JUVENILE HORMONE: ACTION IN REGULATION OF SEXUAL MATURITY IN CARIBBEAN FRUIT FLIES AND POTENTIAL USE IN IMPROVING EFFICACY OF STERILE INSECT CONTROL TECHNIQUE FOR TEPHRITID FRUIT FLIES

Authors: Teal, Peter; GOMEZ-SIMUTA, YEUDIEL - MEXICO MEDFLY PROGRAM

Submitted to: International Organization Biological Control/West Palearctic Reg. Section
Publication Type: Proceedings
Publication Acceptance Date: 1/17/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: Insects, like all other animals, use chemicals called hormones to control growth, development and reproduction. Scientists at the Center for Medical, Agricultural and Veterinary Entomology, USDA, ARS, Gainesville, Florida have discovered that insect juvenile hormone functions to coordinate all aspects of reproductive development and sexual signaling in the Caribbean fruit fly, a major pest of citrus and other crops in the Caribbean basin including Florida. Their work has shown that application of this hormone can accelerate reproductive development and cause males to attract females much better than insects that do not receive juvenile hormone therapy. This discovery has great potential for improving the effectiveness of the Sterile Insect Technique used to control this, and other fruit flies. In the Sterile Insect Technique massive numbers of sterile male flies are released into the wild and when they mate with wild females the females do not lay fertile eggs. The success of the technique relies on producing sterile males that mate effectively with wild females. The use of juvenile hormone therapy to improve sexual prowess of sterile males has the potential to greatly improve mating of sterile males with wild females and thus improve significantly the effectiveness of the Sterile Insect Technique.

Technical Abstract: Tephritid fruit flies, including the Caribbean fruit fly, pose a serious invasive threat to citrus production. These invasive species are quarantine pests and strict monitoring protocols are in place to detect introductions. The Sterile Insect Technique (SIT) is ideally suited to control of Tephritid fruit fly outbreaks and provides an environmentally safe and species specific method to eradicate Tephritid fruit flies of agricultural importance world wide. Control is achieved in SIT by mass release of sterile males who mate with wild females. Females, mated with sterile males, do not produce offspring and rarely mate more than once. Optimization of SIT requires that sterile males compete with wild males for mates. We have discovered that loss of virginity enhances the sexual prowess of young males of the Caribbean fruit fly. After mating for the first time, males release twice as much sex pheromone, and they acquire another mate in less than half the time required by virgins. Additionally, we discovered that hemolymph of mated males contains significantly more juvenile hormone (JH) than that present in hemolymph of virgin males of the same age. Application of JH or the potent mimic methoprene to males on the day of adult eclosion induced precocious release of pheromone and mating by males. Thus, males, treated with JH, mated 4days earlier than control treated males. This discovery has the potential to improve efficacy of the SIT method because incorporating hormone supplement therapy into mass rearing of sterile males will allow for release of sterile males that are more competitive than those currently in use.