2-Butanone as a carbon dioxide mimic in attractant blends for the Afrotropical malaria mosquitoes Anopheles gambiae and Anopheles funestus

Most odour baits designed to attract host-seeking mosquitoes contain carbon dioxide (CO ), which enhances trap catches, given its role as a mosquito flight activator. However, the use of CO is expensive and logistically demanding for prolonged area-wide use. This study explored the possibility of replacing organically-produced CO with 2-butanone in odour blends targeting host-seeking malaria mosquitoes. During semi-field and field experiments MM-X traps were baited with a human odour mimic (MB5 blend) plus CO or 2-butanone at varying concentrations. Unbaited traps formed a control. The attraction of Anopheles gambiae s.s., Anopheles arabiensis and Anopheles funestus to these differently baited traps was measured and mean catch sizes were compared to determine whether 2-butanone could form a viable replacement for CO for these target species. Under semi-field conditions significantly more female An. gambiae mosquitoes were attracted to a reference attractant blend (MB5 + CO ) compared to MB5 without CO (P