12 Nov Moving infested furniture and bed bug behaviour in direct sunlight

When moving infested furniture it is always good practice to wrap the items in plastic to ensure the bugs do not fall off in other locations. But sometimes even I cheat a bit and remove items from a suite with great care not to bump/scrape/drag the item in the building. For example I would be very confident that carefully carrying an infested cardboard box to my heating trailer could be quite safe. The bugs are deeply burrowed into the cardboard and they will not be easily dislodged. On the other hand a couch must be wrapped as it is impossible to move that item without some bumping and scraping.

A landlord I work with regularly recognizes these distinctions and also moves some items without wrapping. One day he pushed the limits a bit and moved a single (39×75) lightly infested (very little sign on the exterior) box spring without wrapping and left it on the curb for me to pick up. Personally I would not have done that without wrapping but each person has their own risk tolerance level. The rest of the furniture was wrapped because it contained more sign of bugs.

When I arrive at these “heat load” job sites I like to take a cursory look at the furniture to be loaded to see what can be learned. I did not like the unwrapped box spring but it did not appear to have much sign of bugs so I assumed it was unlikely to have caused harm. I had to wait a few minutes for the rest of the furniture to come out of the building and suddenly noticed about 20 bed bugs crawling on the surface of that unwrapped box spring. I was shocked as I had personally inspected that piece only a few minutes earlier and found little sign of bugs let alone 20 crawling bugs.

It took me a few minutes to comprehend this odd bed bug behaviour. One rarely sees bed bugs openly crawling in an untreated infested suite and to see 20 suddenly appear was amazing. Eventually I came to the conclusion that the box spring was exposed to direct sunshine (on a warm summer morning) and was being heated beyond the comfort level of the bed bugs. The increase in temperature caused the previously hidden bugs to run and the unwrapped box spring allowed them to run freely. Interestingly enough I noted the bugs were not running onto the sidewalk – they appeared to tour the entire box spring instead. For the record I hated moving that item onto my truck and I changed clothes after loading.

Later that summer I came across another similar situation. A local apartment block known for its untreated bed bugs suddenly had a severely infested box spring leaning against the exterior of the building. I took the opportunity to investigate and found the entire box spring shimmering with open bed bug activity. I will post a video of that box spring eventually. Of course I collected a few samples for experimentation purposes. The shimmering was odd as one rarely sees that much activity. The bugs are typically hiding. Once again I concluded that the direct sunshine outside was overheating the bugs causing them to run.

I investigated that box spring numerous times over the course of a day to see what could be learned. I inspected the surrounding brick work of the building frequently to see if I could see bugs crawling into the building. I never did see bugs on the building. I only found one bug on the pavement close to the box spring but that bug eventually returned to the box spring. I had expected a mass exodus into the building but I was wrong. The bugs tended to remain on the box spring. I also noted that while there were a lot of bugs crawling there were still substantial numbers in harbourages under the stapled cloth edges. Not all the bugs were moving. Interestingly I also noted that after a few hours a number of bugs had chosen to harbour on the shady back side of the box spring where it was cooler. If the bugs were looking only for harbourage there was plenty of excellent harbourage available. But instead the bugs chose the relatively open shady spot. I collected them for experimentation too as it can be difficult to find such a nice collection spot.

I was looking forward to several days of observations but unfortunately someone decided it would be a good idea to move the box spring to the neighbouring grocery store where it was leaned against their back wall. From there it fell over and was run over by a large truck and crushed. My interest waned as the experimental parameters kept widening.

The biggest things I learned here was that the bugs will uncharacteristically run all over the box spring when exposed to sunlight and actively seek out cooler areas. They would rather have an open cooler harbourage than a more preferable enclosed but warmer harbourage. Therefore moving unwrapped items on a very hot day is a bad idea – the bugs might run. I also noted that the bugs tended to remain on the box spring. I would pull out my hair with anxiety if that box spring were leaned against my own building but I never did see a bug climbing the brickwork or ever permanently move off the box spring. Unfortunately I could not do multi day observations with this experiment so the observations are incomplete.

In other settings I have noted that bugs have entered buildings from mattresses leaned against a building. It would be interesting to understand what environmental parameters were necessary for the bugs to climb into the building. Perhaps darkness would help. Or perhaps as it cooled off at night the building would exude warmth which would then attract the bed bugs.