Meeting Abstract
Warming global temperatures, barriers to stream flow, and prolonged drought are contributing to rising temperatures in California’s aquatic environments. Organisms in these warming habitats may experience physiological stress differently depending on local adaptation. Dicosmoecus gilvipes, an aquatic caddisfly with a long larval duration, inhabits streams with differing thermal profiles. Using the larvae of D. gilvipes, we investigated the gene expression response to temperature variation in genetically distinct populations from three streams in California, USA. Individuals from each population were exposed to a control treatment, gradual warming mirroring the current stream temperature or a heat shock. We measured normalized expression of nine biomarkers for cellular stress with NanoString technology. We hypothesized that there would be differences in gene expression between treatments in response to thermal stress and between sites due to local adaptation. The treatment significantly affected the expression of five of nine target genes. Those genes, including heat shock proteins, increased their expression with temperature, up to a 14-fold increase at one site. Six of the nine target genes showed significant differences in expression, up to 6-fold, between sites providing some evidence of genetic adaptation to local environmental conditions. All three populations were responsive to thermal stress, though individuals from the warmest site may already experience stress under current conditions that are likely to warm even further with continued warming and drought.
