Thursday, July 12, 2018 - 12:30
Title: Sex differences in size and shape, do they reflect the same biological processes? Insights with Drosophila wings and beetle horns.
Sexual dimorphism is widespread throughout the animal kingdom. While some examples are exaggerated like the mandibles of stag beetles, most is subtle like differences in human facial shape or height. However, one striking commonality for sexually dimorphic traits is that they are often highly condition dependent. In particular, a reduction of nutritional resources during development leads to a marked decrease in the degree of sexual size dimorphism. However, it remains unclear to what degree condition also influences dimorphism for organismal shape, and how this relates both to overall size and to size dimorphism per se.
In this talk I will highlight our work examining the genetic and genomic basis of variation for sexual size and shape dimorphism. I will introduce the Drosophila wing as model system, not only to study the genetic architecture of complex traits, but for the study of sexual differences in morphology. The Drosophila wing is is a target of sexual selection, has extensive natural variation within and between species for size, shape as well as for sexual dimorphism. I will highlight our research demonstrating that sexual size and shape dimorphism are only partially coupled using variation within and among species and through the use of mutational perturbations in Drosophila melanogaster. Furthermore, while nutritional limitation experiments reduce both sexual shape and size dimorphism, it does so in a genotype dependent manner. These results will be discussed in the context of the evolutionary potential of wing shape and size in sexual and non-sexual contexts and how this compares to highly exaggerated structures like the horns of beetles.