Improving the handling, transport and release of sterile male mosquitoes as part of an area-wide integrated pest management strategy

The global burden of vector-borne diseases continues to grow year on year. Diseases transmitted by mosquitoes lead to more than 700,000 deaths each year, with malaria alone accounting for almost half a million of the total deaths. Such statistics underline the urgency for alternative complementary control measures. The sterile insect technique (SIT) is one of several genetic control measures routinely used throughout the world to suppress, contain or eradicate various species of agricultural, veterinary or human insect pests. SIT is a technique which has proved successful and sustainable, particularly when deployed as part of an area-wide integrated pest management programme (AW-IPM). A build-up of insecticide resistance coupled with the global spread of species such as Aedes aegypti and Aedes albopictus has reignited interest in developing mosquito SIT as part of an AW-IPM approach. Significant progress has been made in the last decade towards taking mosquito SIT to the operational level, however, distinct gaps still remain in the literature, especially regarding the post-pupal irradiation stages. The aim of this research thesis was to address some of the key issues where information was lacking, specifically the handling, transport and release of sterile male mosquitoes. The impact of immobilisation temperature and duration on male mosquito survival was investigated in Aedes aegypti, Aedes albopictus and Anopheles arabiensis, in order to determine a suitable storage and transportation temperature range when conducting releases of sterile male mosquitoes. The effect of compaction during storage was investigated and a maximum tolerable threshold determined. A standardised method to mark male mosquitoes for a small-scale field release was developed and verified in Aedes aegypti, Aedes albopictus and Anopheles arabiensis. A novel flight ability device, which aims to assess male mosquito quality was created and validated for Aedes aegypti, Aedes albopictus and subsequently modified and verified for Anopheles arabiensis.The effect of varying environmental conditions relating to the time of day that sterile male releases could occur was investigated for both male Anopheles arabiensis and Aedes aegypti. Finally, an adult aerial release device was developed in conjunction with the NGO WeRobotics and as part of a United States Agency for International Development grant. The system was successfully field tested in Brazil via a series of mark-release-recapture studies. As mosquito SIT nears the operational phase, it is hoped this research is a starting point when addressing some of the outstanding questions related to the handling, transport and release of sterile male mosquitoes.