Animals Cunning trick: spider uses prey to attract more prey

Nasty, nastier, Araneus ventricosus: The spider doesn't just eat its prey. It first uses them to attract more victims - with special flashes of light.

A species of spider uses the flashing signals of captured fireflies to attract even more of the insects. It manipulates the light flashes of certain male fireflies caught in its web in such a way that they imitate the typical flashing signals of a female firefly and attract more males, as a research team reports in the journal "Current Biology".

Fireflies communicate via flashing signals that they emit with transparent areas of their abdomen. In the species Abscondita terminalis, the males produce multiple flashes with two transparent fields to attract females, while the females produce single flashes with one field to attract males.

More males in the web

The researchers led by Daiqin Li from Hubei University in Wuhan had noticed that there were hardly any female fireflies in the webs of the spider species Araneus ventricosus in nature. They then observed what was happening more closely.

First of all, they noticed that male fireflies of the species Abscondita terminalis were more likely to hang in the web when the spider was present. In addition, they noticed that the signals of such hanging males were much more similar to the signals of females than those of other males: they sent single-pulse signals from only one of the transparent areas.

Trickery makes you richer

The catch rate in such nets was significantly higher, according to the study. The researchers suspect that the spiders deliberately alter the fireflies' signal. It is unclear whether the spider's venom or the bite itself leads to the changes in the flashing pattern.

Spiders were already known to leave the remains of previously caught prey in their webs, which then act as bait for other insects. Daiqin Li's team speculates that there could be many more examples of predators manipulating the behavior of their prey to their own advantage.

Fireflies do not glow

Incidentally, the name glowworm is misleading: they are beetles - and they do not glow, i.e. they do not get hot when they glow. Physically, the light is produced in a similar way to an LED. In the case of LEDs, however, the energy source is electric current, whereas in the case of fireflies it is chemical reactions.

Fireflies attract mates with their glow. There are species in which only the females glow, while in others the males also glow.