Observations of bed bug behaviour in light versus dark versus almost dark settings.

I collected more than 100 bed bugs from a mattress in the alley and decided it was time to test some non-glueboard bed bug traps. I had four ordinary traps and two were modified slightly to see if they would perform better. The traps were set in a diagonal pattern to elicit fairness. The top of the experiment was covered so the experiment tank was in an even shade. This would be similar to the amount of light under a bed if the light was on in the room.


The first experiment in the “light” showed that my new modified trap caught almost twice as many bugs as the unmodified trap. The modified traps caught 16 plus 18 while the unmodified caught 9 each. Pretty even set up I thought.


I then turned off the light but left the door open ¾ of an inch to allow a little bit of light from the hallway. The room was too dark for me to see but it was not pitch black. This time both traps furthest from the door (one modified and one unmodified) caught few bugs while the two traps closer to the door caught far more. The modified trap that was closest to the light coming from the door that was open a crack caught the lions share of the bugs. Interesting.


I performed 3 more similar experiments making the room darker and darker. I closed the door entirely for two experiments and the last one had the door closed with a towel under the door to block light from that avenue. In all three cases both traps closest the door (one modified and one unmodified) together caught roughly twice as many bugs as the other side. The total results for comparing the traps were all over the map with no distinct winner or loser.


I found it interesting that the traps closest to a very dim light source in a mostly pitch black room caught at least twice as many bugs as the traps one foot further away toward the dark while a “lighted” arena had an even distribution. Do bed bugs use a minimum amount of light for navigating? If someone has experience in this matter please email. I would love to learn more.


It is also interesting that trapping behaviour is different in light conditions versus dark conditions. In “lighted” settings the modified traps were roughly twice as effective as the unmodified trap. In dark conditions the results were much more muddled. For example in the last test the two traps closest to the door had 10 bugs in the modified trap versus 7 for the unmodified.


Bed bugs are complicated.




Previous Post

Homeless shelters are vectors for bed bug dispersal

Next Post

Is your dryer adequate to kill bed bugs?