|Tiger Fireflies feeding on other fireflies.|
Friday, June 27, 2014
Femme Fatale Fireflies
While fireflies signal to each other and want to be noticed by other fireflies of the opposite sex, they sometimes attract the unwanted attention of the wrong fireflies. Some of these fireflies have ulterior motives. There is a whole genus of fireflies, the Photuris, or Tiger Fireflies, that are looking for other fireflies in order to eat them. These are larger than most others and you can usually see their whole heads and eyes protruding from under their pronotum, or shield-like appendage that covers the necks and heads, unlike many other fireflies.
Sometimes they just look for signalling fireflies (generally the males since they are the ones flying) and swoop down to capture them. Other times though, they have a much more devious way of catching their prey. They can actually mimic the light signals of some other fireflies to lure them in. These femme fatales then eat the confused suitor.
It is thought that a Photuris firefly can consume quite a few other fireflies during each night. They also can sequester the toxic alkaloids these other fireflies use to protect themselves to then protect the Tiger Firefly itself. Fireflies, like ladybugs, secrete protective chemicals from the joints of their legs in a process called "reflex bleeding." In addition to flashing to attract mates. all stages of fireflies can often flash, and this is thought to also serve as a warning signal of their distastefullness. Photuris need to obtain these protective chemicals from other fireflies. Their own species-specific flashes that they use to attract their mates are usually green as opposed to the yellow of the more common Photinus fireflies they prey upon, with at least one species producing a triple flash. One species of these femme fatale fireflies (there are thought to be 19 species in North America), the Pennsylvania Firefly (Photuris pennsylvanica) is the state insect of Pennsylvania.
So there are a lot flashers out there trying to attract mates in the firefly world. However, there isn't just seduction going on. There are also femme fatales out there luring males to their deaths, feeding and stealing from them what they need to survive. Such is the intrigue of the natural world at night, where everything is not as it seems and even beauty can have hidden dangers.