Scientists have discovered that mother earwigs, vile little creatures that they are, select which babies are strongest based on their smell and take the best care of them. The weaker babies (or nymphs, as they’re known) are neglected, often to the point of starvation. This is a markedly different response than in many animals, which tend to, you know, nurture their young. From the BBC:
The insects pick up odours from their clutch of “nymphs” and adjust their maternal behaviour in response.
When they pick up a chemical signal from healthy, well-fed youngsters, they spend more time nursing them, at the expense of their hungrier babies.
The study, which is the first to show this behaviour in insects, is published in Proceedings of the Royal Society B.
Earwig parenting, it seems, is about favouritism; the standard of care drops dramatically when mums pick up the chemical signals from hungry, unhealthy nymphs.
In these cases, the adults invest less time and effort in feeding.
The researchers, who expected to see the opposite result, suggest that this could be “because the insects look for signals of quality instead of need”.
Earwigs ‘Sniff Out’ Best Babies [BBC]