Irradiation of Anastrepha obliqua (Diptera: Tephritidae) Revisited: Optimizing Sterility Induction

Abstract

The effects of irradiation doses increasing from 0 to 100 Gy (1 Gy is energy absorbed in J kg(-1) of irradiated material) on fertility, flight ability, survival, and sterile male mating performance were evaluated for mass-reared Anastrepha obliqua (Macquart). High sterility values (> 98.2%) for irradiated males were obtained for doses as low as 25 Gy. Egg hatch was inhibited for irradiated males crossed with irradiated females at a low dose of 20 Gy. However, we estimated that to achieve 99.9% sterility (standard goal of many sterile insect technique programs), irradiation doses had to be increased to a dose between 50 and 75 Gy. At doses of 25 Gy and greater, we observed a decreasing trend in adult flight ability and an increasing trend in adult mortality. Such differences were greater for pupae irradiated at a young age compared those irradiated 24 h before emergence. Our single most relevant finding was that sterility induction (i.e., oviposition of nonfertilized eggs) was two times greater for males irradiated at low doses (40 Gy) than for males irradiated at high doses (80 Gy) when used at a 3:1:1 sterilized male to fertile male to fertile female ratio. Males irradiated at high doses may have been outcompeted by unirradiated males when courting unirradiated females. Implications of our findings for sterile insect technique programs are discussed.

Effect of gamma radiation on the male sterility and other quality parameters of peach fruit fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae)

“…Collins et al 2008Collins et al , 2009). However, in choosing an optimal sterilization dose for SIT, a balance needs to be reached between the levels of sterility and mating competitiveness of males (Toledo et al 2004;Parker, Mehta 2007). Insects that receive a too low dose are not sufficiently sterile and those that receive a too high dose may be uncompetitive, reducing the effectiveness of SIT as it requires that There appears to be a general consensus that the irradiation process negatively affects the total competitiveness of males (Pereira et al 2007) and that one simple way to lessen this impact, and thereby to increase the effectiveness of SIT, is to reduce the sterilizing dose (Shelly et al 2005).…”

Optimizing Irradiation Dose for Sterility Induction and Quality of <I>Bactrocera tryoni</I>

“…But such practices can diminish ultimate SIT efÞcacy if higher irradiation doses diminish ßy performance. Deleterious effects of gamma irradiation on ßy quality and competitiveness have been reported for numerous tephritid species, including C. capitata (Lux et al 2002, Barry et al 2003, Anastrepha obliqua (Macquart) (Toledo et al 2004), Anastrepha ludens (Loew) (Rull et al 2007), Anastrepha suspensa (Loew) (Walder and Calkins 1993), and Bactrocera cucumis (French) (Hooper 1975). For effective SIT, it is essential that irradiation procedures be Þne-tuned to ensure an adequate level of sterility while minimizing the deleterious effects on ßy quality and competitiveness.…”

The development of new radiation protocols for insect sterilization using long wavelength x-rays

“…Another example is the eradication of the tsetse fly Glossina austensi Newstead from the island of Zanzibar [18]. Other pests that have been targeted with SIT include the Mexican fruit fly Anastrepha ludens (Loew) in the Southern USA and Mexico [19], the melon fly Bactrocera cucurbitae in Japan [20], the onion fly Delia antiqua (Meigen) in The Netherlands [21], the codling moth Cydia pomonella (Linnaeus) in British Colombia [22] and the pink bollworm Pectinophora gossypiella (Saunders) in California [23]. SIT projects are also in progress against the Mediterranean fruit fly (medfly) Ceratitis capitata Wiedemann in Central and South America, parts of southern Europe, South Africa and Australia [24].…”