Can You See Spiders With a Black Light?
WouterIf you can’t get a good look at spiders with your eyes, it’s easy to spot them with a flashlight. The wolf spider, for instance, can be easily seen by torchlight. It also isn’t always venomous.
Although a number of insects can be detected by a black light, spiders are not one of them. They have very small eyes, usually eight, and their vision is not the best. Still, they can often be found in fields and pastures. In fact, some prefer to hide in the corner of a house.
To get a better look, sweep your light over a patch of grass about fifteen feet away. You’ll be able to see a few different types of spiders. For example, the wolf spider is usually a brownish-gray color. Some species are shaped like peanuts.
Another type of spider is the jumping spider. These creatures have three color channels in their eyes, with each channel having two pigments that filter UV and green light. During daylight, they can also see ultraviolet, but in the dark, they are virtually colorless.
Scientists at the National University of Singapore recently discovered that male jumping spiders can use UVB light as a signal. This opens a new field of research. Their success rate in courting was drastically reduced when they were not exposed to UVB.
Female jumping spiders also have the ability to fluoresce under ultraviolet illumination. Previously, it was thought that these spiders used UV reflectance to attract a mate. But the scientists discovered that they actually vibrate their palps in response to UV light.
