Submitted to: Journal of Applied Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2010
Publication Date: 8/8/2012
Publication URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0418.2010.01534.x/abstract
Citation: Segura, D.F., Utges, M.E., Liendo, M.C., Rodriguez, M.F., Decescovi, F., Vera, M.T., Teal, P.E., Cladera, J.L. 2012. Methoprene treatment reduces the pre-copulatory period in Anastrepha fraterculus (Diptera: Tephritidae) sterile males. Journal of Applied Physiology. DOI: 10.1111/j.1439-0418.2010.01534.x. Interpretive Summary: The South American fruit fly is a quarantine pest of significant importance to a wide variety of orchard and vegetable crops. There is considerable emphasis on developing control programs for this pest using the sterile insect technique in which the wild population is reduced or eradicated by mass release of sterile males which mate with wild females. Offspring from these mating are sterile. One of the more significant costs associated with SIT protocols is the need to hold mass reared adult flies for as many as 7, or more, days prior to release because males require time to become sexually mature. Scientists at the Instituto de Genética “E.A. Favret”, CNIA, INTA Argentina, the Faculty de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina, the Estación Experimental Agroindustrial, Argentina and the Center for Medical Agricultural and Veterinary Entomology, USDA-ARS, Gainesville Florida have been studying how reproductive development can be accelerated in these flies. They have discovered that addition of the hormone mimic, methoprene, and an adult diet containing protein accelerates reproductive development in males of the South American Fruit fly. Using this technique they have produced sterile males that are more fit and which become sexually mature 5 days earlier than males treated in the standard way. This technology has significant importance for reducing cost of the sterile insect technique for this species and improving efficacy of the technique.
Technical Abstract: Anastrepha fraterculus is a major fruit pest in South America. Ongoing studies encourage the implementation of the sterile insect technique (SIT) against this pest. Sexual readiness of sterile males is a key point for SIT. The time required for A. fraterculus males to become sexually mature is unknown but it like other species of Anastrepha it takes several days. A reduction in reproductive development time was achieved in species from this genus after topical applications of juvenile hormone analogues, including methoprene and fenoxycarb. We studied the sexual maturation process in A. fraterculus males, and the effects of methoprene application and irradiation on this process. We found that A. fraterculus males have a long precopulatory period and this process was effectively accelerated after methoprene treatment (2.5µg/µl). Irradiation status did not affect the response of males to the hormonal treatment. Mating duration for methoprene treated males was longer than for mature untreated males, however no qualitative differences were detected in sperm transferred by each type of male. We found no evidence that acetone affected survival of treated males, at least not in a way that reduces the effectiveness of males for SIT. We found dipping pupae in a methoprene solution allowed the males to mature as fast as the topical treatment, but only when acetone was the solvent. We conclude that the time required for A. fraterculus sterile males to become sexually mature could be shortened by the application of methoprene. This will effectively accelerate maturation of males with no detrimental effects on sperm transferred or survival.