A baby's cries for food might drive a tired parent to aggravation. But some species take more drastic measures. Like the burying beetle, Nicrophorus vespilloides—which punishes its pesky children by eating them.
Researchers wanted to get to the bottom of an age-old question in evolutionary biology: the origin of begging. Natural selection favors a greedy, well-fed child. But it also favors parents who dole out food evenly to their young, and save some for themselves.
So how do you resolve that parent-child conflict? Burying beetles do so by putting the ultimate price on pleading: death. Begging larvae were 13 times more likely than laid-back larvae to be eaten by mom. Which may discourage them from asking for more than their fair share of the grub. That finding appears in the journal Behavioral Ecology. [Clare P. Andrews and Per T. Smiseth, Differentiating among alternative models for the resolution of parent–offspring conflict]
Humans have different standards than beetles do, of course. For us, pestering your parents may be a good thing. One study [Virpi Lummaa et al, Why Cry? Adaptive Significance of Intensive Crying in Human Infants, in Evolution and Human Behavior, 1998] suggests crying is a sign of good health, which might lower a baby's chances of being neglected or abused. Then again, after those first few years, you're probably better off not being a crybaby.
[The above text is a transcript of this podcast.]