Think hard the next time you squish an earwig. If that earwig had babies, you’ve just orphaned them, thereby producing bigger earwigs.
One wouldn’t think that earwigs have much of a home life, but their family relationships are pretty well-studied. They make good research subjects because they reproduce quickly. Furthermore, Young earwigs can survive with or without parental care, so researchers can study two different models of family by looking at one bug.
A recent study took a look at young earwigs, known as nymphs, and how they got along both with and without maternal feeding and protection. One would expect animals that have to forage for themselves to be malnourished and scrawny, but nymphs that had been artificially orphaned grew bigger, both in body and in forceps (pinchers).
What’s more, depriving them of a mother’s care made them develop earlier, speeding through immature stages to become a fully-formed, giant adult earwig. Orphan an earwig and you get a super-earwig.
What you don’t get is a good mother. Maternally-deprived earwigs feed their own offspring less than maternally-reared earwigs. They also defend them less effectively. And the earwigs had one final trick up their metaphorical sleeves. The maternal neglect wasn’t totally the “fault” of the parents. The study states:
“Nymphs produced by maternally-deprived females were less well defended by foster mothers, but—when fertilized by maternally-tended males—received more food from foster mothers than nymphs produced by maternally-tended females. These results are overall in line with studies demonstrating that parent-of-origin effects inherited to and expressed by juveniles are key components of parental care.”
So earwigs will be foster parents. More importantly, this suggests that, in contest between nature and nurture, nature can produce greater results than we previously imagined. Maternal neglect, or maternal care, can produce physical changes in offspring that affect how the offspring are treated for generations.
Think about that the next time you fetch a rolled-up-newspaper.