Changes in effective population size of Odonata in response to climate change revealed through genomics


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.

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