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Mamoru Takata

Watch baby beetles beg for a meal of rotting flesh

What’s the difference between a suburban parent and a burying beetle? When the beetle wants to call the kids to dinner, it doesn’t stand on the porch and yell—it releases a pheromone called 2-phenoxyethanol, a chemical message that sets its brood begging. New research suggests the pheromone not only signals “suppertime!” but it may also prevent the babies from becoming supper, themselves.

Burying beetles (Nicrophorus quadripunctatus) lay their eggs in the decaying corpses of small animals such as birds and rodents. When larvae are young, the mother feeds them meals of regurgitated liquified flesh as often as three times per hour. Although the babies scramble to be fed at mealtimes, they are well-behaved in the intervening moments—even though mom is close by.

Researchers guessed that burying beetle mothers must somehow let their broods know when they are ready to spit up some snacks. So they analyzed all the gases and liquids emitted when a mother beetle fed her young. They discovered the feeding-time pheromone, 2-phenoxyethanol, wafting up from the regurgitated food. When they dangled 2-phenoxyethanol–laced filter papers in front of the larvae, the baby beetles raised the front ends of their pale, bulbous bodies to beg for a meal of partially digested rotting carcass, the researchers report today in iScience.

The pheromone message ensures that the larvae don’t waste precious energy begging. But it may also serve another purpose: protecting the beetle babies from being cannibalized. When there is not enough food to go around, burying beetle parents sometimes kill and eat their own offspring—and larvae that beg too much are usually the first to go.