Tetracycline-suppressible female lethality and sterility in the Mexican fruit fly, Anastrepha ludens

The sterile insect technique (SIT) involves the mass release of sterile males to suppress insect pest populations. SIT has been improved for larval pests by the development of strains for female-specific tetracycline-suppressible (Tet-off) embryonic lethal systems for male-only populations. Here we describe the extension of this approach to the Mexican fruit fly, Anastrepha ludens, using a Tet-off driver construct with the Tet-transactivator (tTA) under embryo-specific Anastrepha suspensa serendipity alpha (As-srya) promoter regulation. In the absence of tetracycline, tTA acts upon a Tet-response element linked to the pro-apoptotic cell death gene lethal effector, head involuation defective (hid), from A. ludens (Alhid Ala2) that contains a sex-specific intron splicing cassette, resulting in female-specific expression of the lethal effector. Parental adults double-homozygous for the driver/effector vectors were expected to yield male-only progeny when reared on Tet-free diet, but a complete lack of oviposited eggs resulted for each of the three strains tested. Ovary dissection revealed nonvitellogenic oocytes in all strains that was reversible by feeding females tetracycline for 5 days after eclosion, resulting in male-only adults in one strain. Presumably the sry-alpha promoter exhibits prezygotic maternal expression as well as zygotic embryonic expression in A. ludens, resulting in a Tet-off sterility effect in addition to female-specific lethality.