Male pheromone polymorphism and reproductive isolation in populations of Drosophila simulans

Abstract

The dominant cuticular hydrocarbons (HC) in Drosophila simulans are 7-tricosene (7-T) and 7-pentacosene (7-P). The 7-T is the major HC in East Africa and in other continents. In West Africa, D. simulans is very rare and displays 7-P as the major compound. We studied three D. simulans strains from Egypt (Eg), Sao-Tome (ST), and Cameroon (Cam), with 7-T, intermediary or 7-P phenotypes. HC profiles of ST and Cam female differed slightly from corresponding male profiles; females had more 7-T and less 7-P. Varying temperature affected all HCs (even those with 27 and 29 carbons)-not just 7-T and 7-P; there was no clear relationship between HC phenotype and resistance to desiccation. We report reproductive isolation between Eg and ST and Eg and Cam (but not between ST and Cam), which is due to Eg and Cam female preferences for their own males. In conclusion, our findings do support divergence of D. simulans populations from West Africa for both pheromonal profile and mating preference.

Interaction between temperature and male pheromone in sexual isolation in Drosophila melanogaster

“…This importance is confirmed by our results on Com selected lines; selection for pheromone phenotypes led to partial sexual isolation between Com7T and Com7P flies in only 14 generations. The role of male pheromone differences in sexual isolation has also been shown in the pheromonal races of the closely related species D. simulans (Bontonou et al ., 2012 ) and in most distant species; selection on CHCs in D. serrata has been shown to result in sexual isolation in only nine generations (Higgie et al ., 2000 ). This confirms that pheromones are important factors that can lead to rapid sexual isolation in Drosophila .…”

Sexual Communication in the Drosophila Genus

“…Although populations from different locations have clear-cut CHC phenotypes (either 7-T or 7-P), we found a population from the Comoro Islands, in which males fell on a continuum ranging from low to high levels of 7-T. After 15 generations of selection for CHC profile, the “7-T” and “7-P” selected lines showed reproductive isolation [ 95 ]. Likewise, other experiments conducted on 7-T and 7-P strains of D. simulans show reproductive isolation between strains with different CHC phenotype (7-T or 7-P) suggesting that male CHCs could contribute to sex isolation in this species [ 98 ]. Several factors involved in courtship behavior or female receptivity could also contribute to sexual isolation.…”

Hydrocarbon Patterns and Mating Behaviour in Populations of Drosophila yakuba

“…The oven temperature started at 180 °C then ramped at 3 °C/min to 300 °C, for a total run of 40 min. The flame ionization detector was set at 260 °C [ 12 ]. CHCs were identified by GC-MS and then by their retention times.…”

“…This CHC polymorphism is involved in reproductive isolation [ 9 ]. Male pheromones also play a role in reproductive isolation between D. santomea and D. yakuba [ 10 ], and between populations of D. melanogaster [ 11 ] and D. simulans [ 12 ].…”