Premating isolation is determined by larval rearing substrates in cactophilic D rosophila mojavensis . IX. Host plant and population specific epicuticular hydrocarbon expression influences mate choice and sexual selection

• Published in: Journal of evolutionary biology 2013-03, Vol.26 (3), p.562-576
• Main Authors: Havens, J. A., Etges, W. J.
• Format: Article
• Language: English
• ISSN: 1010-061X; 1420-9101
• DOI: 10.1111/jeb.12073

Sexual signals in cactophilic D rosophila mojavensis include cuticular hydrocarbons ( CHC s), contact pheromones that mediate female discrimination of males during courtship. CHC s, along with male courtship songs, cause premating isolation between diverged populations, and are influenced by genotype × environment interactions caused by different host cacti. CHC profiles of mated and unmated adult flies from a B aja C alifornia and a mainland M exico population of D . mojavensis reared on two host cacti were assayed to test the hypothesis that male CHC s mediate within‐population female discrimination of males. In multiple choice courtship trials, mated and unmated males differed in CHC profiles, indicating that females prefer males with particular blends of CHC s. Mated and unmated females significantly differed in CHC profiles as well. Adults in the choice trials had CHC profiles that were significantly different from those in pair‐mated adults from no‐choice trials revealing an influence of sexual selection. Females preferred different male CHC blends in each population, but the influence of host cactus on CHC variation was significant only in the mainland population indicating population‐specific plasticity in CHC s. Different groups of CHC s mediated female choice‐based sexual selection in each population suggesting that geographical and ecological divergence has the potential to promote divergence in mate communication systems.