Tsetse, a pest in sub-Saharan Africa, is notorious for spreading diseases to humans and livestock through the trypanosome parasites they harbor. Baiting traps with volatile pheromones, or odors that attract mates from a distance, is a promising strategy for controlling these blood-sucking insects. “Scientists have been studying tsetse for over 100 years, but no one has actually found a volatile pheromone in this species,” said John Carlson, a biologist at Yale University. Now, for the first time, Carlson and his research team reported the discovery of volatile tsetse pheromones in a paper recently published in Science.1

Scientists have been studying tsetse for over 100 years, but no one has actually found a volatile pheromone in this species.

—John Carlson, Yale University

Carlson’s team concocted tsetse perfumes by soaking female flies in hexane. When the researchers spritzed the extracted female tsetse scents on a knotted string of black yarn, the male tsetse quickly attached itself to the aromatic decoy. Intrigued, Carlson’s team next ran a gas chromatography-mass spectrometry analysis on the fly extracts and identified six volatile compounds. 

The team found that one of these compounds, methyl palmitoleate (MPO), was a particularly strong attractant, arrestant, and aphrodisiac in the male tsetse. By measuring electrophysiological responses, the research team observed that MPO activated the same subset of olfactory neurons that respond to livestock odors currently used in tsetse traps, consistent with the idea that MPO activates a kind of attraction circuit. While the observations were specific to the tsetse species, G. moristans, similar approaches could reveal novel pheromones in other tsetse species.

One challenge is that the pheromone is most effective at short range. “If we know the receptors and the fidelity of these ligands, then we can modify the ligands to make them long-lasting and more volatile so they become long-range,” said Zain Syed, a chemical ecologist at the University of Kentucky, who was not involved in the work. 

Carlson is working with colleagues in Kenya to test MPO’s allure in the field. 


  1. Ebrahim S, et al. Science. 2023; 379:eade1877.