Impact of gamma radiation doses on sperm competitiveness, fecundity and morphometric characters of peach fruit fly Bactrocera zonata (Saunders) (Diptera: Tephiritidae)

Successful of Sterile Insect Techniques (SIT) depend on ability of sterile male population to compete with normal male for mating with female and lead to a reduction in pest population numbers and sufficiently effective autocidal control. So effects of radiation doses (0, 30, 50, 70 and 90 Gy) on fertility traits and wings morphometric characters for both sexes of peach fruit fly (PFF) Bactrocera zonata were assayed, in addition different levels of over loading irradiated males to normal population of PFF (sex ratio 1:1) were also concerned. Percents of observed and expected egg hatching and daily egg laying, then competiveness values between irradiated and normal females were estimated. Irradiated males, mated with normal females, induced them to reduce egg laying rates less than the case of irradiated females only or both sexes. However, dose of 70 Gy for males and 50 Gy for either females or both sexes will be sufficient to decrease daily egg laying of females. On the other hand, significantly reduction of egg hatching percentages was noticed with doses of 70 Gy for either females or both sexes, and 90 Gy in case of treated males only. Gamma radiation doses have significant effect on angles and wings length of males and wings width of females. Confined males irradiated with 70 or 90 Gy in numbers as four times as normal males number in PFF population caused depleting in egg hatching percents (ranged between 5.07%: 13.55%). Moreover, the last case gave egg hatching percentages close significantly to cases of irradiation both sexes or male only with 90 Gy (4.28 and 5.49%, respectively), that harboured highest competitiveness value of irradiated males.