"We originally thought the bedbugs might prefer red because blood is red and that's what they feed on," study co-author Corraine McNeill, an assistant professor of biology at Union College in Lincoln, Nebraska, said in a statement. "However, after doing the study, the main reason we think they preferred red colors is because bedbugs themselves appear red, so they go to these harborages because they want to be with other bedbugs, as they are known to exist in aggregations."
Unlike those of other insects, bed bug bites may sometimes appear in tight lines of multiple, small, red marks where multiple bed bugs have fed along an exposed area. Bed bug bites can cause itchiness. Initially, a victim may detect a slight burning sensation. The burning area then develops red bumps, known as papules or wheals (rash). In extreme cases, bites may swell dramatically or turn into blister-like skin inflammations.