Female burying beetles focused on caring for their newborn offspring let males know they are temporarily infertile by releasing an anti-aphrodisiac chemical, or pheromone, that basically says, "Honey, I'm not in the mood."
This discovery was made by researchers from the University of Ulm in Germany, who focused their study on a beetle species, Nicrophorus vespilloides, known for burying carcasses of small animals like birds and rodents as food for their growing larvae.
Specifically, researchers found that female beetles stop producing eggs and release this chemical pheromone during a three-day period that is critical for raising their immature, wingless offspring, who cannot feed themselves.
In addition to preventing males from trying to copulate, these pheromones alert fathers - through sensory receptors in their antenna - that they need to help females with child care. This, researchers say, sheds light on how animals prioritize the needs of their young over sexual activity to produce new offspring.
"Our study helps to understand animal family life and how it is coordinated between family members," explained Sandra Steiger, lead researcher and assistant professor of biology at the University of Ulm. "It is kind of intriguing that such mechanisms exist in animals and that animal parents synchronize their mating and parental-care behavior for their own benefit and that of the children."
Burying beetles can be found in temperate regions of Europe, Asia and North America. Nicrophorus vespilloides measures about two centimeters long and is characterized by a black body marked with distinct bright orange patches.
Researchers studied a total of 400 beetle breeding pairs, collected from a forest in Germany. While a breeding pair appears to coordinate parental care, they don't mate for life.
Nonetheless, the three-day period of temporary infertility after the birth of offspring allows both males and females to focus on caring for the developing larvae.
"It certainly makes sense," Steiger added. "Why waste time and energy on copulation when she cannot produce eggs anyway and when it is necessary to raise the current offspring?"
After a few days of feeding, the beetles' larvae are finally ready to leave the carcass, at which time females will stop producing the pheromone, thus signaling to males it is time to start mating again.
Their findings were recently published in the journal Nature Communications.
