Inherited sterility in insects  The inherited sterility in insects is induced by substerilizing doses of ionizing radiation. When partially sterile males mate with wild females, the radiation-induced deleterious effects are inherited by the F1 generation. As a result, egg hatch is reduced and the resulting offspring are both highly sterile and predominately male. Compared with the high radiation required to achieve full sterility in Lepidoptera, the lower dose of radiation used to induce F1 sterility increases the quality and competitiveness of the released insects as measured by improved dispersal after release, increased mating ability, and superior sperm competition. Area-wide integrated pest management programmes using the sterile insect technique (SIT) as a component have been successful against a number of pest flies or Diptera such as the New World screwworm, "Cochliomyia hominivorax", various species of tephritidae fruit flies and against tsetse flies (Glossinidae). However, most moths or lepidopterans are more resistant to radiation than dipterans, and as a consequence, the higher dose of radiation required to completely sterilize lepidopterans reduces their performance in the field. One approach to circumvent the negative effects associated with the high radio-resistance of Lepidoptera pests has been the use of inherited sterility or F1 sterility, first documented in studies on the codling moth ("Cydia pomonella"). Inherited sterility has also been documented in the Hemiptera order. The silk worm "Bombyx mori" (Lepidoptera: Bombycidae) was the first insect in which inherited sterility was reported. Then inherited sterility was reported in the greater wax moth "Galleria mellonella" (Lepidoptera:Pyralidae), in the codling moth "Cydia pomonella" (Lepidoptera: Tortricidae), in the large milkweed bug "Oncopeltus fasciatus" (Hemiptera: Lygaeidae), in "Gonocerus acuteangulatus" (Hemiptera: Coreida), in "Rhodnius prolixus" (Hemiptera: Reduviidae), and in the Two-spotted spider mite "Tetranychus urticae" (Acari: Tetranychidae). The mechanisms by which mutations cause lethality in Diptera in the developing zygote are well documented.