Assessment of mating competitiveness of sterile Ceratitis capitata in laboratory and field cage tests in northern Iran

Abstract

AbstractIn recent years, damage by Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) on commercial fruit crops has reached a critical point in Iran. The sterile insect technique is considered the most effective strategy for the area‐wide suppression or eradication of tephritid fruit flies, particularly the medfly. In this study, an area of citrus trees, including 39 field cages in Sari‐Mazandaran province, was used for an experiment to test various irradiation doses and overflowing ratios on male competitiveness‐induced sterility. Treatments 1 and 2 consisted of non‐irradiated females (NF), non‐irradiated males (NM), and irradiated males (IM) which emerged from pupae irradiated with 80 or 100 Gy. The IM:NM:NF ratios per field cage were varied as follows: 0:1:1, 1:0:1, 1:1:1, 3:1:1, 5:1:1, 10:1:1, and 15:1:1. We found that the mating rate of NF copulating with IM was significantly lower than that of NF mated with NM. The numbers of eggs and the percentages of egg hatching were significantly lower in IM × NF than in NM × NF crosses, and no eggs hatched in the 80–130 Gy dose range. The results of Fried's CV (male mating competitiveness value based on egg hatch) ranged from 0.41 to 0.78 at a dose of 80 Gy and from 0.35 to 0.63 at 100 Gy for various mating rates. It can be concluded that IM was fully competitive with NM at the dose range of 80–100 Gy of gamma radiation.