Lucy Cooke reveals how flashy female fireflies fool hapless males
FIREFLY
On a balmy summer’s evening in Massachusetts, I was lucky to witness thousands of fireflies carving their illuminated arcs into the night sky. These synchronised courtship dances are a true spectacle. Male fireflies blink their bioluminescent love code into the sky while females, waiting in the grass, respond with their own sexy signal. If all goes well, these flashy characters will meet and mate. But within this magical display lurk femmes fatales using this sparkling dating scene as a cloak for cannibal warfare.
Each of the hundreds of different firefly species has its own pattern of light emissions that identify it. I’d joined two entomologists, Andy Moiseff and Chris Cradsley, who cast pulsing lights on fishing lines into the night to crack the firefly code. They told me how one species may have a single short blip of light repeated at regular intervals, while another species may turn its luminous organ on and off in a different pattern. These distinct codes enable fireflies to find the right species partner on a crowded flashy night.
The female of the species Photuris versicolor has evolved to exploit this system, however. She mimics the flashy love language of the Photinus genus to attract their males rather than those of her own species. When a Photinus male lands in the grass hoping to consummate his desire, this deceptive flasher doesn’t mate with her would-be lover; she captures and eats him instead.
There are plenty of infamous invertebrate females, from spiders to praying mantis, that eat their lovers in order to nourish their developing eggs. At first it was assumed Photuris was doing the same, albeit with another species, which is perhaps a more socially acceptable form of sexual cannibalism. But it turns out Photuris isn’t
