Insects and fluorescent lights

It’s wasp season once again, and the little beasts once again find their way into my home, searching for food, or so I’m told. Funny thing, though; they like to crawl on one place they are guaranteed to find nothing edible - namely fluorescent lights.

So what’s going on? Are the miniature monsters just attracted to light, but repelled by the heat of incandescents? Or does something about light from the fluorescent tubes mess with their tiny little brains and draw them in?

Here’s a recent thread on the attraction of insects to light.

Different kinds of insects are attracted to different wavelengths of light. Therefore it is possible that wasps are preferentially attracted to fluorescent lights instead of incandescent because of differences in the wavelengths they emit. I suspect this is the most likely explanation. It is, however, possible that they are just more noticeable around the flourescents because they are able to stay closer to them.

Wasps, like most insects, are sensitive to yellow through ultraviolet wavelengths of light. Incandescent lamps emit mostly in the red and infrared, and therefore look brighter to our eyes than to most insects. Fluorescent lamps, OTOH, emit primarily in the yellow and blue/violet regions of the spectrum (except for these new tri-phosphor lamps that emit mostly separate red, green, and blue/violet wavelengths… I don’t know which kind you have around). So fluorescent lamps typically look brighter to them than incandescents do.

And I just wonder what effect the hum of the lamp has on insect behavior? Could that be an attractant? Maybe it’s the wasp equivalent of “Hey, big boy, come on over here.”

Back in my entomological study days, we used to collect night-flying insects by taking Black Lights (Ultra-Violet light sources), powered by gas generators, out to the wilderness. Once fired up and the light reflected off of a white shee, every damn insect for miles would come roaring in! They are highly attracted to the violet end of the spectrum. The flourescents put out more light in the violet spectrum than incandescents, so the insects are more strongly attracted to that light source.