For male sexton or burying beetles Nicrophorus vespilloides, fatherhood is not for the faint-hearted, says Stuart Blackman.
The first job is to scour the countryside for a dead mouse. This must then be stashed in a subterranean crypt, stripped of its fur and embalmed in antibiotic fluids. The next week or two is spent regurgitating partially digested mouse meat to a brood of about 30 wriggling maggots that even sit up and beg for food, like chicks in a nest.
- What was the first animal to have sex?
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Others might expect that such a monumental effort is only possible for males in their prime. And yet new research shows that it is older, more decrepit males that make the best, most attentive fathers.
It's not the wisdom of old age that counts - it's that elderly males have fewer options open to them. For younger ones, with a lifetime ahead of them, making a large investment in the current brood will use uptime and energy that could be better spent raising more families in the future.
For seniors, though, the chances are there won't be a tomorrow, so it pays to put everything they have into the current brood.
Indeed, elderly males work just as hard even if there is a good chance that the brood they are caring for is not their own. Younger bucks, however, need only get a whiff of another male about the brood chamber and they disappear to look for a different carcass.
It is not only the maggots that benefit from having an older male around. Females can afford to take things easier when they are paired with more mature mates.
"Females should prefer to mate with older males because they work harder and care less about infidelity," said Exeter University's Nick Royle, who led the research. Whether they actively choose older partners, however, is still not known.