Genotype-dependent effects of human disturbance on organismal fitness
Authors: Heidi Johnson; Nicole Riddle
Affiliation: University of Alabama at Birmingham
Keywords: b. population variation; i. lifespan
Human disturbance causes significant changes to home range and movement distance in wild populations. These changes and other behavior modifications often negatively impact body condition and/or fitness. While disturbance in wild populations is well-documented, there is a lack of systematic investigations defining the impact of the disturbance on energetic tradeoff and body composition. To address this need, we will utilize tools developed to study exercise in Drosophila to mimic disturbance. The Treadwheel induces movement in Drosophila through rotation of the enclosures. To sample genetic variation, we are using strains from the Drosophila Genetic Reference Panel (DGRP). The DGRP is a set of inbred strains derived from wildtype genotypes that models naturally occurring population variation. The DGRP strains differ in baseline activity approximately 525-fold for males and 110-fold for females. They also differ in their weight (1.7-fold), and quantitative magnetic resonance analysis revealed significant variation in body composition among the lines. Differences in weight, activity, and body composition is sex- and genotype-dependent. We use this diverse collection of Drosophila strains to probe the consequences of disturbance on movement patterns, body condition, and organismal fitness. We compare the effects of short-term (5 days of daily treatment on the Treadwheel) and long-term (15 days of daily treatment on the Treadwheel) disturbance regimes. Specifically, we investigate how disturbance alters longevity, offspring count, and physical condition and quantify the impact on organismal fitness, in experiments that are in progress. We expect that the impact of long-term disturbance to be more severe than the impact of short-term disturbance. We also expect to find variation in the responses to the disturbance for all outcome measures and that the outcomes are sex- and genotype-dependent.