisation due to human activities might disrupt the delicate links between low levels of dissolved salts and life‐history responses and represent a significant threat to these ecosystems and their biodiversity. [ABSTRACT FROM AUTHOR]

As global climate continues to change, so too will phenology of a wide range of insects. Changes in flight season usually are characterised as shifts to earlier dates or means, with attention less often paid to flight season breadth or whether seasons are now skewed. We amassed flight season data for the insect order Odonata, the dragonflies and damselflies, for Norway over the past century‐and‐a‐half to examine the form of flight season change. By means of Bayesian analyses that incorporated uncertainty relative to annual variability in survey effort, we estimated shifts in flight season mean, breadth, and skew. We focussed on flight season breadth, positing that it will track documented growing season expansion. A specific mechanism explored was shifts in voltinism, the number of generations per year, which tends to increase with warming. We found strong evidence for an increase in flight season breadth but much less for a shift in mean, with any shift of the latter tending toward a later mean. Skew has become rightward for suborder Zygoptera, the damselflies, but not for Anisoptera, the dragonflies, or for the Odonata as a whole. We found weak support for voltinism as a predictor of broader flight season; instead, voltinism acted interactively with use of human‐modified habitats, including decrease in shading (e.g. from timber extraction). Other potential mechanisms that link warming with broadening of flight season include protracted emergence and cohort splitting, both of which have been documented in the Odonata. It is likely that warming‐induced broadening of flight seasons of these widespread insect predators will have wide‐ranging consequences for freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Dragonfly and damselfly larvae (Insecta: Odonata) capture prey by rapid protraction of a raptorial mouthpart, based on a modified labium. Yet, in insects with biting‐chewing mouthparts, the labium has an essential role in food handling. These two distinct functions ‐prey capturing and handling—lead to a mechanical problem in Odonata larvae: while the labium is always protracted in a straight line during prey capture, food handling requires more dexterity. In this study, we investigate the role of the labium in the feeding process and analyse the mechanics of the labial joints in the dragonfly larva Anax imperator. Our results show that the labium features a multiaxial joint connecting the basal segment (postmentum) and the head. During feeding, a combination of rotations around different axes is used to handle and orient prey, which is unique among biting‐chewing mouthparts. Furthermore, we identified structures at the joint which likely restrict lateral motion during the predatory strike. Our results provide a further understanding of the unique prey‐capturing apparatus of odonate larvae capable of controlling a 'switchable' multiaxial to a restricted monoaxial joint. This concept highlights the evolution of a highly modified raptorial mouthpart appendage where the degrees of freedom can be actively restricted to allow for the respectively needed functionality. Research Highlights: Kinematics and functionality of the raptorial appendage in odonate larvae at joint level First assess to the multifunctionality of the prehensile labial mask Presenting a 'switchable' multiaxial to restricted monoaxial joint [ABSTRACT FROM AUTHOR]

These observations add a unique example of predator-prey reversal that is dependent on life stage and shifts from dragonfly larva eating tadpoles in the aquatic environment to frogs eating dragonflies in the terrestrial environment (Figure 2). First, the green and golden bell frog often selects predator-free ephemeral wetlands to avoid heavy tadpole mortality by predators such as dragonfly larvae (Beranek, Sanders, et al., [6]). Keywords: amphibian; diet; odonata; predation; predator-prey dynamics; wetlands EN amphibian diet odonata predation predator-prey dynamics wetlands 1 6 6 08/03/23 20230801 NES 230801 INTRODUCTION There are many documented instances of "predator-prey reversal", which is a biological interaction where an organism that is typically thought of as prey in a pairwise predator-prey interaction instead acts as the predator at a different age or life stage (Barkai & Mcquaid, [1]), such as when adults of a prey species opportunistically prey on their predator's young. To address these knowledge gaps, we recommend a follow-up study where frogs undergo gastric lavage during periods of high dragonfly metamorph emergence (October and November) and compare this to periods of low dragonfly metamorph emergence (February and March). [Extracted from the article]

Aim: Understanding biodiversity patterns is crucial for prioritizing future conservation efforts and reducing the current rates of biodiversity loss. However, a large proportion of species remain undescribed (i.e. unknown biodiversity), hindering our ability to conduct this task. This phenomenon, known as the 'Linnean shortfall', is especially relevant in highly diverse, yet endangered, taxonomic groups, such as insects. Here we explore the distributions of recently described freshwater insect species in Europe to (1) infer the potential location of unknown biodiversity hotspots and (2) determine the variables that can anticipate the distribution of unknown biodiversity. Location: The European continent, including western Russia, Cyprus and Turkey. Methods: Georeferenced information of all sites where new aquatic insect species were described across Europe from 2000 to 2020 was compiled. In order to understand the observed spatial patterns in richness of recently described species, spatial units were defined (level 6 of HydroBASINS) and associated with a combination of a set of socioeconomic, environmental and sampling effort descriptors. A zero‐inflated Poisson regression approach was used to model the richness of newly described species within each spatial unit. Results: Nine hundred and sixty‐six recently described species were found: 398 Diptera, 362 Trichoptera, 105 Coleoptera, 66 Plecoptera, 28 Ephemeroptera, 3 Neuroptera, 2 Lepidoptera and 2 Odonata. The Mediterranean Basin was the region with the highest number of recently described species (74%). The richness of recently described species per spatial unit across Europe was highest at mid‐elevation areas (between 400 and 1000 m), latitudes between 40 and 50° and in areas with yearly average precipitation levels of 500–1000 mm, a medium intensity of sampling effort and low population density. The percentage of protected areas in each study unit was not significantly related to the richness of recently described species. In fact, 70% of the species were found outside protected areas. Main conclusions: The results highlight the urgent need to concentrate conservation efforts in freshwater ecosystems located at mid‐altitude areas and out of protected areas across the Mediterranean Basin. The highest number of newly described species in those areas indicates that further monitoring efforts are required to ensure the aquatic biodiversity is adequately known and managed within a context of growing human impacts in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Dragonfly/damselfly naiads have the potential to control mosquitoes, and indirectly the diseases they carry, due to their extensive predation on mosquito larvae. Experimental studies have measured the effectiveness of individual dragonfly/damselfly naiads in controlling mosquitoes by introducing them to mosquito larvae and counting the number of larvae eaten in a given time period (i.e. predation success).Without a quantitative synthesis, however, such individual measures are unable to provide a generalized estimation about the effectiveness of dragonflies/damselflies as biological mosquito control agents. To achieve this, we assembled a database containing 485 effect sizes across 31 studies on predation successes of 47 species of commonly found dragonfly/damselfly naiads on nine species of mosquito larvae belonging to Aedes, Anopheles and Culex. These studies covered 14 countries across Asia, Africa and South and North America, where mosquitoes are the vectors of Chikungunya, Dengue, Japanese encephalitis, Lymphatic filariasis, Malaria, Rift Valley fever, West Nile fever, Yellow fever and Zika.Using this database, we conducted a meta‐analysis to estimate the average predation success per day by a single individual dragonfly/damselfly naiad on these mosquito larvae as a generalized measure of the effectiveness of dragonflies/damselflies for mosquito control. We also built an interaction network for predator‐dragonflies/damselflies and prey‐mosquitoes and the diseases they vector to understand the functioning of this important predator‐prey network.Our results showed that mosquito larvae were significantly reduced through predation by dragonfly/damselfly naiads. Within experimental containers, a single individual dragonfly/damselfly naiad can eat on average 40 (95% confidence intervals [CIs] = 20, 60) mosquito larvae per day, equivalent to a reduction of the mosquito larval population by 45% (95% CIs = 30%, 59%) per day. The average predation success did not significantly vary among Aedes, Anopheles and Culex mosquitoes or among the four (I–IV) mosquito larval stages.These results provide strong evidence that dragonflies/damselflies can be effective biological control agents of mosquitoes, and environmental planning to promote them could lower the risk of spreading mosquito‐borne diseases in an environmentally friendly and cost‐effective manner. [ABSTRACT FROM AUTHOR]

Aim: To project the impact of climate change on dragonfly and damselfly diversity in West and Central Asia. Location: West and Central Asia. Time period: 1900–2020 data used to predict distributions in 2070 and 2100. Taxon studied: Odonata. Methods: Based on 149,001 records, distribution models were created for 159 species using MaxEnt. Environmental variables consisted of climate variables taken from BIOCLIM, river data and soil data. The future climate data were obtained from CHELSA from CMIP6 climate models. The same variables were collected for three scenarios (SSP1‐2.6, SSP3‐7.0 and SSP5‐8.5) of shared socioeconomic pathways for the years 2050–2070 and 2080–2100. For each scenario and period, diversity maps were prepared for six species groups: all species, Lentic, Lotic, Oriental, Afrotropical and Palaearctic species. Results: Strong declines in diversity are expected in western Turkey, the Levant and Azerbaijan, and to a lesser extent in parts of Iran and southern Central Asia. An increase is expected in eastern Turkey and at higher elevations in Central Asia with a limited increase throughout the Arabian Peninsula. In contrast to expectations, a decrease in areas with <15 species was found. Faunal composition is predicted to show strong shifts, with Palaearctic species declining and Oriental and Afrotropical species increasing. No clear difference between the trend of lentic and lotic species is found, although there are clear spatial differences in trend between these groups. Main Conclusions: Climate change will result in strong changes in diversity and distribution of dragonflies and damselflies in West and Central Asia with regional declines and increases. None of the species are predicted to go extinct based on the impact of climate change only, however, the combined impact of climate change and anthropogenic forces is likely to push some of the species to near extinction by 2100. [ABSTRACT FROM AUTHOR]

Sexual selection favours the evolution and maintenance of polygamy, which is the dominant reproductive strategy in insects. Monogamy can evolve in very short‐lived species due to time constraints. Here we study adult activity and mating behaviour of a population of the damselfly Ischnura hastata, a species rarely seen mating, and which has been suggested to be monandric, in wetlands of Isabela Island, Galápagos.By means of mark‐recapture methods, we estimated that the daily survival rate was low, ranging from 0.385 to 0.876, yielding average life expectancies of mature individuals of only 1.2–3.2 days. Adults showed very low activity before 7:00, indicating that mating does not occur early. The number of male–female interactions and mating attempts was extremely low, with only 44 copulations recorded on over 230 h of observations.Copulations were brief, with a mean duration of 11 min (but only two were observed from the start). Males showed clear preference to attempt to grasp in tandem females of intermediate age (in 94.3% of cases), rather than young (31.3%) or mature females (24.0%). Males were very persistent once a tandem was achieved, retaining females for up to 139 min, but most females resisted and did not copulate.We conclude that females of I. hastata show a very short time window to mate, exactly when they change colour from juvenile to mature, and live only enough to mate once. Short lifespan has selected for female monandry in I. hastata, creating an intense sexual conflict over mating rates. [ABSTRACT FROM AUTHOR]

Historical data on co‐occurring taxa are extremely rare. As such, the extent to which distinct co‐occurring taxa experience similar long‐term patterns in species richness and compositional change (e.g., when exposed to a changing environment) is not clear. Using data from a diverse ecological community surveyed in the 1930s and resurveyed in the 2010s, we investigated whether local plant and insect assemblages displayed cross‐taxon congruence—that is, spatiotemporal correlation in species richness and compositional change—across six co‐occurring taxa: vascular plants, non‐vascular plants, grasshoppers and crickets (Orthoptera), ants (Hymenoptera: Formicinae), hoverflies (Diptera: Syrphidae), and dragonflies and damselflies (Odonata). All taxa exhibited high levels of turnover across the ca. 80‐year time period. Despite minimal observed changes at the level of the whole study system, species richness displayed widespread cross‐taxon congruence (i.e., correlated temporal change) across local assemblages within the study system. Hierarchical logistic regression models suggest a role for shared responses to environmental change underlying cross‐taxon correlations and highlight stronger correlations between vascular plants and their direct consumers, suggesting a possible role for biotic interactions between these groups. These results provide an illustration of cross‐taxon congruence in biodiversity change using data unique in its combination of temporal and taxonomic scope, and highlight the potential for cascading and comparable effects of environmental change (abiotic and biotic) on co‐occurring plant and insect communities. However, analyses of historical resurveys based on currently available data come with inherent uncertainties. As such, this study highlights a need for well‐designed experiments, and monitoring programs incorporating co‐occurring taxa, to determine the underlying mechanisms and prevalence of congruent biodiversity change as anthropogenic environmental change accelerates apace. [ABSTRACT FROM AUTHOR]

Discussion regarding the gaps of knowledge on Odonata is common in the literature. Such gaps are even greater when dealing with basic biological data for biodiverse environments like the Amazon Rainforest. Therefore, studies that address, classify, and standardize functional traits allow the elaboration of a wide range of ecological and evolutionary hypotheses. Moreover, such endeavors aid conservation and management planning by providing a better understanding of which functional traits are filtered or favored under environmental changes. Here, our main goal was to produce a database with 68 functional traits of 218 Odonata species that occur in the Brazilian Amazon. We extracted data on behavior, habit/habitat (larvae and adults), thermoregulation, and geographic distribution from 419 literature sources classified into different research areas. Moreover, we measured 22 morphological traits of approximately 2500 adults and categorized species distributions based on approximately 40,000 geographic records for the Americas. As a result, we provided a functional matrix and identified different functional patterns for the Odonata suborders, as well as a strong relationship between the different trait categories. For this reason, we recommend the selection of key traits that represent a set of functional variables, reducing the sampling effort. In conclusion, we detect and discuss gaps in the literature and suggest research to be developed with the present Amazonian Odonata Trait Bank (AMO‐TB). [ABSTRACT FROM AUTHOR]

Aim: So far, latitudinal body size clines have been discussed primarily in the context of thermoregulation, sensu Bergmann. However, body size patterns are ambiguous in ectotherms, and this heterogeneity remains poorly understood. We tested whether Bergmann's rule and the resource availability rule, which states that energetic requirements determine species body size, apply to damselflies and dragonflies (Odonata). Furthermore, we hypothesized that the contrasting effects of thermoregulation and resource availability (e.g., productivity) can obscure the overall gradient in body size variation. Location: Global. Time period: Contemporary. Major taxa studied: Odonata. Methods: Using data for 43% of all odonate species described so far, we tested our hypotheses in phylogenetically and spatially comparative analyses at assemblage and species levels. For the distribution data, we integrated expert range maps and ecoregional ranges based on all available occurrence records. To distinguish between long‐term and evolutionarily recent responses of environmental drivers in body size, we constructed a phylogenetically informed classification of all odonate species and decomposed the body size into its phylogenetic and specific components for our subset of species. Results: We documented a weak positive relationship between body length and latitude but found strong and contrasting effects for temperature between dragonflies and damselflies and consistent positive effects for productivity that explained 35–57% of body size variation. Moreover, we showed a strong phylogenetic signal in sized‐based thermoregulation that shaped the distribution of dragonflies, but not of damselflies. Main conclusions: We concluded that temperature, productivity and conservatism in size‐based thermoregulation synergistically determine the distribution of ectotherms, while the taxon‐specific importance of these factors can lead to contrasting and weak latitude–size relationships. Our results reinforce the importance of body size as a determinant of species distributions and responses to climate change. [ABSTRACT FROM AUTHOR]

Motivation: Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological studies and applied freshwater research is missing. We aim to fill this gap and present the Global EPTO Database, which includes worldwide geo‐referenced aquatic insect occurrence records for four major taxa groups: Ephemeroptera, Plecoptera, Trichoptera and Odonata (EPTO). Main type of variables contained: A total of 8,368,467 occurrence records globally, of which 8,319,689 (99%) are publicly available. The records are attributed to the corresponding drainage basin and sub‐catchment based on the Hydrography90m dataset and are accompanied by the elevation value, the freshwater ecoregion and the protection status of their location. Spatial location and grain: The database covers the global extent, with 86% of the observation records having coordinates with at least four decimal digits (11.1 m precision at the equator) in the World Geodetic System 1984 (WGS84) coordinate reference system. Time period and grain: Sampling years span from 1951 to 2021. Ninety‐nine percent of the records have information on the year of the observation, 95% on the year and month, while 94% have a complete date. In the case of seven sub‐datasets, exact dates can be retrieved upon communication with the data contributors. Major taxa and level of measurement: Ephemeroptera, Plecoptera, Trichoptera and Odonata, standardized at the genus taxonomic level. We provide species names for 7,727,980 (93%) records without further taxonomic verification. Software format: The entire tab‐separated value (.csv) database can be downloaded and visualized at https://glowabio.org/project/epto%5fdatabase/. Fifty individual datasets are also available at https://fred.igb‐berlin.de, while six datasets have restricted access. For the latter, we share metadata and the contact details of the authors. [ABSTRACT FROM AUTHOR]

Strong biodiversity declines have been reported across the European Union, especially in insects, despite conservation policy such as the Habitats Directive that aims to halt biodiversity loss. Using 50 years of observational data, we examined indicators for the goals of the Directive in terms of improving monitoring efforts and occupancy trends of butterfly and dragonfly annex species in a central European region. We quantified annual monitoring effort and used occupancy‐detection models to compare species trends for 18 years before and after legal implementation of the Directive. Monitoring efforts increased after implementation, while occupancy trends both improved and deteriorated. Contrary to its main goal, the European Habitats Directive did not prevent a worsening of all annex species' occupancy trends in the studied region. While the increased monitoring efforts aid biodiversity assessments, more serious broad‐scale conservation measures are needed to halt biodiversity loss across Europe. [ABSTRACT FROM AUTHOR]

Aim: Understanding the mechanisms underlying the structure and connectivity of ecological communities is a central issue in biogeography. Dispersal syndromes are tightly woven into organisms' life history seen across populations and communities, but measuring dispersal is still complicated in practice. We investigated the role of dispersal syndromes (here, associated with body size, adult flying ability and voltinism) to predict phylogenetic distance decay relationships (DDRs) of aquatic insect assemblages in dendritic stream networks. Location: Du River Basin, China. Taxon: Aquatic insects (Coleoptera, Diptera, Ephemeroptera, Hemiptera, Lepidoptera, Megaloptera, Odonata, Plecoptera and Trichoptera). Methods: We applied multiple methods (i.e. deconstruction approach, null models, Mantel tests and partial Mantel tests) to enhance our basic understanding of phylogenetic distance decay patterns. To provide additional insights into correlates of phylogenetic dissimilarity between stream sites, we modelled potential dispersal routes based on overland, watercourse and cost distances. Results: Overland distances were among the main correlates of phylogenetic distance decay in the stream networks studied, suggesting that aquatic insects disperse overland seeking for habitats suitable for survival and reproduction. However, local environmental filtering was generally more important for phylogenetic DDRs than geographical distances alone. The interaction between environmental vs. dispersal processes in driving spatial patterns of phylogenetic dissimilarity was contingent on different dispersal syndromes. More specifically, significant phylogenetic DDRs were detected only for subsets of large‐bodied, univoltine taxa with strong adult flying abilities, such as dragonflies. Main Conclusions: Overall, historical constraints affect the phylogenetic DDRs in aquatic insects. Dispersal syndromes associated with body size, adult flying ability and voltinism are key features underlying distance decay in phylogenetic assemblage similarity and the evolutionary legacies of aquatic insects in dendritic stream networks. [ABSTRACT FROM AUTHOR]

Species shifting their ranges under climate change are a conservation dilemma. Range‐shifters may be threatened by climate change in their historic range. However, range‐shifters are likely to be generalist opportunists, which could mean they could harm aspects of biodiversity in their new ecosystems. Therefore, we need approaches to rapidly assess how range‐shifters may integrate into the community of historically resident species.The small red‐eyed damselfly (Erythromma viridulum) has shifted into the United Kingdom since 1999 and may affect resident Odonata via intraguild predation. We asked whether the damselfly's arrival is associated with a decline in resident Odonata.We harnessed the British Dragonfly Society's dataset, using records from 49,788 site visits between 2000 and 2015 to construct dynamic species occupancy models for 17 resident UK Odonata. We estimated the potential effect of E. viridulum presence on the probability that each species would persist at a given site, while controlling for potential effects of climate and recording effort.On average, dragonflies (Anisoptera) persisted more frequently at sites where E. viridulum had established, while damselflies (Zygoptera) showed no change in persistence. Nevertheless, two resident damselflies, including E. viridulum's congener, disappeared more frequently when the range‐shifter established.We suggest that E. viridulum poses minimal risk to most UK resident Odonata. Rather, E. viridulum may be differentially establishing in areas with good habitat quality, where many species of historically resident Odonata are also found. Therefore, high quality, biodiverse sites may become home to increasing numbers of range‐shifters in future. Our approach permits rapid detection of how range‐shifters are integrating into resident biota. [ABSTRACT FROM AUTHOR]

Intensity and severity of bushfires in Australia have increased over the past few decades due to climate change, threatening habitat loss for numerous species. Although the impact of bushfires on vertebrates is well‐documented, the corresponding effects on insect taxa are rarely examined, although they are responsible for key ecosystem functions and services. Understanding the effects of bushfire seasons on insect distributions could elucidate long‐term impacts and patterns of ecosystem recovery.Here, the authors investigated the effects of recent bushfires, land‐cover change, and climatic variables on the distribution of a common and endemic dragonfly, the swamp tigertail (Synthemis eustalacta) (Burmeister, 1839), which inhabits forests that have recently undergone severe burning. The authors used a temporally dynamic species distribution modelling approach that incorporated 20 years of community‐science data on dragonfly occurrence and predictors based on fire, land cover, and climate to make yearly predictions of suitability. The authors also compared this to an approach that combines multiple temporally static models that use annual data.The authors found that for both approaches, fire‐specific variables had negligible importance for the models, while the percentage of tree and non‐vegetative cover were most important. The authors also found that the dynamic model outperformed the static ones, based on cross‐validation omission rate. Model predictions indicated temporal variation in area and spatial arrangement of suitable habitat, but no patterns of habitat expansion, contraction, or shifting.These results highlight not only the efficacy of dynamic modelling to capture spatiotemporal variables such as vegetation cover for an endemic insect species, but also provide a novel approach to mapping species distributions with sparse locality records. [ABSTRACT FROM AUTHOR]

The influence of diet and host specificity on the fecal microbiome of three adult dragonfly species, Pseudothemis zonata, Orthetrum lineostigma, and Orthetrum melania, was investigated. The fecal bacterial communities were analyzed using 16S rRNA gene sequencing, and stable isotope analysis was used to investigate their food sources. The results showed significant differences in the composition of fecal bacterial communities among the three species, with host specificity potentially playing a more important role than diet. The dominant phyla in the fecal bacterial communities of all three species were Firmicutes, Proteobacteria, and Bacteroidetes. The operational taxonomic units (OTUs), Shannon index, and phylogenetic diversity index were not significantly different among the three species, indicating that there were no major differences in the diversity of the fecal bacterial communities. The stable isotope analysis showed that the food sources were similar among the three species, being primarily small insects found near the aquatic habitats. However, the fecal bacterial communities of two closely related species, O. lineostigma and O. melania, were different despite their similar food sources. In contrast, the fecal bacterial communities of O. lineostigma and P. zonata were similar, despite the different food sources of these two species. Our findings suggest that host specificity and diet can influence the composition of the intestinal microbiome in these insects, but the degree of influence may depend on the specific host and environmental conditions. [ABSTRACT FROM AUTHOR]

Variation in body color occurs in many animals, and its function differs by species. Some species use multiple colors to create different effects. Most dragonflies change their body color unilaterally with maturation, whereas in a few species these changes are reversible. Both sexes of the damselfly Indolestes peregrinus show temperature‐dependent reversible body color changes, with a brown color when the ambient temperature decreases and a blue color when the temperature increases. To elucidate the temperature range at which this color change occurs and the exact elapsed time for the color change, laboratory experiments were conducted to determine whether the time required for body color change was related to ambient temperature and whether sex differences affected this duration. The body color and time required for the change were recorded under four temperature conditions. Bluing was completed in a few minutes, whereas browning took several hours. Moreover, sexual differences were observed, whereby males showed a more rapid transformation to blue than that of females. Our results suggest that the rapid bluing has some importance in this species, especially in males. [ABSTRACT FROM AUTHOR]

Aim: Global interspecific body size distributions have been suggested to be shaped by selection pressures arising from biotic and abiotic factors such as temperature, predation and parasitism. Here, we investigated the ecological and evolutionary drivers of global latitudinal size gradients in an old insect order. Location: Global. Taxon: Odonata (dragonflies and damselflies). Methods: We compiled data on interspecific variation in extant and extinct body sizes of Odonata, using an already existing database (The Odonate Phenotypic Database) and fossil data (The Paleobiology Database). We combined such body size data with latitudinal information and data on biotic and abiotic environmental variables across the globe to investigate and quantify interspecific latitudinal size‐gradients ("Bergmann's Rule") and their environmental determinants. We used phylogenetic comparative methods and a global published phylogeny of Odonata to address these questions. Results: Phylogenetic comparative analyses revealed that global size variation of extant Odonata taxa is negatively influenced by both regional avian diversity and temperature, with larger‐bodied species in the suborder Anisoptera (dragonflies) showing a steeper size‐latitude relationship than smaller‐bodied species in the suborder Zygoptera (damselflies). Interestingly, fossil data show that the relationship between wing size and latitude has shifted: latitudinal size trends had initially negative slopes but became shallower or positive following the evolutionary emergence and radiation of birds. Main Conclusions: The changing size‐latitude trends over geological and macroevolutionary time were likely driven by a combination of predation from birds and maybe pterosaurs and high dispersal ability of large dragonflies. Our study reveals that a simple version of Bergmann's Rule based on temperature alone is not sufficient to explain interspecific size‐latitude trends in Odonata. Our results instead suggest that latitudinal size gradients were shaped not only by temperature but also by avian predators, potentially driving the dispersal of large‐sized clades out of the tropics and into the temperate zone. [ABSTRACT FROM AUTHOR]

Global change may cause widespread phenological shifts. But knowledge of the extent and generality of these shifts is limited by the availability of phenological records with sufficiently large spatiotemporal extents. Using North American odonates (damselflies and dragonflies) as a model system, we show how a combination of natural history museum and community science collections, beginning in 1901 and extending through 2020, can be leveraged to better understand phenology.We begin with an analysis of odonate functional traits. Principal coordinate analysis is used to place odonate genera within a three‐dimensional trait ordination. From this, we identify seven distinct functional groups and select a single odonate genus to represent each group. Next, we pair the odonate records with a list of environmental covariates, including air temperature and degree days, photoperiod, precipitation, latitude and elevation. An iterative subsampling process is then used to mitigate spatiotemporal sampling bias within the odonate dataset. Finally, we use path analysis to quantify the direct effects of degree days, photoperiod and precipitation on odonate emergence timing, while accounting for indirect effects of latitude, elevation and year.Path models showed that degree days, photoperiod and precipitation each have a significant influence on odonate emergence timing, but degree days have the largest overall effect. Notably, the effect that each covariate has on emergence timing varied among functional groups, with positive relationships observed for some group representatives and negative relationships observed for others. For instance, Calopteryx sp. emerged earlier as degree days increased, while Sympetrum sp. emerged later.Previous studies have linked odonate emergence timing to temperature, photoperiod or precipitation. By using natural history museum and community science data to simultaneously examine all three influences, we show that systems‐level understanding of odonate phenology may now be possible. [ABSTRACT FROM AUTHOR]

Environmental and spatial heterogeneity affects the distribution of aquatic insects, determining or influencing the variation in local species composition. Dragonflies and damselflies (Odonata) have different strategies for oviposition site selection that depend on environmental conditions. However, Land Use and Land Cover (LULC) can reduce the availability of suitable sites for Odonata oviposition through environmental homogenization.We investigated the relationship between environmental and spatial heterogeneity and variation in species composition of Odonata with different oviposition strategies (endophytic, epiphytic and exophytic) in Amazonian streams in a gradient of LULC. We used the Jaccard and Bray‐Curtis coefficients and the Manhattan distance to estimate a continuum of variation in species composition.Variation in the composition of endophytic and epiphytic species was explained by spatial heterogeneity. Using abundance data and the Manhattan distance, we found a relationship between variation in species composition and environmental heterogeneity. Endophytic species composition was related to perch heterogeneity, while exophytic species composition was related to perch and canopy cover heterogeneity. Exophytic and endophytic species could be used in biomonitoring as they respond to specific environmental predictors and because exophytic species do not have spatial patterns across the landscape.Different dissimilarity coefficients provide complementary information about the responses of multispecies communities to land use, as some will represent strong effects (presence‐absence indexes) while others will represent more subtle effects (abundance‐based indexes). Land use can increase the environmental heterogeneity of some predictors (perches and canopy cover). Physical changes in streams such as hydromorphological alterations can modify specific habitats, affecting oviposition strategies and supporting tolerant species. [ABSTRACT FROM AUTHOR]

Andean wetlands in arid climates are isolated ecosystems surrounded by steep terrain and have crucial relevance as a water resource. The species inhabiting them are adapted to these habitats and vulnerable to environmental changes.The aim of this study is to evaluate the vulnerability of invertebrate aquatic species to climate change and organic pollution through an index adapted from the species distributional models (SDM) score [vulnerability of aquatic invertebrate species index (Vais)], and the vulnerability of the invertebrate communities through an index developed herein [wetland community vulnerability index (Wcv)].The Vais index ranges from 1 (highly vulnerable) to 0 (non‐vulnerable species). It was calculated for 22 species of the orders Coleoptera, Ephemeroptera, Hemiptera, and Odonata. According to our results, the most vulnerable species belong to the orders Ephemeroptera (2) and Odonata (8) (scores 0.63–0.76); species with medium vulnerability belong to the orders Coleoptera (1) Ephemeroptera (1), Hemiptera (4) and Odonata (1) (scores 0.43–0.54); and the most tolerant species belong to the orders Coleoptera (2) and Hemiptera (3) (0.31–0.29).The Wcv index was calculated for 31 communities in Andean wetlands. Lower Wcv values correspond to less vulnerable communities and higher values to more vulnerable communities. According to our results, communities can be divided into three groups: the most vulnerable (scores 0.61–0.71), the ones with medium vulnerability (scores 0.49–0.59), and the least vulnerable (scores 0.33–0.48).The Vais and Wcv indexes are useful tools for evaluating the vulnerability of aquatic species and wetland communities, providing valuable information for defining conservation strategies. [ABSTRACT FROM AUTHOR]

The use of mitochondrial markers for taxonomic identification and biodiversity monitoring is not without risks or limitations. Most importantly, the natural transfer of DNA from the mitochondria to the nucleus generates nonfunctional nuclear copies of mitochondrial DNA (NUMTs). Their abundance and size vary significantly among taxa, and NUMTs have been reported to complicate molecular studies based on mitochondrial markers in several insect orders, most prominently in Orthoptera. The significance of this phenomenon in Odonata has not yet been properly addressed. Here, we present a complete mitochondrial genome and a draft nuclear genome of Leucorrhinia albifrons (Odonata: Libellulidae), as well as NUMT and cox1 sequences from the related species Leucorrhinia dubia. We document the presence of NUMTs in the L. albifrons nuclear genome and in nuclear genomes of two other Odonata species available in public databases. Our results show that NUMTs can have a serious impact on barcoding, phylogenetic, population and phylogeographic studies of Odonata, especially when the barcode is located in the cox1 gene, the most frequently used molecular marker for Odonata. We suggest that nad1 should be used alone or in combination with cox1 to minimize unintended confusion with NUMTs. Finally, we present a mitophylogenomic analysis of Odonata and document several cases of misidentified mitochondrial genomes belonging to species different from those indicated in public databases. In conclusion, our findings represent an important step for future metabarcoding studies of Odonata based on mitochondrial DNA markers. [ABSTRACT FROM AUTHOR]

Globally, freshwater species are under threat from human mediated stressors. Therefore, there is an urgent need for methods to estimate population and species occurrences for conservation purposes. Here, we used a predictive species distribution model to determine the occurrence of three endangered species (Amietia inyangae, Chlorolestes elegans and Strongylopus rhodesianus) in Southern Africa (Eastern Highlands of Zimbabwe). The study revealed that the probability of occurrences for the three species increase with an increase in elevation and annual precipitation and decrease with an increase in annual mean temperature. Our results indicated that the highest probability of occurrences for A. inyange, C. elegans and S. rhodesianus is in the Nyanga, Stapleford and Chimanimani highland areas, with some probabilities of occurrence falling outside protected areas. Our findings suggest that the areas covered by protected areas may need to be revaluated. Our findings will be useful for managing threatened species. [ABSTRACT FROM AUTHOR]