Contamination of nectar sources and pollinators with an insect growth regulator when using autodissemination approaches for mosquito control

The control of container inhabiting mosquito species such as Aedes albopictus and Aedes aegypti is often difficult because larvae occupy cryptic habitats, which are hard to locate and treat with conventional insecticidal techniques. Autodissemination approaches to target container inhabiting mosquitoes have been shown to be successful at reducing larval and adult mosquito populations. Autodissemination approaches are based on mosquitoes themselves acting as insecticide delivery vehicles that are effective in reaching the cryptic larval habitats. The most used group of insecticides for autodissemination approaches are insect growth regulators (IGRs). The IGR pyriproxyfen is lethal in the parts per billion to the juvenile stages of mosquitos. Although the dissemination of small amounts of pyriproxyfen seems like an advantage over more traditional forms of pesticide applications for mosquito control, the use of autodissemination approaches could lead to the unintended transfer of pyriproxyfen from the contaminated mosquitoes to the nectar sources and to the pollinators visiting the same nectar sources. In this study, we examined the cross-contamination of PPF from mosquitoes to natural and artificial nectar sources and painted lady butterflies (Vanessa cardui) in semi-field cages using the release of treated Ae. albopictus males and an autodissemination station. The data suggest the transfer of PPF to nectar sources and V. cardui associated with autodissemination approaches. The results are discussed concerning the potential effects on non-target insect pollinators when using autodissemination approaches for mosquito control.