Bedbugs prefer dirty clothes
by Dr. Micheal R. Linford
January 17, 2018
A recent study published by Nature reports that bed bugs are more attracted to dirty laundry than clean clothing, and help us to better understand how and why bed bugs move around an infested area. This knowledge allows us to target locations and utilize temperature probing to ensure thermal efficacy.
From the study’s abstract: “Bed bugs have shown a recent and rapid global expansion that has been suggested to be caused by cheap air travel. How a small, flightless and anachoretic insect that hides within its host’s sleeping area manages to travel long distances is not yet clear. Bed bugs are attracted to the odour of sleeping humans and we suggest that soiled clothing may present a similarly attractive cue, allowing bed bugs to ‘hitch-hike’ around the world after aggregating in the laundry bags of travellers. We show that (1) soiled clothing is significantly more attractive than clean clothing to active bed bugs moving within a bedroom sized arena and (2) elevation of CO2 to a level that simulates human occupancy in the same arena appears to initiate search behaviour rather than direct it. Our results show, for the first time, how leaving worn clothing exposed in sleeping areas when travelling can be exploited by bed bugs to facilitate passive dispersal.”
The study reports a significant interaction between levels of CO2 released by a living target and the distribution of bed bugs within a treatment area. In the presence of elevated CO2 more bed bugs left their harborages with nearly insignificant numbers of the insects remaining in the refuge. By contrast, approximately a quarter of the bedbugs were found in the refuge at the end of the experiment. The extra dispersing individuals under elevated CO2 were not found aggregating on clothing, but were found on the floor within the treatment area such as adjacent to the area perimeter or, on three occasions, the open floor area, most likely moving between the target of the blood meal and remote harborages.
This study drives home the significance of understanding bed bug activity, finding harborages and safe zones, and treating the entire treatment area. The report also infers the importance of temperature measurement in the hardest-to-heat locations in the treatment area, since this is often where the insects can be found when not seeking a blood meal.
From the report: “Our results do show that bags containing soiled clothes were significantly more attractive to bed bugs than identical bags containing clean clothes. Human odour is a known cue for host-seeking bed bugs, but until now studies have focussed on how these cues determine the attractiveness of a sleeping host. Our results show that bed bugs will move to, and aggregate on, soiled clothing in the absence of a host. Bed bugs can sense 104 different volatiles16 found in the odorant profile of human skin. Many of these volatiles are likely to evaporate from ‘soiled’ clothes for some time after they have been worn, removed and/or stored.”
GreenTech Heat suggests removing clutter from a treatment zone. Any clothing removed from a treatment area should be processed through a hot wash followed by a dry cycle for a minimum of one hour at high heat. Items that cannot be washed and dried should be bagged and placed in the freezer overnight.
I've been safely eradicating bed bugs and other insects with heat for nearly 30 years. I appreciate clinical studies like this one that extend our understanding of these pests and better our abilities to rid them from our lives.