Submitted to: Journal of Insect Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/24/2008
Publication Date: 1/1/2009
Citation: Aluja, M., Ordano, M., Teal, P.E., Sivinski, J.M., Garcia-Medel, D., Anzures-Dadda, A. 2009. Larval feeding substrate and species significantly influence the effect of juvenile hormone analog on sexual development/performance in four tropical tephritid flies. Journal of Insect Physiology. 55:231-242. Interpretive Summary: Pest fruit flies are often control through sterile male releases (SIT), but increases in mass-rearing efficacy and male sexual competitiveness lower costs and increase efficacy. Ingestion of juvenile hormone (JH) is a means of accelerating maturation in certain fruit flies so that they are ready sooner for release. At the same time JH increases male sexual success in some species. Scientists at the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida in collaboration with colleagues at the Instituto de Ecologia (Xalapa, Vercruz Mexico) exposed four potentially invasive fruit species to JH in their adult food. Flies in only one species matured sooner after eating JH and that was only if they had developed as larvae in a certain type of fruit. The information that JH effects might depend on larval food has implications for the creation of diets for mass-rearing and will be pursued to improve SIT efficacy.
Technical Abstract: The juvenile hormone analog methoprene reduces the amount of time it takes laboratory-reared Anastrepha suspensa (Caribbean fruit fly) males to reach sexual maturity by almost half. Here, we examined if methoprene exerted a similar effect on four other species of Anastrepha (A. ludens, A. obliqua, A. serpentina and A. striata) reared on natural hosts and exhibiting contrasting life history strategies. In the case of A. ludens we worked with two populations that stemmed from Casimiroa greggii (ancestral host, larvae feed on seeds) and Citrus paradisi (exotic host, larvae feed on pulp). In multiple species comparisons, the effect of methoprene on first appearance of male calling behavior was only apparent in the case of A. ludens, and then only in flies stemming from C. greggii. The opposite effect was found for the number of days elapsed until the first female oviposited, in which case females from C. paradisi started to lay eggs almost one day earlier than those stemming from C. greggii. Additionally, males of A. ludens males stemming from C. paradisi (independent of treatment) called and mated almost twice as often as did males stemming from C. greggii. There were significant host and host by treatment interactions with respect to egg clutch size for A. ludens. Females stemming from C. paradisi laid significantly more eggs per clutch and total number of eggs than females stemming from C. greggii. In the multiple species comparison, treatment and treatment by species interaction effects were detected with respect to mean clutch size. Finally, eclosion from eggs varied between species with A. serpentina having the lowest hatch. We center our discussion on a larval-food hypothesis which we develop based on the differential effect of methoprene observed in A. ludens depending on host origin and also interpret our results in light of the life history differences exhibited by the different species we compared.