Influence of Wolbachia on thermal tolerance of South American Drosophila melanogaster populations

• Grant number: 24/05951-8
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: August 01, 2024
• End date: January 31, 2025
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Rodrigo Cogni
• Grantee: Rafael Viana Amaral
• Supervisor: Brandon S Cooper
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: University of Montana (UM), United States
• Associated to the scholarship: 23/00408-1 - The importance of phenotypic plasticity on clinal adaptation of South American D. melanogaster populations, BP.MS

Abstract

Latitudinal clines are often interpreted as evidence for climate adaptation, which gets stronger when they are linked to thermal tolerance phenotypes. Wolbachia is a maternally transmitted endosymbiont found in more than 65% insect species. Infection by Wolbachia is found in a latitudinal cline for natural populations of the fly Drosophila melanogaster, where temperate climates correlate to lower infection frequency. Given cold temperature hinders Wolbachia maternal transmission, we expect Wolbachia to influence phenotypes related to cold tolerance of its hosts. My master thesis work has described for a latitudinal cline on cold tolerance for South American populations of D. melanogaster, but a counterintuitive effect of phenotypic plasticity, as higher developmental temperature drives more cold tolerance. As we also confirmed a cline on Wolbachia infection frequency in South America, we considered it relevant to complement my thesis with an investigation of the effect the endosymbiont may have on the plasticity of our sampled populations. In collaboration with Cooper's laboratory (University of Montana), we will measure how Wolbachia affects chill coma recovery time and temperature preference on isofemale lines from extremes of the South American cline, and also assess how Wolbachia maternal transmission on the same lines changes with temperature variation. We expect the new data on the interaction effects to complement the explanation for how variation in cold tolerance is linked to climate adaptation in South American D. melanogaster populations.