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On the Trail of Bed Bugs

Continuing our recent discussion of bedbugs, we offer an interesting recent study on the movement of those notorious insects. Despite considerable research in recent years, certain behaviors of the bed bug remain poorly understood. While their movement between apartments in a multiplex has long been suspected, it has never been empirically proven. However, a research article published last month by Richard Cooper, Changlu Wang and Narinderpal Singh offers valuable insight into the movements of these creatures, as well as about other behaviors that will aid in future remediation.

As published in their report, Mark-Release-Recapture Reveals Extensive Movement of Bed Bugs (Cimex lectularius L.) within and between Apartments, Cooper et al conclusively demonstrate the active migration of bed bugs between units. Even when a single infected unit is occupied by a so-called “host,” meaning you and me, the insects are shown to move to adjacent units and not only by “hitchhiking” on luggage or other objects as commonly understood, but actively and directly, on foot—through ceilings, floors, walls and down hallways.

The research was conducted in bed bug-infested apartments located in affordable housing communities in three cities in New Jersey: Irvington, Hackensack, and Newark. The apartments, which represented both concrete block and wood frame construction, were not cluttered, had little furniture and had not been treated for bed bugs prior to the experiment.

During the study, bed bugs, both nymphs and adults, were collected from each apartment over a two-day period. Some were marked with a single drop of paint. Others were left unmarked, and then all were released again in the apartment from which they had been collected. “Pitfall” type interceptor traps were set in each apartment and samples were collected ongoingly for several weeks.

A number of interesting discoveries resulted. First, in apartments where bugs had been released directly on the furniture the occupant used for sleeping, between 38 and 67% of the bugs recovered were more than six feet from that original location. In every case, bed bugs from a particular site were collected in neighboring apartments as well, and not necessarily adjacent to the original site. In every case, the majority of the insects collected were female adults. One of the apartments in the study was vacant, providing researchers with an opportunity to determine how long starved bugs could survive, or at what point they might abandon the location. The results? Younger nymphs were no longer in evidence after 134 days. But when the experiment was concluded after 155 days, large nymphs and adults were collected in the apartment even without a “host.”

From these observations, researchers concluded that bed bugs are very mobile and travel extensively throughout apartments in a multi-unit building, that they have the ability to disperse from occupied and vacant apartments to neighboring apartments, and that they can survive as much as five months without a blood meal.

These findings have implications for practices that result in successful remediation. Clearly, it isn’t practical to starve out an infestation. These creatures can be very patient and resilient. Also, no longer should it be assumed that bed bugs live primarily in furniture near the sleeping area of a host, and remain in that area unless allowed to hitchhike to a new location. Observations that bed bugs can travel easily on their own and are inclined to do so, even in the presence of an available host, indicate a need to inspect and possibly treat more than the area of first discovery of any infestation. Surrounding units, even those significantly removed from the initial site, should also be assumed to potentially harbor these insects.

Curiously, the movement of females at greater rates is not yet sufficiently understood. Among several theories is the suggestion that females may try to escape repeated insemination by males, and so “flee” to nearby apartments. Males may follow in search of these females. That determination may come in time. For now, we have enough to “digest.”

This study supports practices already in effect at ATCO, and we will continue to monitor research so as to better serve our clients for all their pest management needs. Diamond Certified and ECO-wise certified, ATCO is your local resource for research-based remediation.