Older male burying beetles make better fathers than younger beetles as they put more effort, according to a new study conducted by researchers at University of Exeter.
The study found that mature males, who had little chance of reproducing again, invested more effort in both mating and in parental care than younger males.
The study considered how the likelihood of paternity influenced the way that males cared for young. Older males were good fathers and looked after the young even when they were unsure whether the offspring were theirs. Younger males, who had a higher chance of reproducing again, tended to care less for offspring, particularly when they were uncertain of their paternity.
The survival and performance of the offspring remained the same regardless of the level of care provided by the males. This is because when the father stopped pulling his weight, the mother took up the slack and provided the additional care necessary to produce successful offspring.
"Our research shows that age has a direct impact on the level of parental care given by male burying beetles. If their chances of reproducing again were high, we found that males had to make a trade-off between the likelihood of paternity and the level of paternal care they would give. We found that younger males who were uncertain of their paternity were likely to make the worst fathers," said Dr Megan Head from the University of Exeter.
The results of the study support the hypothesis that in species with paternal care, fathers are expected to balance investment in future reproduction with care for current offspring to maximise their lifetime reproductive success.
The study was published in the journal Proceedings of the Royal Society of London - B.