Wednesday, July 9, 2008

Better Know an Insect: Femme Fatale Fireflies

Last night Dustin and I took an evening stroll through the park. It was a lovely, warm evening, with robins singing from the treetops and a slight breeze rustling the grass. And, of course, there were fireflies, lighting up the summer night with their romantic display, a visual analog to a bird's song.

Males, seeking females, blink their message in code, while females sit and wait on the ground for the right guy to come along. When she sees him, she blinks back until he finds her, and that's where baby fireflies come from. Aww.

Unless she's a hungry female of the genus Photuris, that is.

After Photuris females have mated, they don't need to mate again. But why waste a perfectly good signaling device? Instead, the Photuris females signal back to males of another species, Photinus, luring them in and catching them for dinner. Delicious!

But he's not just a tasty meal to help her lay eggs. It turns out that Photinus males produce a chemical that protects them from attacks by spiders and other arthropod predators. By eating Photinus males, the Photuris female acquires this armor and is herself protected from attack.

So, the next time you're out for an evening stroll in July, consider the drama playing out before you. There are dangerous femme fatales everywhere you look.

Read more about it on this page from Cornell.


Dustin said...

Given enough time, the different species of fireflies will eventually evolve the ability to carry out public key cryptography with binary blinking, removing the possibility of getting eaten by l33t firefly spoofing h4ck0rs.

Margaret said...


That is really interesting - how devious and yet efficient at the same time. Go femme fatale fireflies!

mama B (heh!heh!)