Life History and Stress Tolerances in Elevation Adapted Populations of Drosophila melanogaster
Authors: Camille Oster; Elizabeth King
Affiliation: University of Missouri
Keywords: Complex traits
In the era of global climate change, not all environments are impacted equally and uniformly. Of ecosystems facing acute changes in climate, high elevation populations have unique constraints on range and adaptation. Researchers have shown evidence of range shift in Drosophila species to higher elevations, but thermoregulative behaviors may do little to avoid climate stressors in small arthropods. We expect adaptive trade-offs between climate stress tolerances and life history, but this intersection deserves further study for populations with distinct adaptations to elevation; here we investigate those complex traits.
We phenotyped life history and stress-tolerance traits in 8 Drosophila melanogaster populations from sub-Sarahan Africa. These lines, collected and inbred by Pool et al, originate from low-elevation Zambia and high-elevation Ethiopia, both with year-round tropical climates. First, we assayed lifespan and weekly measurements of fecundity in cages of ~1000 individuals with a two to one male to female ratio. Second, we measured starvation resistance by placing adults in non-nutritional agar vials. Finally, we phenotyped thermal tolerance using a Pelt-5 temperature controller in a ramping protocol from room temperature to incapacitation. Due to established sex differences in stress tolerances in Drosophila spp., we prioritized female flies in our assays. Here, we show the effects of genotype and population on this suite of traits and use a multivariate approach to show how these different traits relate to one another.