Manipulating courtship opportunities made Drosophila pseudo. sing longer, faster, and fly and move faster

Mate choice intensifies motor signalling in Drosophila. Allan Debelle et al. Animal Behaviour, Volume 133, November 2017, Pages 169–187. https://doi.org/10.1016/j.anbehav.2017.09.014

Highlights
•    We experimentally increased or decreased sexual selection in Drosophila populations.
•    We perform an in-depth analysis of the response of a motor signal (pulse rate).
•    Polyandrous males sing at a faster rate and do so for longer than monogamous males.
•    Fast song rates are associated with overall increased male motor performance.
•    Increasing the opportunity for mate choice increased male motor performance.

Mate choice has the potential to act on the evolution of motor performance via its direct influence on motor sexual signals. However, studies demonstrating this are rare. Here, we performed an in-depth analysis of Drosophila pseudoobscura courtship song rate, a motor signal under mate choice in this species, and analysed the response of this signal to sexual selection manipulation using experimental evolution. We show that manipulating the opportunity for sexual selection led to changes in song production rate and singing endurance, with males from the polyandrous populations producing faster song rates over longer time periods than males from monogamous populations. We also show that song rate was correlated with estimates of overall courtship vigour. Our results suggest that the action of mate choice on a motor signal has affected male motor performance displayed during courtship. We consider potential selective benefits associated with changes in motor performance, including condition-dependent signalling, and discuss the implications of these results for the study of motor signals under sexual selection.

Keywords: courtship song; Drosophila pseudoobscura; experimental evolution; interpulse interval; mate choice; motor performance; sexual selection

My commentary: Manipulating courtship opportunities made Drosophila pseudo. sing longer, faster, and fly and move faster. We are not so distant...