Two days ago I was called to a job site and found a relatively small infestation of bed bugs. The tenant had been away house sitting for 11 days and had recently returned and spent 4 nights sleeping in the small infestation. I started clearing a few bugs just to make the tenant feel a bit better until we could schedule treatments and noted over half the bugs i found directly on the bed had not been feeding. I found that interesting. So I questioned the tenant about the circumstances and she stated she slept with the blinds down, and had no fan. The building has no air conditioning and it has been 30 celcius plus for the last couple weeks – the room is hot. The window faced roughly south so lots of sun. The tenant also slept from 11PM to 7AM with sunrise occurring around 6AM. If changing light conditions were a factor they would have had a relatively short period to forage and feed. I don’t know if this is a factor or not – just an observation. Usinger suggested that bugs were most active just before dawn.
When I use collectabeds (inspectable cardboard all around the bed between box spring and mattress) in non chemical work i find the vast majority of the bugs are well fed. But when the tenant abandons the suite for 11 days the bugs, roughly the same distance to the host as the collectabed settings, did not feed as much. I don’t know why this pattern presented itself.
I have converted my bed bug trailers in to bed bug labs and in one experiment I attempted to emulate Richard Naylor’s method of releasing bugs on the floor of the arena and documenting their behaviour as they forage, feed, and harbour. I released 11 bugs on the floor of the lab (one extra by accident), slept in the bed that was on the lab floor for 5.5 hours, slowly raised the light levels with a dimmer switch for an hour, and exited the lab. Eight hours later I inspected the results and found all the bugs were harbouring on the floor in easily inspected harbourages and none of them had fed or harboured on the bed – interesting. I wondered if the unknown reasons for not feeding in the first story also applied here. There were some differences however, I had an air conditioning unit running that cycled on and off at 71f so there was a lot more air movement and it was far darker as well.
So I repeated the experiment without the air conditioner and had a box fan on low blowing air into the lab door (it was very hot). I thought perhaps the noise and vibration of the AC might be the source of no feeding. For the last hour I turned off the fan as well and allowed the open door to naturally cause a sunrise. Once it was full light I exited the lab and returned 8 hours later. Again zero bugs fed though they were scattered a bit more throughout the arena so I guess that is an improvement. It will take some time to figure out what is going on.
Its interesting that when I set out to answer one question I get 50 more. It seems the more I learn the less I know.