My 4 year old niece wanted to know why earwigs have to pinch. I told her they have those big ‘pinchers’ so they HAVE to use them. Right? But really evolution gave them those pincers, which are modified cerci, for catching prey and for fighting over females thus the males have bigger pincers. They are also used by the insects to fold their wings back under the elytra. Yes, wings. Earwigs are their own order made up of over 2,000 species, called Dermaptera. Loosely translated that means “skin-wings”. Their wings are not often seen, but are thin and resemble skin thus the name. These thin wings allow them to fly similar to a rove beetle or June bug. They are night fliers, so most people don’t see them flying. I remember when I was younger I saw a male earwig using its cerci to fold its wings under the hard fore-wings, it was a sight to see. Captivated me for the whole 60 minutes, all the tucking and folding, twisting and turning using those forcep-like cerci at the end of its abdomen.
What makes earwigs one of my favorite insects, though, is how the mother takes care of the young. She makes a nest in a damp spot such as under a log or rock, and rolls and licks the eggs keeping them free from fungus. She also keeps them safe from predation by moving them if a predator is near. After the young are born they stay with the mother through the first 2 instars (first two molts) when she feeds them regurgitated food. It has been recorded that after these two molts, the mother dies or not, either way the offspring eat her*. This is called Matriphagy and is rare in the insect world. All in all, though, Agatha Christi was right, earwigs make good mothers. (If you don’t know what that means, read Agatha Christi’s books until you do. Then finish reading all the rest if you haven’t yet, then read them again in 10 years. I will do your brain good.)
As an added note, earwigs rarely pinch. You have to put your hand down on them or threaten them in a manner that they will retaliate with a small pinch, but overall they won’t go out of their way to pinch you. Nor do they have any venom or poison in that pinch, so the pain won’t last.
*Suzuki, S. Kitamura, M. Matsubayashi, K. (2005). “Matriphagy in the hump earwig, Anechura harmandi (Dermaptera: Forficulidae), increases the survival rates of the offspring”. Journal of Ethology 23 (2): 211–213.