The Loh Down On Science

The Beetles

She’s got a unibrow! He needs a manssiere!

This is Sandra Tsing Loh with the Loh Down on Science.

We all know that traits that are attractive in one sex aren't always so great in the other.

Humans cope through online dating, but what do other animals with tricky traits do?

Japanese and English ecologists attempted to find out, by studying the broad-horned flour beetle.

In these insects, big jaws are sexy in males, but not in females. Why? Because the same muscular body shape that can support big jaws in males makes it hard for females to carry eggs.

After mating generations of beetles of various jaw sizes together, here's what the team found: Large-jawed females more often produced sons, while small-jawed females more often had daughters. Oddly, the male’s jaw size didn't affect offspring sex ratios--only the female’s.

So the female is clearly in control, but how she does it?

Still a mystery. And big jaw or no, she's clearly not talking.



The Loh Down on Science, online, at lohdown.org. Produced by 89.3 KPCC and the California Institute of Technology, and made possible by TIAA-CREF.

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