Irradiation of <I>Anastrepha obliqua</I> (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.

Attractiveness and Sexual Competitiveness of Anastrepha obliqua Males (Diptera: Tephritidae) Fed on a Diet Enriched With Providencia rettgeri

“…Pupae were obtained from the Moscafrut (SADER-SENASICA) facility, located in Metapa de Dominguez, Chiapas, Mexico, from a colony that had been mass-reared for more of 150 generations (Orozco-Dávila et al, 2014). All of the pupae used in this study were irradiated for 48 h pre-emergence with 80 Gy of gamma radiation using a Cobalt 60 source (Toledo et al, 2004). The mass-rearing procedures and conditions followed those described by Artiaga-López et al (2004).…”

Quality Control Methods for Aedes albopictus Sterile Male Transportation

“…Additionally, the negative effects of radiosterilization on mating capacity and on longevity can be minimized by adjusting the timing of irradiation and the dose [9,12,13]. Earlier studies in fruit flies (Diptera: Tephritidae) have shown that both irradiation at high doses to achieve high rates of sterility [14][15][16] and mass rearing reduce the sexual competitiveness of sterile males in contrast to wild ones [15,17]. Besides the negative effects of mass production and sterilization on the quality of sterile males, transportation to release sites may induce an additional stress and, hence, deterioration of the quality.…”

Genetic pest management and the background genetics of release strains

“…Considerably less attention has been paid to the capacity for hybridization and gene flow between the released modified insects and wild ones. 'Sterilization' of males is rarely 100% effective, for example, because of a need to balance sterility and negative effects on performance in selecting radiation dose, or incomplete penetrance of genetic sterility [16,17]. Other GPM methods require fertile matings to allow introgression of novel traits into target populations [14]; in both cases introgression of background genetic material is likely.…”