Engineering insects for SIT

Full text: SIT has been used very successfully against a range of pest insects, including various tephritid fruit flies, several moths and a small number of livestock pests. However, modern genetics could potentially provide several improvements. These include: improved identification of released individuals; build in sex separation; reduction of the hazard posed by non-irradiated accidental releases from mass-rearing facility. We have demonstrated that the required strains can be constructed in Drosophila melanogaster, a non-pest insect, by introducing a repressible dominant lethal genetic system, a method known as RIDLTM. We will report our progress in translating this technology to tephritids. We have now developed efficient repressible lethal constructs functional in Ceratitis capitata. Transgenic lines carrying these constructs are easily reared in the presence of a dietary additive that suppresses the lethality; in the absence of the repressor adults are long-lived and competitive, yet 98-100% of their progeny die. The transgenic individuals carry a fluorescent genetic marker and so are readily distinguished from the wild type. Combined with the existing tsl strains developed by IAEA researchers, these lines would provide all the improvements to SIT listed above. These constructs contain no medfly-specific components and so should be equally effective in other tephritids. (author)