Finding a mate can be hard. Take the case of fireflies in many areas of the world. In the dark of night, they call to potential mates using the glowing chemical lamp in their abdomen. In one species of tropical Asian firefly, both males and females flash their signals into the darkness. Females have just one lantern in their abdomen and flash in slow single pulses. Males flash in quick succession from two abdominal lanterns. In 2024 an international team of biologists reported their finding that sometimes, instead of love, a fiendish trap may await these male fireflies summoned by what seems to be the flash pattern of a female.
The scientists were studying a species of garden spider found in China that spins its web at night. The researchers found some of these webs were full of trapped male fireflies. Why did the spider catch so many male fireflies? The researchers found that when a male firefly was trapped in the web, the spider wrapped it in silk and injected it with paralyzing venom, much as it would any other prey.
But, while the spider often kills and eats other victims right away, it leaves trapped male fireflies. The trapped fireflies continue to flash, but now with slow single pulses more like the female’s. The trapped firefly is transformed into a living lure, drawing other male fireflies to their doom. What causes the transformation? The researchers think that the changed flashing pattern may be due partially to stress, but mostly due to either the spider’s venom or the patterns of its bites. Further experiments will be needed to learn more.
This moment of science comes from Indiana University, with production support from the Office of the Provost.
I'm Yaël Ksander.
