There’s nothing quite like going outside on a dark night to watch the fireflies glowing. In addition to being beautiful, the gentle glow of the firefly is how they attract each other for mating.

While each species of firefly is unique, some of them have different glow patterns for males and females, which makes it easier for them to find each other.

According to a study from Huazhong Agricultural University in China, however, the glowing patterns are sometimes hijacked by spiders to lure in more prey.

The study got its start when its author, Xinhua Fu, noticed that orb-weaving spiders (A. ventricosus) had only male fireflies in their webs. This seemed unusual, and prompted the team of researchers to start watching more closely.

They developed a theory that suggests that the spider catches a male firefly by chance, and then manipulates it in some way to make it glow in a way that makes it appear to be a female. When other male fireflies in the area see this, they fly over with hopes of mating, only to find themselves caught in the same web.

In the paper, the process was explained in this way:

“Drawing from extensive field observations, we propose that A. ventricosus practices deceptive interspecific communication by first ensnaring firefly males in its web and then predisposing the entrapped male fireflies to broadcast bioluminescent signals that deviate from female-attracting signals typically made by A. terminalis males and instead mimic the male-attracting signals typically made by females. The outcome is that the entrapped male fireflies broadcast false signals that lure more male fireflies into the web.”

It is not yet clear how the spider is making the fireflies glow in a way that they normally wouldn’t. It could be through a venom, through biting the firefly, or some other as yet not understood process.

Behavioral ecologist, Daiqin Li from Hubei University is a co-author to the study and explained:

“While the eyes of orb-web spiders typically support limited spatial acuity, they rely more on temporal acuity rather than spatial acuity for discriminating flash signals. Upon detecting the bioluminescent signals of ensnared male fireflies, the spider deploys a specialized prey-handling procedure involving repeated wrap-bite attacks.”

This paper suggests that it is likely that there are many other examples of this type of luring going on in nature that has not yet been discovered.

It looks like the glow of fireflies is not just beautiful, but terrifying.

If you thought that was interesting, you might like to read about the mysterious “pyramids” discovered in Antarctica. What are they?