Blood-sucking bed bugs prefer red and black and are repelled by yellow and green

Bed bugs have colour preferences, researchers have discovered. An experiment has shown how they are drawn to red and black and have an aversion to green and yellow, a find that could help scientists develop better ways to control these parasitic insects.

The discovery came about after Phil Koehler, from the University of Florida, noticed there had been little research into bed bug vision and their response to colour. Initially, fellow researcher Corraine McNeill, from Union College in Lincoln, was sceptical, but initial tests revealed the bed bugs were attracted towards certain colours.

In their study, published in the Journal of Medical Entomology, the scientists set up small tent-like shelters, made from different colours of card, and placed them in a petri dish. A bed bug was then placed into the dish and given ten minutes to choose a coloured shelter.

Findings showed that although colour preference changed slightly with age, sex and hunger level, the bugs showed a strong preference for red and black, followed by orange. They also showed an aversion to yellow and green.

McNeill said: "We originally thought the bed bugs might prefer red because blood is red and that's what they feed on. However, after doing the study, the main reason we think they preferred red colors is because bed bugs themselves appear red, so they go to these harborages because they want to be with other bed bugs, as they are known to exist in aggregations."

The scientists also said they think bed bugs might avoid green and yellow because they resemble brightly lit areas - "contrary to the nocturnal habits of these insects", the study said.

They hope the results can be used to find new ways to control bed bugs: "Unattractive visual colours, such as yellow and green, should be taken into consideration in the development of monitoring tools or traps for bed bugs."

While the authors do not suggest people change their bed sheets based on their findings, the idea cannot be dismissed altogether:"I always joke with people, 'Make sure you get yellow sheets!', but to be very honest, I think that would be stretching the results a little too much," McNeill said. "I don't know how far I would go to say don't get a red suitcase or red sheets, but the research hasn't been done yet, so we can't really rule that out completely."