Beetle Moms Make Anti-Aphrodisiac to Keep Dads Focused on Parenting

"Not tonight, honey," says the female burying beetle, chewing up a mouthful of mouse carcass before spitting it into the mouth of a begging larva. For the first few days of their babies' lives, burying beetles co-parent. They devote themselves to keeping their squirming larvae alive. That means mating and laying more eggs would be a waste of energy. And to make sure males get that message, females emit a pheromone that turns them off. "It is quite surprising," says University of Ulm behavioral ecologist Sandra Steiger, "and somehow intriguing." Steiger and her coauthors discovered the anti-aphrodisiac in a detailed series of experiments. The burying beetles they studied (Nicrophorus vespilloides) have unusual lives to begin with. First, a pair of beetles claims a fresh animal carcass as their temporary kingdom. They mate and lay eggs in the decaying body. After the eggs hatch, the larvae spend about three days begging ...