Meeting Abstract
16.1 Saturday, Jan. 4 10:15 Do clines in Drosophila flight morphology result from adaptive environment-phenotype matching? RUSSEY, WA*; FRANKINO, WA; Univ. of Houston; Univ. of Houston warussey@gmail.com
Drosophila exhibit convergent genetically-based clines and phenotypic plasticity in absolute and relative wing size; relative to warm environments, cooler environments produce large flies with disproportionately large wings. Although this pattern has been documented for many insect species on several continents, the reasons for the pattern remains unknown. The leading hypothesis is that selection on flight performance across thermal environments favors the observed patterns in morphology, although data addressing this hypothesis are scant and the importance of phenotypic plasticity in producing and maintaining these patterns remains unknown. Discussed here is a two-part study to (I) impose natural selection on flight performance in warm and cool environments to create experimentally derived populations of flies possessing morphology suited to flight at each temperature, and (II) assess the adaptive nature of the derived morphologies in ecologically relevant flight assays. Two experimental evolution studies were performed. In the first, warm and cool-selected populations were both reared at an intermediate temperature, removing effects of thermally-induced phenotypic plasticity. In the second experiment, warm and cool-flight selected lines were reared such that temperature of rearing was the same as the temperature of adult flight, providing a reliable cue during development. The experiments discussed here rigorously test the hypothesis that selection on ecological performance has produced a biogeographic morphological pattern frequently cited as one of the most compelling cases of adaptation known. In addition, the proposed work will offer general understanding into how developmentally and functionally integrated suites of traits might change rapidly under different thermal regimes, and quantify the importance of plasticity in this system.
