Meeting Abstract
A central question in evolutionary biology is: by what mechanisms do organisms adjust to abiotic variation across their geographic range? While individuals can tolerate a wide range of variation, do they use the same mechanisms at different abiotic extremes, and do populations across a species range employ the same strategies or exhibit local adaptation? Bumble bees often have large geographic distributions that include both latitudinal and altitudinal variation and are thus excellent models to study evolutionary responses to spatio-environmental gradients, especially temperature. Using laboratory-reared Bombus vosnesenskii from low and high elevation sites at northern and southern extremes in California and Oregon, we quantified critical thermal limits and differential gene expression to test for population-specific differences relating to conditions across elevation and/or latitude. Gene expression was measured using RNA sequencing. Critical thermal limits were correlated with climate conditions of queen collection locations. Gene expression also exhibited strong population-specific effects in magnitude, identity, and quantity of differentially expressed genes. We examine results in parallel with a large-scale SNP-based population genomic study of local adaptation across the B. vosnesenskii range. The results have implications in the evolution of thermal adaptation, bumble bee biodiversity, and conservation in a changing climate.
