Spider Tricks Fireflies With Mysterious Death Trap

Spider-gazing researchers in China say that the orb-weaving spider (Araneus ventricosus) entices male fireflies into its web, then it gets freaky.

Somehow the spider manipulates its prey into mimicking a female firefly’s flashing light, which lures more amorous males into the deathtrap.

Fireflies famously use their illuminated abdomens to find and attract mates. In the species Abscondita terminalis, males make multi-pulse flashes using their two lanterns to attract females, while females make single-pulse flashes with their single lamp. The researchers observed that males trapped in the web begin single-pulse flashing like a girl, especially when the spider is nearby.

Other males, mistaking the altered light show for a mate, fly into the honey trap and to their doom. The scientists don’t know exactly how the orb spider casts this insidious spell, but they think it has something to do with how it wraps and bites its prey.

“We propose that in response to seeing the ensnared male fireflies’ bioluminescent signals, the spider deployed a specialized prey handling procedure based on repeated wrap-bite attacks,” the team writes. 

“We also hypothesize that the male firefly’s neurotransmitters may generate a female-like flashing pattern. For determining whether it is the spider’s venom or its act of biting that exerts the manipulating effect on flashing, further research is needed.”

The new research appears in the journal Current Biology. The lead authors are all from Wuhan, where there’s little chance an animal-borne hazard (like spider venom) could ever leak from the lab.

Photo credit: Xinhua Fu