What’s a bedbug’s favorite color?
New research shows that the pests prefer to take shelter in black and red materials, while they are generally repulsed by colors such as green, yellow and white.
A study published April 25 in the Journal of Medical Entomology found that bedbugs’ color preferences develop as the insects age. Young bedbugs don’t have very developed eyes and don’t seem to have very distinct color preferences, says study first author Corraine McNeill, an entomologist at Union College in Lincoln, Nebraska. However, the closer they get to adulthood, the more and more they seem to prefer red and black, she says.
The scientists speculate that bedbugs prefer black because it is representative of darkness, which they naturally seek; after all, they’re mostly nocturnal bugs that hide in corners of mattresses and other crevices before coming out to feed on the blood of people or other animals, McNeill says.
But why red? “It’s probably not because it’s the same color as blood,” McNeill says. When they feed, bedbugs are guided by cues like temperature and the release of carbon dioxide, but they can’t actually see the blood itself. McNeill theorizes that the insects prefer this hue because they have a reddish exoskeleton, so this color suggests the presence of other bedbugs.
Like many other insects, these blood-suckers make a habit of gathering in aggregations. In the case of bedbugs, gathering helps young bedbugs mate more easily; it also enables them to stay better hydrated since groups retain more moisture, McNeill says.
As to why bedbugs don’t like green, yellow and white, the scientists say that these colors are generally found in well-lit, exposed areas—exactly the opposite of the type of environment where the insects like to hang out.
But she doesn’t advise people to throw out their red or dark-colored sheets just yet. Since bedbugs typically shelter in dark areas and seek blood through cues unrelated to color, it’s not likely that changing your linens would make a difference in protecting yourself from infestation. However, the study’s finding could be used to design better traps, which are used to verify the insects’ presence. Many traps used to date have been white, which “is exactly the opposite of what you’d want,” based on the bugs’ color preference, McNeill says.