Urban spiders have seen the light – and they’re not afraid of it

ARACHNOPHOBES, beware: urban-dwelling spiders are becoming less fearful of light, scientists have found.

Most spiders prefer to build webs in dingy nooks and crannies – and it is common to see them freeze midscuttle across the floor when a room light is turned on.

But scientists gathered spiders from urban and rural locations across Europe to test whether their fear of the light was changing. They found that while spiders from the countryside still had a healthy dislike of light, those from cities were happy to build their webs in illuminated areas.

Dr Tomer Czaczkes, a biologist at the University of Regensburg, and a team of researchers at the Ludwig Maximilian University in Munich, and Aarhus University in the Netherlands gathered spider egg sacs from urban and rural locations across Germany, France, and Italy and placed the hatchlings into boxes that were exposed to light on one side and dark on the other.

“Rural spiderlings liked building their webs in the dark,” said Ana María Bastidas-urrutia, co-author of the study. “The urban spiderlings really didn’t care where they built their webs. The light didn’t seem to bother them.” The researchers, whose findings are published in the journal The Science of Nature, believe the shift in behaviour to be an evolutionary change precipitated by a search for food. Insects such as moths, which the spiders prey upon, are attracted to artificial light, making them an ideal location to build a web.

Because the spiders used in the study had not hatched, scientists are convinced that the behaviour is due to genetic changes, as they did not have the time to learn to exploit the increased prey found in light areas.