Biology subjects

Tolman, E. R.

Publications and source records attributed to Tolman, E. R..

7 recordsLinked to original sources

bioRxiv2026

Sex in the City: Reproductive Behaviors of Dragonflies across an Urban Landscape

Anthropogenic cityscapes provide complex habitats that influence animal communication and movement patterns, which are generally understudied in aquatic and semi-aquatic organisms. Community science, referring to public participation in scientific research, is an important tool for recording occurrence records and behavioral observations of understudied urban species. Boise, Idaho (USA), one of the fastest-growing cities in North America, has a long-established community science program for documenting occurrences of the semi-aquatic insect order Odonata (dragonflies and damselflies), making the city an ideal study system for comparing behavioral observations from community science with observations recorded using AI driven iNaturalist. In this study, we test the accuracy of iNaturalist observations and volunteer surveys to characterize dragonfly reproductive behaviors (tandem flight and tandem perching, oviposition, and mating) in the city, and use these observations to determine which dragonflies are using the urban landscape as reproductive habitat. The total numbers of species observations by volunteers and on iNaturalist in Boise were strongly correlated, while reproductive observations showed a strong observational threshold, as reproductive behaviors were rarely identified in less-observed species. iNaturalist tended to underrepresent total occurrences of ''flyer'' species, which rarely perch, while volunteer surveys underrepresented occurrences and reproductive behaviors of a more cyclical species that did not appear to be abundant in the field season in which this study was conducted. Our findings suggest that Boise provides suitable breeding habitat for both migratory and resident dragonflies. Species distribution models of three migratory and three putatively migratory species further demonstrate that these species would be expected in southwestern Idaho regardless of the presence of a city, and have persisted through urban development. This research demonstrates the value of community science in conducting basic research on understudied urban-dwelling species, although findings must be considered alongside potential biases.

ecology↗

bioRxiv2026

Comparative genome analyses suggest a common blueprint for obligate endoparasitism in Strepsiptera

The twisted-wing parasites (order Strepsiptera) are well-known for their unusual life histories as obligate endoparasites of a wide variety of other insect orders. Here, we present the first high-quality genome assembly of a leafhopper-parasitizing strepsipteran species. We sequenced the genome of Elenchus koebelei using PacBio HiFi technology, yielding a primary assembly of 63.7Mb in 96 contigs, with an N50 of 1.60Mb and a BUSCO completeness score of 82.3%. In total, we recovered 8,167 protein-coding gene annotations, and 34.2% of the genome annotated as repeats. For the first time, we compare the genome content of three strepsipteran species and find that they are remarkably consistent in broad structure, with approximately 600 insect universal single-copy orthologs that appear to be completely missing from the order. These similarities imply a conserved genomic blueprint for strepsipteran parasitic strategy and/or differences that must be investigated at the post-translational level.

genomics↗

bioRxiv2025

GhostParser: A highly scalable phylogenomic approach for the identification of ghost introgression

A growing body of empirical research shows that interspecific gene flow is a widespread biological force that shapes evolutionary histories across the Tree of Life. Computational approaches designed to detect introgression either employ full likelihood, including Bayesian, frameworks to directly estimate phylogenetic networks or utilize summary statistics derived directly from locus sequence alignments or estimated gene trees to map gene flow events onto the species tree. Many current methods currently have major shortcomings. The computationally scalable summary statistics and pseudo-likelihood-based techniques may provide erroneous results in the presence of so-called "ghost" introgression and rate variation between lineages. On the other hand, full likelihood methods are more accurate, but are not computationally tractable for large phylogenomic datasets. Here, we develop a novel summary statistic, based on tree heights of different gene tree topologies to reliably distinguish between sampled and ghost introgression events. We implemented this approach in the publicly accessible bioinformatic pipeline "GhostParser". We demonstrate that GhostParser can accurately distinguish between scenarios of sampled and ghost introgression, even in the presence of rate variation between lineages. Our methodology generally concurs in accuracy with the full likelihood software Bayesian Phylogenetics and Phylogeography (BPP) on empirical datasets, and outperforms BPP in our simulation conditions, both in a small fraction of the computational time. We show that GhostParser is a scalable tool for the identification of different introgression patterns in phylogenomic datasets.

bioinformatics↗

bioRxiv2024

The Blueprint for Survival: The Blue Dasher Dragonfly as a Model for Urban Adaptation

Human 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. Using 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. Given the shared barriers to colonizing an urban habitat, we expect that many of the adaptations we have identified in P. longipennis can be used for predicting what animals might succeed in urban habitats more generally.

evolutionary biology↗

bioRxiv2024

Environmental DNA vs. Community Science: Strengths and Limitations for Urban Odonata Surveys

The study of insect decline remains a major frontier in insect biodiversity and conservation. Despite growing concern about accelerating rates of insect decline 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 within an urban system 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 damage. 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, in our study system, eDNA and community science are highly complementary of each other. In cases where only one method is employed for a monitoring or conservation project, care should be given to account for the biases of each approach.

ecology↗

bioRxiv2024

Elevational and Oceanic Barriers Shape the Distribution, Dispersal and Diversity of Aotearoa's Kapokapowai (Uropetala) Dragonflies

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 sub-genomic 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 K[a] Tiritiri-o-te-Moana (the Southern Alps) is not impervious but it significantly restricts gene flow between aforementioned species. Our data support the hypothesis of an active colonization of K[a] 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.

evolutionary biology↗

bioRxiv2023

Newly Sequenced Genomes Reveal Patterns of Gene Family Expansion in select Dragonflies (Odonata: Anisoptera)

Gene family evolution plays a key role in shaping patterns of biodiversity across the tree of life. In Insecta, adaptive gene family turnover has broadly been tied to vision, diet, pesticide resistance, immune response and survival in extreme environments. Patterns of gene family evolution are of particular interest in Odonata (dragonflies and damselflies), which represents the first lineage to fly, and one of the most exceptional groups of predators. Previous work in Odonata found expansions of opsin genes are correlated with the diversification of the herbivorous insects that Odonata prey upon, but general trends in gene family turnover has not been studied in this order. Here, we show that two families of suborder Anisoptera (dragonflies), Libellulidae and Petaluridae, have expanded gene repertoire related to their unique life history and diversification patterns. These results are an important step towards understanding why Libellulidae is, generally, a species rich family of short lived species that are highly tolerant to poor water quality, while Petaluridae is a species poor family of habitat and behavioral specialists. Specifically, Libellulidae share expanded gene families related to immune response, desiccation response, and processing of free radicals, which all potentially enable many Libellulidae to inhabit low quality water bodies. Likewise, Petaluridae show unique patterns of gene turnover in gene families implicated in sensory perception, which could be tied to the unique semi-terrestrial lifestyle of the nymphs of this family. Furthermore, Odonata as a whole has a gene gene turnover rate that is an order of magnitude smaller than other studied insect orders, potentially contributing to the relatively low species diversity in the order Odonata compared to other insects. These results offer important hypotheses for the consideration of evolutionary drivers across Insecta.

evolutionary biology↗