Is the Grass Always Greener: The response of a Neotropical passerine to Key Environmental Factors

Background/Question/Methods

Species across the globe are experiencing unprecedented rates of change to their environmental conditions. How these species are responding is a major question in ecology and evolutionary biology today. High-throughput sequencing advances allow us to directly examine changes to the genome as a result of climatic variables. We asked how genetic markers vary across the landscape in a Neotropical migrant, the Black-throated Blue Warbler (Setophaga caerulescens). Then, we used existing variation of climate variables across that landscape to find regions of the genome highly associated with climate variables. We conducted whole genome sequencing on 200 individuals from 12 populations and mapped genetic variation across the landscape using a gradient forest. Then we ran a genotype by environment analysis to determine genetic variation that is best explained by environmental variation and which environmental factors are most closely associated with genetic variation.

Results/Conclusions

We expect to find regions of the genome highly associated with precipitation, given that this is a factor that contributes directly to the density of caterpillars, a major food source of the Black-throated Blue Warbler. Precipitation is also a factor that has decreased in Southern populations and increased in Northeastern populations and has been linked to reproductive success in this species. These results are key to our follow-up work, where we will map the changes of these regions across 100 years across the range of this species.