Triggers of the Postural Display of Courtship in Drosophila persimilis Flies

Mónica Vega Hernández,Caroline Cecile Gabrielle Fabre

doi:10.1007/s10905-017-9641-1

Abstract

D. persimilis courtship shows some flexibility and courting males sometimes perform an elaborate postural display in addition to the standard courtship behaviours shared by most Drosophila species. This postural display includes the acrobatic contortion and tremulation of their abdomen, accompanied by the generation of substrate-borne vibrations, and they proffer a nutritional droplet to the female. Here, we use courtship and choice assays to ask what triggers this display and what advantages males may gain from it during courtship. In pair assays, we found no differences in the courtship duration and copulation success between displaying and non-displaying males. In trio assays, however, the female always mated with the male who performed the display. To investigate what promotes the male display, we varied the level of receptivity of the female and studied the impact of a second male. We found that rejection by the female does not induce the male to display, contrary to what was previously suggested. We present evidence that the male display is in fact promoted by the presence of an attentive and sexually receptive female and the absence of male competition, with the greatest exhibition rate obtained if the courted female is starved. These findings provide valuable information about the social ecology of flies, and how internal and external cues influence sexual behaviours and mate choice.

Highlights

In many animals, courtship behaviours are important traits for reproductive success (Andersson 1994)
We previously reported that courting D. persimilis males exhibited the postural display of courtship (PDC) (2.6 ± 0.7 PDCs per courtship; Supplementary Movie S1) in addition to the Bstandard^ courtship behaviours in only ~ half (47.5%) of the courting pairs (n = 40 courting pairs; Table 1A and (Hernandez, 2016 #110)), in the other half
Given that mated Drosophila females exhibit much more rejection behaviour than virgin females (Bastock and Manning 1955; Connolly and Cook 1973), which we observed in D. persimilis (Fig. 3; 5.35 ± 0.87 ovipositor extrusions per minute; U = 30, P < 0.05), our observations suggest that the PDC is not a response to female rejection, but is less likely to occur when the female displays rejection behaviours

Summary

Introduction

Courtship behaviours are important traits for reproductive success (Andersson 1994). Sexual selection has influenced the complexity of the courtship displays that a variety of animals use to attract a mating partner and advertise their desire to mate [see for example (Pruett-Jones and Pruett-Jones 1990; Frith and Beehler 1998). Darwin implied that this complexity is a consequence of the Bconstantly recurring struggle between the males for the possession of the females^ with constraints that include direct competition between males (intrasexual selection) and the choice of a mate by the females (intersexual selection). This flexibility in the male behaviour was surprising because Drosophila courtship is usually described as being largely stereotyped [see for example (Spieth 1952; Greenspan and Ferveur 2000)] and, to our knowledge, the finding that ~ half of the D. persimilis courting pairs behave differently to the other half had not previously been reported

Methods

Results

Conclusion