The available research shows that bed bugs are unlikely to follow Co2 cues beyond 5 feet. Heat has been shown to attract within one foot. Various smells that humans emit also attract bed bugs but have much less potency than Co2. But in my practice I have found that bed bugs can sometimes find a host at 25 feet. How do we explain that discrepancy?
One theory is that bed bugs follow scent trails like an ant follows pheromones. My thinking was that bedbugs, when laden with blood, are very tail heavy and drag themselves over the ground. Perhaps they leave a scent trail unwittingly which could be followed?
But this theory was proven incorrect in Richard Naylor’s experiment documented in his PhD thesis entitled “ Ecology and the dispersal of the Bed bug”. An interesting side observation in this experiment was that bed bugs more than 50 cm away from the Co2 host did not feed as often as those that were closer. The Co2 did elicit a feeding response (became active) but they did not find the host. Naylor did suggest that a relatively breezy experiment room may have played a part in dispersing the Co2 so that the bugs could not home in on the source. But if the bugs were able to follow a scent trail the bugs located beyond 50cm from the Co2 source source would have found the food source – they they did not. This disproves the theory that bed bugs follow scent trails.