We learned earlier with Richard Naylor’s observations that bed bugs move further away from the host when harbourage near the bed is restricted. We have seen this in practice in the field many many times. For example, if a tenant is sleeping on a mattress directly on the floor the mattress ribbing is covered with a bed sheet which results in poor bed bug harbourage on the bed. The bed bugs then avoid the bed and harbour in the nearest area that does have harbourage such as dressers, door frames, clothing, etc. Conversely a nice mattress with a box spring and frame with legs tends to concentrate the bugs in the box spring with fewer bugs off the bed. Therefore there are fewer bugs in the dressers and door frames. This is why I always recommend people have a nice bed with box spring and legs – if an infestation occurs the bugs tend to remain concentrated on the box spring which in turn makes other items in the bedroom less likely to be infested. If back packs and clothing are not infested the potential for infestation outside the home is reduced.
We also learned that some bed bugs will wait for a host for several months on a mattress if the host abandons the suite – even if there a person is living in the next room 10 feet away. We see the same behaviour in severe infestations with the bugs slowly leaking out of the walls for several months to the great frustration of all involved. The bugs have been pushed far enough away from the host that they can not ascertain host cues causing the bugs to hide in their harbourages almost indefinitely. And when they do emerge it is possible the bugs will simply move to the next suite instead of accessing the original host which causes even more harm.
Modern bed bug policy revolves around the idea that bed bugs on the bed are bad and the bugs should be kept off the bed. In Manitoba this idea is expressed in mattress encasements being given away for free (on tax payer dime) to people who can not afford them. The result is that the bed has very poor harbourage and the bugs are forced to harbour further away from the host off the bed. And if the bugs move far enough away from the host there is a danger that they will lose track of the host and wait long periods of time for host cues. The result is the suite becomes very difficult to treat when the bugs do not cross the residuals the exterminator uses. And if the bugs have been pushed to areas that the exterminator can not access (inside a wall cavity) the prognosis for that suite is poor.
Therefore it is imperative that bed bugs be given ample opportunity to harbour on or near the bed. Any attempt to keep bugs off the bed results in bugs harbouring further away from the host and increases likelihood that the bugs will begin waiting for host cues that can not be discerned. The difficulty for the exterminator is therefore multiplied many times. Preemptive mattress encasements are a direct shot to the public policy foot.