Female burying beetles (Nicrophorus vespilloides) release an anti-aphrodisiac pheromone that reduces mating attempts from their male partners during the time in which their offspring are in need of care, finds a study in Nature Communications. These findings shed light on the mechanisms underlying how insects modify their behaviour in order to provide parental care.
In the animal kingdom, parents are faced with the dilemma of whether to direct energy towards their current offspring (parental care), or towards future progeny - for instance, by producing new eggs. Burying beetles are known to exhibit biparental care, whereby females are aided by their male partners in feeding the brood. However, how the energetic and nutritional demands of the current brood and sexual activity are balanced has been unclear until now.
Sandra Steiger and colleagues analysed mating behaviour, hormone profiles, expression patterns of genes associated with hormone synthesis and egg production in about 400 beetles collected from a forest in Germany. They first show that female burying beetles display temporary infertility while their current offspring are most in need of parental care and that this infertility is mediated by a hormone called ‘juvenile hormone III’. They then show that this offspring-induced temporary infertility is signalled by the female to the male partner via a volatile chemical called methyl geranate (which is chemically similar to juvenile hormone III). Through several experiments, they show that release of this chemical reduces the number of mating attempts from the male partner.
Thanks to these chemical signals, female infertility and male sexual abstinence allow the parents to invest their resources into the developing larvae. In addition, the results point to an effective communication system between parents that benefits the parents themselves, and also their offspring.