Fireflies used as bait by spiders to attract more prey

Once the spider has captured a male firefly in its web, it turns the dead insect into food and uses its beacon light to lure in more prey.

New Hua Fu Researchers at China’s Huazhong Agricultural University found that male fireflies (Abscondita terminalis), but females of this species often get caught in the webs of orb-weaver spiders (Giant IsopodHe and his colleagues discovered that the spiders were using the flashing signals to lure the insects into their traps, and they wondered if this was what was luring them. Both males and females of this firefly species use flashing signals to court, with the females’ light shows drawing males to their location. So he and his colleagues investigated how the spiders were using this display of affection.

In farmland in China’s Hubei province, the team conducted a series of experiments on 161 different nests, some with spiders and some without. In each nest, the researchers placed male fireflies, some of which had painted the light areas of their abdomens black with ink. They found that nests that contained both spiders and free-flying fireflies attracted more male fireflies than nests without spiders or nests with only non-flying fireflies.

Also, the male fireflies that were tangled in spider webs emitted a different flash than normal — it was more like a female’s flash, emitting one flash instead of two — but the fireflies that were tangled in spider webs emitted normal flashes.

This suggests that the spiders manipulate the male firefly’s signals to mimic those of females and attract other males looking to mate, the team said. Lee Dae Geum The Hubei University researchers say they don’t yet know exactly how the spiders change the signals of their immobilized prey, but they have some ideas.

“The spider’s venom or the bite itself could lead to changes in the blinking patterns of captive males,” Lee said.

Li is interested to know if other spiders that eat fireflies use a similar strategy: Other animals may use different kinds of signals, such as sound or the release of pheromones, to bait their captured prey, he says.

“[The findings] “Spiders prove once again that they are not passive foragers.” Mariella Herberstein “We are discovering more and more cases of highly complex and selective feeding techniques,” say researchers from Australia’s Macquarie University.