The blueprint for survival: the blue dasher dragonfly as a model for urban adaptation.

Background: 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.

Results: 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.

Conclusions: We 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.