C.S. Brent et al., “An insect anti-antiaphrodisiac,” eLife, 6:e24063, 2017.
Many male insects deploy “mate-guarding” chemicals that render females unattractive to other males for some time after copulation. The technique gives males’ sperm a competitive edge, but can disadvantage females if the effect lasts too long.
In a first, Colin Brent of the US Department of Agriculture’s Arid Land Agricultural Research Center and colleagues stumbled on a female means of fighting back. In the western tarnished plant bug (Lygus hesperus), males’ seminal fluid contains antiaphrodisiac pheromones. Over several days or weeks, females convert one of those compounds to geranylgeraniol, which counteracts the antiaphrodisiacs to reveal that she may, in fact, be ready to mate again. “[They’re] basically competing signals,” Brent says.
“This means that the female bugs are not just passive subjects, but they can actively influence the communication and mating system,” Sandra Steiger of Ulm University who was not involved in the study tells The Scientist in an email. Females continue to produce eggs throughout their lives, so reducing the time between new mates may enable them to have genetically more-diverse offspring, Brent says.
Female Drosophila had been known to eject an antiaphrodisiac compound from her reproductive tract, but this is the first known instance of an insect countering such a pheromone with a signal of her own. The study’s authors predict that more anti-antiaphrodisiacs will be found now that researchers know to look for them. “We need to deepen our understanding of the female part” in post-mating chemical communications, says Steiger.