One of my landlord customers has been monitoring a large building and one of the suites contained zero furniture except for a very small stuffed chair and a thin area carpet. The scant furniture and lack of obvious sleeping area created problems for monitoring so random flat trapper max glue boards were placed in the corners of the main area. Upon later inspection it turned out some of these glue boards contained up to 149 first instar bed bugs with a small number of second instars. The glue boards were replaced and, while treatment was being scheduled, the glue boards were again inspected with similar findings – lots of baby bugs but no larger bugs.
In a different building a tenant was sleeping on a single mattress on the floor and we asked the tenant to get a bed frame so we could use the modified glue board traps (carpet version on carpet). The tenant failed to comply and the traps were simply placed against the wall near the mattress. When we returned two weeks later we noted the non compliance and also discovered the modified glue board traps were filled with all stages of bed bugs spanning first instar through adult. I found the difference in catch rates between the modified and unmodified glue boards interesting.
In the lab I noted that unmodified glue boads performed poorly (repellency) while the modified version worked excellently. I also noted in my experiments with double sided sticky tape that the first instars were much easier to trap while the larger bugs could escape easily. My first thought upon seeing the above comparison was that the unmodified glue board was able to catch the smaller bugs but failed with the larger more energetic bugs. The modified glue boards in the second suite caught all stages as would be expected.
Unfortunately the above theory, though nice and neat, is not complete. We have noted that regular unmodifed glue boards, despite the poor lab results, when used on hard floors under bed legs do in fact catch large numbers of bigger bugs. Even the random triangle glue board monitors, while very inefficient, do catch the occassional large bug.
I have learned over the years to hold apparent contradictions in tension and allow field observations and lab results to stand. Perhaps there is a piece of information missing that will bring all the pieces together. Having said that I still use and recommend the modified glue board. They just work – both in the lab and the field.