Data from: Premating isolation is determined by larval rearing substrates in cactophilic Drosophila mojavensis. X. Age-specific dynamics of adult epicuticular hyrdocarbon expression in response to different host plants

Analysis of sexual selection and sexual isolation in Drosophila mojavensis
and its relatives has revealed a pervasive role of rearing substrates on
adult courtship behavior when flies were reared on fermenting cactus in
preadult stages. Here, we assessed expression of contact pheromones
comprised of epicuticular hydrocarbons (CHCs) from eclosion to 28 days of
age in adults from two populations reared on fermenting tissues of two
host cacti over the entire life cycle. Flies were never exposed to
laboratory food and showed significant reductions in average CHC amounts
consistent with CHCs of wild-caught flies. Overall, total hydrocarbon
amounts increased from eclosion to 14–18 days, well past age at sexual
maturity, and then declined in older flies. Most flies did not survive
past 4 weeks. Baja California and mainland populations showed
significantly different age-specific CHC profiles where Baja adults showed
far less age-specific changes in CHC expression. Adults from populations
reared on the host cactus typically used in nature expressed more CHCs
than on the alternate host. MANCOVA with age as the covariate for the
first six CHC principal components showed extensive differences in CHC
composition due to age, population, cactus, sex, and age × population, age
× sex, and age × cactus interactions. Thus, understanding variation in CHC
composition as adult D. mojavensis age requires information about
population and host plant differences, with potential influences on
patterns of mate choice, sexual selection, and sexual isolation, and
ultimately how these pheromones are expressed in natural populations.
Studies of drosophilid aging in the wild are badly needed.