Gamma Irradiation and Male Glossina austeni Mating Performance

Abstract

An area-wide integrated pest management (AW-IPM) strategy with a sterile insect technique (SIT) component has been proposed for the management of African animal trypanosomosis (AAT) in South Africa. In preparation for the SIT, the mating performance of colony reared Glossina austeni males under influencing factors such as radiation dose and the development stage that is exposed to radiation, was assessed under laboratory and semi-field conditions. The radiation sensitivity of G. austeni colonized 37 years ago when treated as adults and late-stage pupae was determined. Radiation doses of 80 Gy and 100 Gy induced 97–99% sterility in colony females that mated with colony males treated as adults or pupae. Males irradiated either as adults or pupae with a radiation dose of 100 Gy showed similar insemination ability and survival as untreated males. Walk-in field cage assessments indicated that a dose of up to 100 Gy did not adversely affect the mating performance of males irradiated as adults or late stage pupae. Males irradiated as adults formed mating pairs faster than fertile males and males irradiated as pupae. The mating performance studies indicated that the colonized G. austeni males irradiated as adults or late stage pupae will still be suited for SIT.

Quality Control and Mating Performance of Irradiated Glossina palpalis gambiensis Males

“…As a result, these findings suggest that the irradiation dose currently used to sterilized tsetse flies could be optimized according to the dose rate. This parameter was not taken into account in past studies [ 17 , 31 , 41 , 42 , 43 ] and the fine tuning of the dose and dose rate and could lead to more competitive sterile males.…”

The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010–2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique

“…A dose of 40 to 80 Gy induced 97–99% sterility in G. brevipalpis females when mated with males irradiated as late-stage pupae or adults [ 181 ]. Higher doses, 80 to 100 Gy, were required for G. austeni males irradiated as late-stage pupae or adults to induce similar levels of sterility in females [ 182 ]. The mating performance of colony flies irradiated as adults and late-stage pupae, as investigated in walk-in field cages, indicate the irradiated males to be as competitive to mate with females as un-irradiated males [ 181 , 182 ].…”

Sterile Insect Technique (SIT) and Its Applications

“…Mating performance of irradiated male insects is one of the key factors that need to be evaluated before the implementation of SIT releases. De Beer and colleagues (2020) [ 24 ] report that irradiation of Glossina austeni males from a 37 year-old colony as adults or late stage pupae to obtain ca. 99% sterility did not affect their mating performance, and it was concluded that these sterile males are suitable for SIT applications as shown in laboratory and semi-field experiments.…”