For glowworms, the brightest girls get the guy

For much of the animal kingdom, females aren’t usually the ones that show off for potential suitors. But for a species of glowworm in Finland, the females that glow the brightest are not only the most fertile, but they’re also the most pursued by male glowworms, the researchers report October 21 in Biology Letters.

 In the nocturnal Lampyris noctiluca, the wingless females use a green glow to attract flying males in the dark.  The researchers found that males preferred brighter females and that females with bigger glowing structures laid more eggs.

Since males can’t accurately judge a female’s size in the dark, the glow could be the first indication of a healthy mate, the scientists write.