Conceptual framework and rationale

The sterile insect technique (SIT) has been shown to be an effective and sustainable genetic approach to control populations of selected major pest insects, when part of area-wide integrated pest management (AW-IPM) programmes. The technique introduces genetic sterility in females of the target population in the field following their mating with released sterile males. This process results in population reduction or elimination via embryo lethality caused by dominant lethal mutations induced in sperm of the released males. In the past, several field trials have been carried out for mosquitoes with varying degrees of success. New technology and experience gained with other species of insect pests has encouraged a reassessment of the use of the sterility principle as part of integrated control of malaria vectors. Significant technical and logistic hurdles will need to be overcome to develop the technology and make it effective to suppress selected vector populations, and its application will probably be limited to specific ecological situations. Using sterile males to control mosquito vector populations can only be effective as part of an AW-IPM programme. The area-wide concept entails the targeting of the total mosquito population within a defined area. It requires, therefore, a thorough understanding of the target pest population biology especially as regards mating behaviour, population dynamics, dispersal and level of reproductive isolation. The key challenges for success are: 1) devising methods to monitor vector populations and measuring competitiveness of sterile males in the field, 2) designing mass rearing, sterilization and release strategies that maintain competitiveness of the sterile male mosquitoes, 3) developing methods to separate sexes in order to release only male mosquitoes and 4) adapting suppression measures and release rates to take into account the high reproductive rate of mosquitoes. Finally, success in area-wide implementation in the field can only be achieved if close attention is paid to political, socio-economic and environmental sensitivities and an efficient management organization is established taking into account the interests of all potential stakeholders of an AW-IPM programme

Methoprene and protein supplements accelerate reproductive development and improve mating success of male tephritid flies

We have been studying the behavioural and physiological mechanisms associated with coordination of reproductive maturity and sex pheromone communication in male tephritid flies in order to develop methods for acceleration of reproductive maturity among sterilized males. Our studies revealed that exposure to the juvenile hormone analogue methoprene can accelerate the rate of sexual maturity in some but not all tephritid species tested. Additionally, we have determined that incorporation of protein hydrolysate into the adult diet improves sexual performance of sterile males. Coupling a diet enriched with protein hydrolysate for adult food and application of methoprene to adult males or pupae was found to advance significantly the age at which males of a number of species of flies from the genus Anastrepha and Bactrocera cucurbitae (Coquillet) become sexually mature and improve reproductive success of the males. These results have led to the development of a novel strategy to accelerate the reproductive development and increased competitiveness of mass-reared fruit flies for use in the sterile insect technique by incorporating methoprene treatment and protein hydrolysate diets into protocols for fruit fly emergence and release facilities. The following reviews research conducted to develop the system and our suggestions for use in improving efficacy of mating by sterile males destined for release in programmes to control some species of tephritid flies using the sterile insect technique.Fil: Teal, P. E. A.. United States Department of Agriculture. Agricultural Research Service; ArgentinaFil: Pereira, R.. Joint FAO/IAEA. Division of Nuclear Techniques in Food and Agriculture; AustriaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Haq, I.. Joint FAO/IAEA. Division of Nuclear Techniques in Food and Agriculture; AustriaFil: Gomez Simuta, Y.. Programa Moscamed. Departamento de Desarrollo de Métodos; MéxicoFil: Robinson, A. S.. Joint FAO/IAEA. Division of Nuclear Techniques in Food and Agriculture; AustriaFil: Hendrichs, J.. Joint FAO/IAEA. Division of Nuclear Techniques in Food and Agriculture; Austri