Across complex landscapes, genetic structure can arise through a combination of geographic, ecological and historical processes. In mountain systems, isolation by distance (IBD), environment (IBE) and resistance (IBR) represent three such mechanisms but are often difficult to distinguish. The Great Dividing Range (GDR) of eastern Australia provides an ideal system for evaluating their relative contributions because of its varying elevation and climatic gradients. Here, we investigate the drivers of genetic structure in the Swamp Tigertail (Synthemis eustalacta) using an integrative framework combining population genomics, demographic analysis, morphology and ecological data. Results showed overall low genetic differentiation and no evidence for discrete population structure. Linear mixed-effects model provided no support for IBD but instead showed IBE and IBR, in which any observed genetic differentiation was correlated with environmental gradients, particularly precipitation and temperature extremes, vegetative cover and landscape resistance. Morphological analyses revealed minimal variation among sampled sites, but several traits were sexually dimorphic, suggesting potential sex-biased dispersal. Demographic reconstructions reveal long-term population stability, with paleoniche models displaying shifts in suitable habitat during past climatic oscillations. Together, these results highlight ecological and topographic isolation as key mechanisms shaping genetic variation in S. eustalacta and that montane dragonfly populations may maintain gene flow through climate cycles by tracking suitable conditions across elevational gradients rather than persisting in long-isolated refugia.

Panbiogeography has long been controversial due to its general rejection of both active dispersal as a key step that may lead directly to speciation, and the role of natural selection in evolution. As vicariance is the only means of speciation allowed within panbiogeography, montane taxa are assumed to have arrived at elevation through “passive uplift”. With one species found in high elevations of Kā Tiritiri-o-te-Moana (the Southern Alps) in Aotearoa (New Zealand), and another at lowland elevations, Kapokapowai dragonflies (genus Uropetala, family Petaluridae) are an excellent system for evaluating the hypothesis of passive uplift, and thus for evaluating the underlying assumptions of panbiogeography. Recent research on Kapokapowai, which employed demographic modelling from a reference genome assembly and assessment of population structure with sampling across the range of Kapokapowai dragonflies, strongly supports active colonization over passive uplift, showing evidence for a dynamic dispersal history with multiple active shifts between high and low elevations. Two subsequent publications have misrepresented this research and cited Kapokapowai as evidence that passive uplift is the primary means by which species come to inhabit alpine habitats. This is not supported by available data. Furthermore, under passive uplift, alpine Kapokapowai would have had to persist on Kā Tiritiri-o-te-Moana through multiple periods of glaciation, requiring persistence in a habitat in which, to our knowledge, no Petaluridae larvae have yet been observed. While vicariance can certainly result in speciation, the case of Kapokapowai dragonflies clearly demonstrates that the failure to consider dispersal can lead to an incomplete understanding of evolutionary histories.

The Vitiaz Arc provides a compelling opportunity to examine biogeographical patterns in the South Pacific. Previously, however, many groups lacked the appropriate taxon sampling to examine this system fully. Fieldwork aimed at improving our understanding of Vanuatu insect diversity and evolution resulted in the collection of two specimens of Melanesobasis bicellulare Donelly, 1984, a species previously known from a single specimen collected 40 years ago. Using a combination of morphological and molecular methods, we are able to associate the female, update distributional data, and record intraspecific variation, including the number of post-discoidal cells. We also use this genus, Melanesobasis Donnelly, 1984, found across Fiji and Vanuatu, to explore biogeographical patterns across the Vitiaz Arc. Our results provide additional evidence of the importance of the Vitiaz Arc in South Pacific damselfly biogeography and show a pattern of vicariance between the two island archipelagos.

Mountains and islands provide an opportunity for studying the biogeography of diversification and population fragmentation. Aotearoa (New Zealand) is an excellent location to investigate both phenomena due to alpine emergence and oceanic separation. While it would be expected that separation across oceanic and elevation gradients are major barriers to gene flow in animals, including aquatic insects, such hypotheses have not been thoroughly tested in these taxa. By integrating population genomic from subgenomic Anchored-Hybrid Enrichment sequencing, ecological niche modeling, and morphological analyses from scanning-electron microscopy, we show that tectonic uplift and oceanic vicariance are implicated in speciation and population structure in Kapokapowai (Uropetala) dragonflies. Although Te Moana o Raukawa (Cook Strait) is likely responsible for some of the genetic structure observed, speciation has not yet occurred in populations separated by the strait. We find that the altitudinal gradient across Kā Tiritiri-o-te-Moana (the Southern Alps) is not impervious, but it significantly restricts gene flow between the aforementioned species. Our data support the hypothesis of an active colonization of Kā Tiritiri-o-te-Moana by the ancestral population of Kapokapowai, followed by a recolonization of the lowlands. These findings provide key foundations for the study of lineages endemic to Aotearoa.

Neurocordulia, commonly called shadowdragons, are crepuscular dragonflies, flying mainly at dusk. The genus comprises seven species, which occur across the eastern part of Canada and the United States. Here, we used targeted enrichment probes to sequence ~1000 loci for all specimens of each species, allowing for the first phylogenetic assessment of the genus. Additionally, we collected individuals of N. yamaskanensis from a population in Ontario, Canada, and used whole genome resequencing to estimate population structure. Beyond broadly reconstructing the phylogeny of Neurocordulia, we provided a comprehensive bibliography review of past research on the genus, a key to the species, and distribution models for each species.

BackgroundHuman alteration of natural environments and habitats is a major driver of species decline. However, a handful of species thrive in human altered environments. The biology, distribution, population structure, and molecular adaptations enabling certain species to thrive in human-altered habitats are not well understood. Here, we evaluate the population and functional genomics, ecological niche and distributions, and geometric morphometrics of the blue dasher (Pachydiplax longipennis), one of the most ubiquitously observed insects in human altered habitats.ResultsUsing resequencing data we identify a number of genes involved with the success of the blue dasher in human altered habitats, including loci contributing to immune function and response to oxidative stress. Some genes related to these functions are found in regions of strong population structure, while others are not, potentially indicating both regional and widespread adaptations to urban environments within this species. Using one of the most robust locality datasets for any species to date, we also generate habitat suitability predictions which show that P. longipennis has spread with urbanization, suggesting humans have created suitable habitat for this species. These results complement morphological and genomic data showing P. longipennis (particularly East of the Rocky Mountains) has the capacity to rapidly disperse to newly suitable habitats.ConclusionsWe confirm that P. longipennis is well equipped to deal with the stress of urban habitats, by observing large swaths of suitable habitat of P. longipennis throughout its range, both within and outside of major cities and towns, and identifying conserved and population specific molecular mechanisms related to urban stress. Furthermore, we observe minor variability in suitable habitat of P. longipennis throughout the years; we do not note any substantial loss or gain in habitat, suggesting its resiliency to fluctuations in temperature and precipitation throughout the United States. Given the shared barriers to colonizing an urban habitat, we expect that many of the molecular adaptations to urban environments we have identified in P. longipennis could be found in other animals that are broadly tied to urban habitats.

Male territorial-sneaker polymorphisms are common in nature. To understand how these polymorphisms evolve, we developed a game theoretical model analogous to the classical Hawk-Dove model, but with two important differences. First, we allowed non-uniform interaction rates of strategies to account for the possibility that some interactions between male strategies are disproportionately more frequent than others. Second, we allowed females to exhibit a preference for one type of male and thereby choose mates adaptively. Selection dynamics were modeled using coupled replicator equations. The model confirms that there is a broad range of conditions under which a male polymorphism will arise. We applied the model to understand the genetic polymorphism in adult male Mnais damselflies (Zygoptera). Here, orange-winged adult males defend oviposition sites and mate with females when they arrive, while clear-winged 'sneaker' males are typically non-territorial and opportunistically mate with females. Intriguingly, in allopatry, the males of Mnais costalis and M. pruinosa both exhibit the same orange-clear winged polymorphism but where the species co-occur, males of M. costalis evolve orange wings while males of M. pruinosa tend to evolve clear wings. To understand this phenomenon and evaluate the importance of female choice in mediating it, we extended our game-theoretical model to two interacting species. While both competitive and reproductive interference can explain the male monomorphisms in sympatry, reproductive interference explains the phenomenon under a wider set of conditions. When females of the rarer species change their male preferences to facilitate species discrimination, it can generate runaway selection on male phenotypes.

Odonata is an insect order that comprises ~6420 described species distributed among three suborders. Here we review the dragonflies, or Anisoptera, a suborder which has 10 described families, and forms a sister group relationship with the ‘Anisozygoptera’ [Epiprocta: Anisoptera + ‘Anisozygoptera’], a paraphyletic grouping containing just one extant family and many extinct taxa. Dragonflies are charismatic, ancient, fast flying, predatory insects whose natural history is woven into the fabric of human culture. As objects of systematic study, their relative position in the insect tree of life relates to the origin of flight, of freshwater juvenile lifestyles, and the evolution of color and vision. In this paper, we will review the past, present, and future of Odonatology, highlighting the work being done all across the globe to revise and define the suborder Anisoptera. In particular, we focus on ‘problematic’ areas in the tree, the Gomphidae and Libellulidae, with an emphasis on how taxon and data sampling are solving these problems in the current global work.

The study of insect decline remains a major and increasingly urgent frontier in insect biodiversity and conservation. Despite increased attention to fluctuating insect decline trends, relatively little data have been compiled about aquatic insect species, particularly in urban ecosystems. Here, we combine environmental DNA (eDNA) metabarcoding and community science observations to monitor Odonata communities across an urban system in southwest Idaho, USA. We show that the distribution of Odonata communities across this urban landscape is not uniform, and that both monitoring methods have distinct strengths and limitations. Environmental DNA metabarcoding was sensitive to the detection of genera from underrepresented families in the region but was less effective at distinguishing closely related genera, particularly in sites where DNA degradation may have occurred. Community science observations effectively detected genera from more species-rich families but failed to capture relatively rare taxa or those with short flight periods. These findings highlight the complementary strengths of both methods: eDNA excels at detecting elusive or rare taxa in targeted sampling windows, while community science provides broader temporal coverage and finer taxonomic resolution. Integrating both methods offers a more robust approach to monitoring and managing urban biodiversity. In cases where only one method is employed, care should be taken to account for its inherent detection biases.

Nikoulabasis dalingarum sp. nov. (holotype male, Viti Levu, Fiji) is erected as a new taxon. Illustrations of key characters and a distribution map are provided.

Mountains and islands are both model systems for studying the biogeography of diversification and population fragmentation. Aotearoa is an excellent location to study both phenomena due to alpine emergence and oceanic separation. While it would be expected that separation across Te Moana o Raukawa and elevation gradients are major barriers to gene flow in aquatic insects, such hypotheses have not been thoroughly explored in these taxa. Here, we show that mountains and oceanic separation function as semi-permeable barriers for Kapokapowai dragonflies. We show that, although Te Moana o Raukawa, is likely responsible for some of the genetic structure observed, speciation has not yet occurred in populations separated by the strait. Although there is no evidence that they are an impervious barrier, Kā Tiritiri-o-te-Moana do represent a major barrier to gene flow between named species. The distribution of alpine Kapokapowai can also not be explained by the ancestral populations simply rising with the uplifted tectonic plates. Although further research is needed, our findings suggest that the ancestral Kapokapowai colonized alpine habitats after their formation, and then radiated back out to lowlands. These findings suggest that aquatic insects could be an exciting new frontier in the study of the biogeography of Aotearoa. ### Competing Interest Statement The authors have declared no competing interest.

The study of insect decline remains a major frontier in the study of insect biodiversity and conservation. Despite growing concern about the decline rates of insects generally, relatively little data has been compiled about species of aquatic insects. Data is particularly lacking on the distribution of aquatic insects in urban ecosystems. Here, we compare environmental DNA (eDNA) metabarcoding and community science observation as means of monitoring Odonata in an urban habitat in Southwest Idaho. We show that the distribution of Odonata across this urban landscape is not uniform and that both monitoring methods have different strengths and weaknesses. We found that eDNA metabarcoding was very sensitive to the identification of genera from underrepresented families in the region, but was unable to distinguish between closely related genera, particularly from localities where eDNA could accumulate more data. On the other hand, community science observations effectively identified the presence of genera from more speciose families but missed the presence of relatively rare species, and those that had a short flight season. These findings suggest that eDNA and community science are highly complementary of each other, but if only one method is going to be used for a monitoring or conservation project, care should be given to account for the biases of each approach. ### Competing Interest Statement The authors have declared no competing interest.

Petaluridae (Odonata: Anisoptera) is a relict dragonfly family, having diverged from its sister family in the Jurassic, of eleven species that are notable among odonates (dragonflies and damselflies) for their exclusive use of fen and bog habitats, their burrowing behavior as nymphs, large body size as adults, and extended lifespans. To date, several nodes within this family remain unresolved, limiting the study of the evolution of this peculiar family. Using an anchored hybrid enrichment dataset of over 900 loci we reconstructed the species tree of Petaluridae. To estimate the temporal origin of the genera within this family, we used a set of well-vetted fossils and a relaxed molecular clock model in a divergence time estimation analysis. We estimate that Petaluridae originated in the early Cretaceous and confirm the existence of monophyletic Gondwanan and Laurasian clades within the family. Our relaxed molecular clock analysis estimated that these clades diverged from their MRCA approximately 160 mya. Extant lineages within this family were identified to have persisted from 6 (Uropetala) to 120 million years (Phenes). Our biogeographical analyses focusing on a set of key regions suggest that divergence within Petaluridae is largely correlated with continental drift, the exposure of land bridges, and the development of mountain ranges. Our results support the hypothesis that species within Petaluridae have persisted for tens of millions of years, with little fossil evidence to suggest widespread extinction in the family, despite optimal conditions for the fossilization of nymphs. Petaluridae appear to be a rare example of habitat specialists that have persisted for tens of millions of years.

Disjunct biogeographic patterns of similar species remain enigmatic within evolutionary biology. Disparate distributions typically reflect species responses to major historical events including past climate change, tectonics, dispersal, and local extinction. Paleo-ecological niche modeling (PaleoENM) has proven useful in inferring the causes of disjunct distributions within charismatic and well-studied taxa including mammals, plants, and birds, but remains under-explored in insects. The relictual Asian dragonfly genus Epiophlebia (Suborder Epiophlebioptera: Epiophlebiidae) allows us a novel opportunity to explore PaleoENM in the context of disjunct distributions due to their endemism to the Japanese islands, Himalayas, China, and North Korea. The aim of this paper is to investigate the potential causes behind the modern distribution of Epiophlebia by inferring the historical range of these species within the Last Glacial Maximum (LGM), thereby highlighting the utility of PaleoENM in the context of odonate biogeography. Our results indicate possible past routes of gene flow of Epiophlebia during the LGM due to high habitat suitability of the genus stretching from the Himalayas to Japan. Furthermore, our results predict several unsampled areas which have the potential to harbor new populations of the genus.

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.

Biogeography-the study of the factors influencing the distribution of organisms in space and time-has a number of applications in modern research on odonates. Studies considering phylogenetic and geological information to infer past and extant patterns of biodiversity (known as historical biogeography, Jenkins and Ricklefs 2011) are considerably enhanced by ecological biogeography, providing a more complete view of the forces structuring odonate diversity. This chapter reviews current knowledge of the distribution of odonates globally, and also considers work in a number of active research areas in odonate biogeography, including the influence of climate on changing distribution, life-history attributes, adaptation to changing landscapes, and the use of biogeographical methods in odonate conservation. It concludes that, while recent decades have seen much important work, much remains to be done to understand global odonate distributions, and to safeguard odonate diversity.

This chapter examines the current state of phylogeographic research in the order Odonata and reviews empirical contributions at both a global scale and within the main biogeographical regions (Holarctic, Tropical, Indo-Malayan, Australasian, and Oceanic-Pacific). It highlights the fundamental processes responsible for the origin and maintenance of odonate biodiversity. In addition, it discusses the current opportunities and limitations of performing phylogeographic studies considering new advances in data acquisition (e.g. high throughput sequencing) and analytical approaches of key biological fields (e.g. landscape genetics, niche ecology modeling, phylogenetic community) to lay a foundation for future research. The last decade has been an exciting time in phylogeography, and much work remains to be done to understand the evolutionary history of odonate distributions.

As in many other lineages, the dragonflies, or anisoptera (Insecta: Odonata), contain a myriad of life history and diversification patterns. Two families within anisoptera highlight the diversity of patterns in this sub-order. As the most recently derived anisopteran family, some species of Libellulidae typically live fewer than two years (although generation times vary across the group), and some clades are thought to be tolerant of poor water quality. The family comprises 1500 known species. In contrast, an earlier diverging family of anisoptera, the Petaluridae, live longer than five years, and are some of the only semi-terrestrial dragonflies. Petaluridae contains only 11 extant species, all of which specialize in fen habitats. Here we sequence the genomes of two dragonflies, the petalurid, Uropetala carovei , and the libellulid, Pachydiplax longipennis . By comparing these genomes to previously published genomes of Petaluridae and Libellulidae we identify potential biological functions related to significantly expanding gene families in both lineages. Notably, the Libellulidae have significant expansions of gene families related to the maintenance of homeostasis and gene expression, which we hypothesize could play a role in the ability of the Libellulidae to thrive in low-quality water bodies. The Petaluridae have significantly expanded gene families related to perception of taste and negative regulation of apoptosis, which can plausibly be tied to their semi-terrestrial lifestyle and longevity. Additionally, we demonstrate that Odonata have relatively high rates of gene turnover, and that the difference in gene turnover between Libellulidae and Petaluridae are comparable.Significance This work is the first major analysis of the evolution of gene families in the order Odonata, providing future directions for research in this order, and filling in a major taxonomic gap. Furthermore, this is the first work to tie genomic traits to life history and evolutionary patterns in Odonata. The patterns of gene family evolution identified, and the traits they are linked to, will be of broad interest to evolutionary biologists.### Competing Interest StatementThe authors have declared no competing interest.

We present a chromosome-length genome assembly and annotation of the Black Petaltail dragonfly (Tanypteryx hageni). This habitat specialist diverged from its sister species over 70 million years ago, and separated from the most closely related Odonata with a reference genome 150 million years ago. Using PacBio HiFi reads and Hi-C data for scaffolding we produce one of the most high-quality Odonata genomes to date. A scaffold N50 of 206.6 Mb and a single copy BUSCO score of 96.2% indicate high contiguity and completeness.