Responses of Glossina pallidipes tsetse fly to geosmin, 2-pentanol and carbon dioxide odour cues

Abstract

Tsetse flies exhibit varying host preferences when seeking blood meals. Volatile organic compounds from preferred hosts such as buffalo and cattle have been used to develop the 3-n-propylphenol, 1-octen-3-ol, p-cresol and acetone (POCA) attractant blend, but its attraction is only about 25% of that of natural hosts, necessitating improved attractants. This study evaluated laboratory and field behavioural responses of Glossina pallidipes to geosmin, hexanal, 2-pentanol and carbon dioxide (CO2), compounds known to elicit strong responses in other insects. Laboratory two-choice olfactometer assays showed dose-dependent attraction to all tested compounds, with significantly more flies choosing treatment arms than control arms (p < 0.05). Field responses to geosmin and CO2 were validated using a randomized Latin square design, in which traps baited with either odour captured significantly more tsetse flies than unbaited control traps (p < 0.05). These findings identify geosmin, 2-pentanol and CO2 as promising odour cues for enhancing POCA attractant blends for G. pallidipes. Incorporating these compounds into existing odour-bait systems could improve the effectiveness of environmentally friendly and cost-effective tsetse control strategies.