Submitted to: Journal of Insect Physiology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/5/2010
Publication Date: 6/1/2010
Publication URL: http://dx.doi.org/10.1016/j.jinsphys.2010.05.008
Citation: Pereira, R., Sivinski, J.M., Teal, P.E., Brockmann, J. 2010. Enhancing male sexual success in a lekking fly (Ananstrepha suspensa (Diptera: Tephritidae) through a juvenile hormone analog has no effect on adult mortality. Journal of Insect Physiology. 56:1552-1557. Interpretive Summary: Fruit flies attack hundreds of fruits and vegetables and cause trade restrictions wherever they occur. Mass rearing and release of sterile male flies is an important means of their area-wide control, however sterilizing radiation has harmful side effects and renders treated males less sexually competitive than wild rivals. Scientists at the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida found that enriched diets and application of a hormone removed this competitive disadvantage. Males provided with both treatments were much more likely to attract females and better able to defend their mating territories. This increased performance had no cost in terms of longevity. While these treatments will add to rearing costs, the increased efficacy of the sterile flies may result in better control and ultimately lower expenditures.
Technical Abstract: While defending lek-territories, male Anastrepha suspensa (Loew) produce chemical, acoustic and visual courtship signals. In the laboratory and under semi-natural conditions, topical application of the juvenile hormone analog methoprene doubles pheromone production and subsequently doubles sexual success. However, sexual signals and interactions are likely to be physiologically expensive and so result in higher male mortality. Comparison of males kept in isolation for 35 days, but provided daily with a potential mate or a rival male, revealed that both male and female-interactors shortened focal-male lifespan. In addition, focal males were either treated with methoprene or not, then either provided with protein in their sucrose-based diet or not. Protein proved to similarly double sexual success and also resulted in longer male life spans in all of the interactor-categories. However, there was no evidence that methoprene induced hypersexuality resulted in higher rates of mortality: i.e., the longevity of males treated with methoprene did not significantly differ from untreated males in the same interactor/diet catagories. This apparent lack of cost to a presumably sexually-selected signal is unexpected but presents an opportunity to increase the sexual competence of sterile flies with few consequences to their survival following mass-release.