Tsetse fly pheromones that could help curb the diseases they spread

New knowledge about tsetse fly mating could bolster the arsenal of tools to control the spread of disease by these insects, which cause life-threatening diseases in much of sub-Saharan Africa and whose reach is about to expand with a changing climate.

Insects produce volatile pheromones that control their mating behavior; however, despite more than a century of research on the tsetse fly, its volatile sex pheromones had not been previously identified.

Tsetse flies transmit trypanosomes, single-celled parasites that cause trypanosomiasis in humans and animals.

For decades, the main means of controlling these diseases has been to control the tsetse flies that spread them.

The most common and effective method is the use of scent traps that attract flies by using odorants derived from the animals they feed on.

However, since insect-derived pheromones have been used successfully to control a wide range of other insects, their identification in tsetse flies could prove useful for their control.

Female tsetse fly. (Photo: Peggy Greb/USDA Agricultural Research Service)

To identify volatile pheromones from the tsetse fly, Shimaa Ebrahim’s team at Yale University in the United States used a variety of approaches, including gas chromatography, mass spectrometry, electrophysiology, and behavioral analysis in studies of the tsetse fly Glossina morsitans.

Through this analysis, Ebrahim and colleagues discovered several volatile compounds (methyl palmitoleate (MPO), methyl oleate, and methyl palmitate) that promoted rapid mating behavior in G. morsitans under experimental conditions.

Furthermore, they characterized a subpopulation of olfactory neurons in flies that respond to these pheromones.

The findings also revealed that infection of female tsetse flies by trypanosomes alters both the pheromone profile and the mating behavior of the flies and has the effect of reducing mating receptivity in females.

The study is titled “A volatile sex attractant of tsetse flies”. And it has been published in the academic journal Science. (Source: AAAS)