Zoologger is our weekly column highlighting extraordinary animals – and occasionally other organisms – from around the world.
Species: Nicrophorus vespilloides
Habitat: Throughout the northern hemisphere, variously in bogs and open forests. Associated with corpses
Squeamish readers might want to look away: this is a tale of decaying corpses, regurgitation and feasting on putrefaction. It is also an account of some excellent parenting skills.
We’ve all seen baby birds begging their parents for food. The larvae of the burying beetle Nicrophorus vespilloides do it too, only their diet is… well, slightly different.
The story begins in a forest in northern Europe, where a small bird has died and fallen to the ground.
A pair of burying beetles, one male and one female, claim the body and begin to dig away the soil beneath it, so that the corpse gradually sinks into the ground and eventually becomes covered in soil. They bury the body in this way to keep it to themselves, safe from the hordes of other organisms eager to feed on it.
Once it is safely underground, they strip off the feathers (or fur if it is a mammal) and use them to line the “crypt” containing the corpse. To hold off microbes, they exude antibacterial liquids from their anuses; the females take the lead on this. Then they shape the flayed body into a rough ball, and scratch out a small crater on the top.
Now the happy couple are ready to start a family, and the female lays her eggs in the soil around the body. When the larvae hatch, they make their way to the crater and begin feasting on the decaying flesh.
But a hungry larva wants more! Like a cute little toddler, it will sometimes approach one of its parents, nuzzling their mouthparts with its head while stroking them with its legs. This is how they beg, and if the fond parent is so inclined it will regurgitate some liquid carrion.
The parents are attentive and responsive to their offspring’s demands, and the larvae are good at getting what they want. They start begging more if one of the parents (more often the male) abandons them, and they also beg more if there are many larvae in the brood.
It seems that begging behaviour is at least partly hormonal: larvae with increased levels of juvenile hormone do more begging.
But Per Smiseth and colleagues at the University of Edinburgh, UK, have recently discovered that the larvae may be “encouraged” to beg by chemicals on their parents’ bodies. The offspring could be persuaded to beg for food from pieces of filter paper that had been rubbed against their mothers. But larvae begged their mothers less if their mothers had had their bodies washed.
Journal reference: Behavioral Ecology, DOI: 10.1093/beheco/arq019