Q: Are spider webs passive, or do...

Q: Are spider webs passive, or do they do something to attract insects?

A: Researchers long thought that they were simply passive traps for unwary insects, but recent findings suggest that the webs actually lure their prey, which can confuse it with a plant. Many plants reflect invisible ultraviolet light off their flowers. These so-called floral guides or nectar guides attract some pollinating insects “like airstrip landing lights,” said biologist Gary Polis of Vanderbilt University. Some webs, like that of the orb spider, also reflect ultraviolet light, and careless insects are lured into them thinking they are a flower.