MadSci Network: Environment & Ecology |
Insects are not totally colorblind. Experiments with bees and others have shown that they have sensitivities in the green and UV, but vary in their sensitivity to red. However we must not assume that what we see is what the insect sees! A red light may attract certain types of insects, but not others. While blue (which we might assume would attract more) may attract less. It is in fact likely that the insect may see a totally different "color" than we do when looking at the same light. Most insect collectors use a light that produces a fair amount of UV and this seems to draw most (but not all) insects. A simple experiment (best done during summer) is to set out different colored plastic party bowls - blue, yellow and red. Each is set to trap insects with the bowl half full of water to which a drop of detergent has been added. Bees tend to show up at blue bowls, parasitic wasps to yellow and often butterflies to red, although red tends to have fewer visitors than the rest. Oddly insects collected in this way make very good specimens- even the butterflies! Keep in mind that these catch day-flying insects, while lights attract night-flying insects. As to your experiment, I don't think that you can be sure what the insect is seeing [they do not see with antennae (although these may be sensitive to heat), but with their compound, and sometimes simple, eyes.] You can only report a statistical average for each light and then try to explain the result. It may help if you can at least sort the insects to order, as different insects have different sensitivities (not all insects are equal in their reaction to a given light). You may find a very interesting pattern. It is a bit of a difficult time to get insects to come to lights, unless you live in Florida, Hawaii or some tropical part of the planet, or the Southern Hemisphere. A possible reference is: Wigglesworth, V. B. 1964. The Life of Insects. The World Publishing Company, Cleveland, Ohio, 360 p., especially chapter 11, Insect Vision. You might also try the Internet for more information.
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