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Weird & Wild: Bugs’ Battle of the Sexes

By Christine Dell’Amore

When it comes to animal mating, males usually call the shots.

Not so for the extinct mite species Glaesacarus rhombeus, whose females may have had total say over sex, a new study says.

Scientists discovered this gender role reversal while studying a “exceptionally well-preserved copulating pair” of mites trapped in amber. (See pictures of animal pairs.)

Frozen in the act 40 million years ago, the mites both have unique reproductive structures–at least when compared with most modern-day
mites.

Mite1.jpg

Side view of the mating mites, with the male to the right. (Credit: Ekaterina Sidorchuk)

For one, the female had a pad-like projection on her rear that gave her control over how long the male could cling to her. Usually it’s the male
that has this specialization, but it was absent in male
Glaesacarus rhombeus, the researchers found.

Lest you’re left wondering about what these adaptions look like, they’re spectacularly exemplified in the “torture phalluses” of the seed beetle(see pictures of the phalluses).

Male beetles with the longest spines are more successful in reproducing than their less endowed rivals, according to a
study I reported on in 2009.

Even so, the female gets the short end of the stick. These “medieval torture instruments” will “literally injure females internally in their copulatory duct,” Göran Arnqvist, an evolutionary biologist at Sweden’s Uppsala University, told me. “They’re pretty mean.”

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The spiky genitalia of the male C. analis seed beetle. (Credit: Johanna L. Rönn/Uppsala University)

But in the ancient mites’ battle of the sexes, the female seemed to come out on top.

“Female control over mating may reduce the timing of insemination, harassment by males, and damage caused by copulation,” the study authors write in the March issue of the Biological Journal of the Linnean Society.

There are still some living examples of this female power–notably some mites that have “developed female copulatory tubes that function like a
penis,” study leader
Pavel Klimov of the University of Michigan Museum of Zoology said in a statement.

In honor of the strange world of insect mating, I’ll close with a few more scintillating selections from the National Geographic News archives:

Cricket Has World’s Biggest Testicles (But Puny Output)

Female Flies Put Up a Fight to Keep Sex Short

Beetles Are Thirsty for Sex

Check out more weird coverage on National Geographic News.