Sexual selection on multiple female ornaments in dance flies

Citation

Murray RL, Wheeler J, Gwynne DT & Bussière LF (2018) Sexual selection on multiple female ornaments in dance flies. Proceedings of the Royal Society B: Biological Sciences, 285 (1887), Art. No.: 20181525. https://doi.org/10.1098/rspb.2018.1525

Abstract
Sex-specific ornaments typically occur in males, but they can also develop in females. While there are several models concerning the evolution of male-specific ornaments, it is not clear how, or under what circumstances, those models apply to female-specific ornament evolution. Here, we present a manipulative field experiment that explores the theoretical ‘trait space’ of multiple female-specific ornaments to study how these unusual traits evolved. We measured the attractiveness of two female-specific ornaments (pinnate leg scales and inflatable abdominal sacs) in the dance fly Rhamphomyia longicauda in a wild mating swarm. We found significant directional preferences for larger ornaments of both types; however, variation in one of the ornaments (abdominal sacs) was almost three times more effective at improving attractiveness. The abdominal ornament was consistently effective in increasing attractiveness to males regardless of leg ornament expression, while leg ornament size was only effective if abdominal ornaments were very small. These results are consistent with predictions from a sexual conflict model of ornament expression in supporting the probable role of deception in the evolution of female-specific ornaments among dance flies. Sexual conflict can be an important force in generating elaborate sex-specific ornaments in females as well as males.

Keywords
General Biochemistry, Genetics and Molecular Biology; General Immunology and Microbiology; General Agricultural and Biological Sciences; General Environmental Science; General Medicine

Journal
Proceedings of the Royal Society B: Biological Sciences: Volume 285, Issue 1887

• Accepted manuscript