Effects of natural temperature variation on male perception of female scents in Drosophila melanogaster

Ecological factors can shape the processes and mechanisms underlying mate attraction. Growing evidence shows that temperature influences the biosynthesis, transmission and perception of semiochemicals involved in the transfer of information during reproduction (e.g. pheromones). However, little is known about how natural variation in temperature may affect chemically mediated mate attraction. In this study, whether and how temperature variation influences male attraction to female scents was examined in flies from a wild Drosophila melanogaster population. Chemosensory trials were conducted at a common temperature arena of 24 °C giving males a choice between a nonscented swab (control) versus a swab impregnated with female scents. Female scents were collected by allowing females to interact with cotton swabs for 6 h prior to tests at 20 °C or 28 °C, while control swabs were maintained at the same temperatures but without any females. Results indicated that males were only attracted to swabs bearing female scents maintained at 20 °C. In addition, chromatography–mass spectrometry was used to investigate whether female cuticular hydrocarbons, which are key molecules in mate attraction, changed depending on temperature (20 °C, 24 °C or 28 °C) and exposure time (6 or 12 h). Temperature and treatment duration showed a strong influence on female cuticular hydrocarbons. Furthermore, previously identified sexual pheromones with a role in mate attraction were not affected in a way that is consistent with the results from chemosensory trials. The results indicate that high temperatures may impair mate attraction, and this interaction may be partially mediated by the effects of temperature on female cuticular hydrocarbons. We discuss how these constraints on chemically mediated mate attraction may affect sexual selection processes and reproductive trade-offs. • Temperature affects male attraction to female scents in wild D. melanogaster. • Males were attracted when females were exposed at 20 °C but not at 28 °C. • Female cuticular hydrocarbon changed with temperature and exposure time. • No correlation was found between sexual pheromones and changes in male attraction. • High temperatures may hinder chemically mediated mate attraction.