IMPACTS OF HEAT WAVES ON ORCHARD BEE FITNESS AND DEVELOPMENT: A COMPARATIVE STUDY OF THREE WESTERN POPULATIONS

My overall goal is to quantify the impacts of heatwaves on O. lignaria during two key stages in early development, across three western populations, at two levels (organismal and molecular):Objective 1: Determine the impacts of heatwaves on organismal responses. I will source bees from three populations (CA, WA, UT) across the range of O. lignaria propinqua. I will then expose bees to heatwaves during larval and pupal life stages and measure differences in developmental rates, stage-specific survival, and adult ovary development and morphological traits. This will allow me to comprehensively test when and where sensitivity and resilience to heat exposure exist in the species and explore ultimate consequences for direct (survival) and indirect (ovarian development) components of fitness.Objective 2: Identify molecular mechanisms associated with heat stress and resilience during development from different populations. I will next use gene expression data generated from bees in Obj. 1 to test the hypothesis that particular life stages and populations are more resilient to heat because they possess mechanisms that support developmental stability in the face of thermal stress. This hypothesis is predicated on a wealth of studies in other animal systems but has never been tested in solitary bees. This analysis will likely also yield novel candidate genes for thermal resilience in bees.