June 14, 2009
Strange BiologyFemme Fatales Fireflies
While the BioZine is on summer vacation, enjoy this article from the archives. This article was originally published in October 2007.
A female Photuris firefly eats a male Photinus firefly.
All the fireflies you see flashing on a summer evening are not necessarily of the same species. Each different flash pattern usually indicates a separate species. However, the females of the genus Photuris have evolved the ability to mimic another species flash pattern. Why do they want to attract the wrong species?
Cornell University professor Thomas Eisner along with his two postdoctoral fellows, Michael Goetz and David Hill, studied the behavior of females fireflies of the genus Photuris. "To many of us, there's something intriguing and even romantic about fireflies in the night. Certainly some — but not all — of those fireflies have romance on their minds," Eisner was quoted as saying in a Cornell University press release about the research. "Generally, courting males are the fancy flashers, and they signal with their light organs in characteristic, species-specific patterns of flashes. They watch for females to respond to their pattern with single flashes."
They found that Photuris females have a flash pattern that attracts males of their own species. But the researchers also found that Photuris females also imitate the female flash signal of the genus Photinus within the same habitat. The Photuris females use this false flash to attract Photinus males. Photuris females don’t want to mate with Photinus males. These deceptive females have dinner in mind instead.
A female Photuris firefly that lacks the defensive chemical is eaten by a spider.
The Photuris females don’t eat from hunger; they take a meal for protection. The Photuris females do not possess a chemical repellent in their blood which Photinus and other species of fireflies produce to keep predators, such as spiders and birds, at bay. Photuris females get the defensive chemical they need when they eat other fireflies. How does the male get deceived? The Photuris female copies the amount of time a Photinus female delays before exhibiting one flash in response to Photinus male flashing. Although the mimicry may not be exactly right, it is often close enough for the male to make a deadly mistake.
While the Photinus males do not benefit from the adaptation, the Photuris females have evolved a survival strategy that has proven success. "This strategy — acquiring ready-made defensive chemicals from other organisms — turns out to be quite common in nature," Eisner said in the press release. "The more we study insects, the more we find them taking chemical defenses from plants and from other insects. And plants are 'experts' at gleaning useful chemicals from microorganisms.”
More to Explore
- Lured and Liquidated, Gullible Male Fireflies Supply 'Femmes Fatales' with a Lifesaving Chemical
- Shunning the night to elude the hunter: diurnal fireflies and the “femmes fatales”
- Firefly "femmes fatales" acquire defensive steroids (lucibufagins) from their firefly prey
- Biologists Expose Hidden Costs Of Firefly Flashes: Risky Balance Between Sex And Death
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