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Abstract Odonata is a midsized insect order (~6420 species) containing 3 suborders: Anisoptera (dragonflies, 3,120 species), Zygoptera (damselflies, ~3,297 species), and the intermediate Anisozygoptera (~3 species). In this review of the suborder Zygoptera, we provide a brief overview of their biology, ecology, and natural history. We also review the current state of their systematics and phylogenetics, highlighting remaining higher-level classification (eg family, superfamily) issues to address. Lastly, we will emphasize areas that are still in need of exploration which would greatly improve our understanding of the group. 

Abstract 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. 

Abstract Using recently published chromosome‐length genome assemblies of two damselfly species,Ischnura elegansandPlatycnemis pennipes, and two dragonfly species,Pantala flavescensandTanypteryx 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 inP. flavescenswas lost through fusion with autosomes. 

Abstract 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. 

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. 

The advent of third generation sequencing technologies has led to a boom of high-quality, chromosome level genome assemblies of Odonata, but to date, these have not been widely used to estimate the demographic history of the sequenced species through time. Yet, an understanding of how lineages have responded to past changes in the climate is useful in predicting their response to current and future changes in the climate. Here, we utilized the pairwise sequential markovian coalescent (PSMC) to estimate the demographic histories of Sympetrum striolatum, Ischnura elegans, and Hetaerina americana, three Odonata for which chromosome-length genome assemblies are available. Ischnura elegans showed a sharp decline in effective population size around the onset of the Pleistocene ice ages, while both S. striolatum and H. americana showed more recent declines. All three species have had relatively stable population sizes over the last one hundred thousand years. Although it is important to remain cautious when determining the conservation status of species, the coalescent models did not show any reason for major concern in any of the three species tested. The model for I. elegans confirmed prior research suggesting that population sizes of I. elegans will increase as temperatures rise. 

More than 1.2 million distribution records were used to create species distribution models for 402 Palaearctic species of dragonflies and damselflies. On the basis of these diversity maps of total, lentic and lotic diversity for the whole of the Palaearctic (excluding China and the Himalayan region) are presented. These maps show a clear pattern of decreasing diversity longitudinally, with species numbers dropping in the eastern half of Europe and remaining low throughout a large part of Russia, then increasing again towards Russia’s Far East and Korea. There are clear differences in diversity patterns of lentic and lotic species, with lentic species being dominant in colder and more arid areas. Areas with a high diversity of species assessed as threatened on the IUCN red list are largely restricted to the Mediterranean, Southwest Asia, and Japan, with clear hotspots found in the Levant and the southern half of Japan. The diversity at species, generic, and family level is higher in the south of Japan than in areas at a similar latitude in the western Mediterranean. This is likely to be the result of the more humid climate of Japan resulting in a higher diversity of freshwater habitats and the stronger impact of the glacial periods in the Western Palaearctic in combination with the Sahara, preventing tropical African lineages dispersing northwards.