Genetic elimination of field-cage populations of Mediterranean fruit flies

Abstract

The Mediterranean fruit fly (medfly, Ceratitis capitata Wiedemann) is a pest of over 300 fruits, vegetables and nuts. The sterile insect technique (SIT) is a control measure used to reduce the reproductive potential of populations through the mass release of sterilized male insects that mate with wild females. However, SIT flies can display poor field performance, due to the effects of mass-rearing and of the irradiation process used for sterilization. The development of female-lethal RIDL (release of insects carrying a dominant lethal) strains for medfly can overcome many of the problems of SIT associated with irradiation. Here, we present life-history characterizations for two medfly RIDL strains, OX3864A and OX3647Q. Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males. We also present the first proof-of-principle experiment on the use of RIDL to eliminate medfly populations. Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication. The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.

Evolutionary biology and genetic techniques for insect control

“…; Leftwich et al. ). Any fitness loss of the GM strains can normally be countered by procedures such as increasing the frequency or number of released individuals.…”

“…Caged and field‐caged trials of RIDL medfly ( Ceratitis capitata ; Leftwich et al. ), olive fly ( Bactrocera oleae Gmelin; Ant et al. ; Harvey‐Samuel et al.…”

“…), any such benefit is negated as male RIDL larvae survive and continue to damage fruit (Leftwich et al. ). In contrast, for non‐RIDL programs that target vectors of disease such as mosquitoes, transgenes that act to reduce the probability of disease transmission should ideally be much later acting in order to enhance additional control arising from increased density‐dependent mortality among larvae (which do not themselves cause disease, e.g., Wise de Valdez et al.…”

“…A goal in developing and assessing new methods, and in refining existing ones, is to understand whether it is ultimately better to optimize control strategies over a range of different species, environmental, and biotic conditions, or instead to employ highly species‐ and/or environment‐specific targeting (see section , below; Leftwich et al. ).…”

Sustainable Agriculture and Climate Change

“…The same technique has been used successfully to control the fruit flies, B. oleae [107] and Ceratitis capitata (Wiedemann) [108], and the mosquito, Aedes aegypti (L.) [109]. However, this has not yet been considered in SA, probably due to the controversy surrounding genetically modified organisms.…”