Mating mites trapped in amber show the female in control

Some 40 million years ago, the Glaesacarus rhombeus female mite made the mating choice. A pair of mites trapped in amber tells the tale.

A pair of mating mites caught — literally — in the act 40 million years ago by oozing sap show that once upon a time, mite females made the mate choices. In a report published in the Biological Journal of the Linnean Society, researchers Pavel Klimov and Ekaterina Sidorchuk tell the tale of the mating mites immobilized eternally when that flowing sap hardened into amber.

These extinct mites, they say, left the male at the mercy of the female when it came to mating, a situation very different from how today’s mating mites manage it.

Alliteration aside, the war between the sexes has always involved tension over who controls the mating. These Glaesacarus rhombeus mites seem to have had it all backwards from many of today’s similar mite species. The ancient arachnids (mites, like scorpions and spiders, are arachnids) lacked the clinging structures that male mites use today to keep the female in thrall, but the ancient female mite was well equipped to keep a male right where she wanted him. In the amber-ensnared mite couple, the female sports a special pad-like structure that she used to hold the male during copulation.

Why does it matter which mite is in control? When a female is in charge of mating, things change. She avoids expending energy on fighting off unwanted advances or dealing with copulation-related injuries. Both members of a mating pair are less distracted and can focus on other important things, like noticing if they’re about to become dinner. Interestingly enough, with females in charge, males don’t have to spend as much time fighting each other for the girl, either. In fact, having females control mating seems like such a great idea, it’s a wonder more species haven’t developed the tactic.

But plenty of species haven’t. Males often dominate females in the mating dance, and many of today’s mites are no exception. There are benefits to males when they’re in control: A male mite can, for example, keep an alluring female to himself if his clinging apparatus literally holds her in place, ensuring she mates only with him. Males can be so jealous that they’re willing to expend energy guarding the female before and after mating. They’ll even harass mite females who just aren’t that into them.

An ant trapped in amber. Organisms trapped in amber have yielded many secrets about how they lived millions of years ago. Via Wikimedia Commons.

So, the war between the sexes—and which sex has the upper place in mating — rages on … and on. According to Klimov and Sidorchuk, this petrified pair of mites in amber tells us that about 40 million years ago, the Glaesacarus rhombeus female mite was responsible for the mate choice, even though today, the clingy male makes the decision.

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