Much like us, bed bugs have favourite colour schemes when it comes to their homes, research shows.
Biologists from the US, led by Corraine McNeill from Union College in Nebraska, found red and black their favourite shades, while yellow and green seemed to be the colours least liked.
Because bed bugs (Cimex lectularius) spend around 90% of their time in their homes, with the rest spent seeking hosts or finding new shelter, understanding their housing preferences lets exterminators design more effective traps.
The study set-up was quite simple: researchers folded tiny tents using different coloured cardboard and arranged them in a petri dish. Bed bugs were then placed in the dish, in the middle of the rainbow city, and given 10 minutes to decide on their preferred lodgings.
They tested bed bugs of varying ages, sexes and levels of hunger, as well as bed bugs in groups and on solo missions. And while red and black were generally a bed bug’s preferred colours, green and yellow tended to be avoided.
Interestingly, the bed bugs’ preferred colours shifted with their age, hunger levels and between the sexes. For instance, a well-fed bed bug is very choosy about house colour, and prefers an orange or violet hiding hole, while a hungrier bug is less particular – perhaps due to hormonal changes that occur after feeding.
The reason for overall red and black preferences, though, had little to do with mood or feng shui, and more to do with light or dark. According to the study, it’s unclear whether bed bugs can actually differentiate between red and black – perhaps they prefer them both for their apparent darkness.
Another possible reason for their love of red, the researchers say, is the fact that they generally travel in packs.
“We originally thought the bed bugs might prefer red because blood is red and that’s what they feed on,” says McNeill.
“However, after doing the study, the main reason we think they preferred red colours is because bed bugs themselves appear red, so they go to these [tents] because they want to be with other bed bugs.”
The reason behind the bugs’ aversion to green and yellow may be that these colours more closely resemble well-lit areas.
Importantly, McNeill says the findings, published this week in the Journal of Medical Entomology, aren’t strong enough to warrant throwing out red and black bed sheets.
Rather, the colour preferences can be used in addition to other control methods, and particularly in established traps.