Evaluation of radiation sensitivity and mating performance of Glossina brevipalpis males.

Chantel J De Beer,Hanano Yamada,Daphney Majatladi,Gert J Venter,Percy Moyaba,Marc J B Vreysen,Solomon N B Boikanyo,Philippe Solano

doi:10.1371/journal.pntd.0005473

Abstract

BackgroundArea-wide integrated pest management strategies that include a sterile insect technique component have been successfully used to eradicate tsetse fly populations in the past. To ensure the success of the sterile insect technique, the released males must be adequately sterile and be able to compete with their native counterparts in the wild.Methodology/Principal findingsIn the present study the radiation sensitivity of colonised Glossina brevipalpis Newstead (Diptera; Glossinidae) males, treated either as adults or pupae, was assessed. The mating performance of the irradiated G. brevipalpis males was assessed in walk-in field cages. Glossina brevipalpis adults and pupae were highly sensitive to irradiation, and a dose of 40 Gy and 80 Gy induced 93% and 99% sterility respectively in untreated females that mated with males irradiated as adults. When 37 to 41 day old pupae were exposed to a dose of 40 Gy, more than 97% sterility was induced in untreated females that mated with males derived from irradiated pupae. Males treated as adults with a dose up to 80 Gy were able to compete successfully with untreated fertile males for untreated females in walk-in field cages.Conclusions/SignificanceThe data emanating from this field cage study indicates that, sterile male flies derived from the colony of G. brevipalpis maintained at the Agricultural Research Council-Onderstepoort Veterinary Institute in South Africa are potential good candidates for a campaign that includes a sterile insect technique component. This would need to be confirmed by open field studies.

Highlights

Tsetse flies (Diptera; Glossinidae), the cyclical vectors of trypanosome parasites that cause human African trypanosomosis (HAT) and African animal trypanosomosis (AAT), infest 10 million km of sub-Saharan Africa [1,2,3]
It was showed that G. brevipalpis males were highly sensitive to irradiation and could be sterilised at a much lower dose, between 40 Gy and 80 Gy, than some other tsetse fly species
Males sterilised with a dose of up to 80 Gy performed similar as that of un-irradiated males for untreated females in walk-in field ages

Summary

Introduction

Tsetse flies (Diptera; Glossinidae), the cyclical vectors of trypanosome parasites that cause human African trypanosomosis (HAT) and African animal trypanosomosis (AAT), infest 10 million km of sub-Saharan Africa [1,2,3]. The use of sterile males to control field populations of insect pests, as conceptualised by E.F. Knipling in the 1940s [11,12,13], has been applied successfully to control tsetse fly populations. The first eradication campaign that integrated the use of radiation-sterilized adult male tsetse with suppression methods such as insecticide-impregnated targets, was implemented against Glossina morsitans submorsitans Newstead, G. p. All targeted populations of the four species were eradicated from the controlled zones These programmes, successful, were not conducted areawide, and their pest free status was lost due to reinvasion from neighbouring areas [13]

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Conclusion