What are bed bug kairomones? The science behind ExHale
By Skatek · · 2 min read
Bed bugs are hard to find, and passive monitors often miss them. The reason is kairomones. Once you understand what they are and how bed bugs use them, you can make bed bugs come to you instead of waiting for them. That is the idea behind ExHale.
What is a kairomone?
A kairomone is a chemical signal from one organism that helps the one receiving it, not the one sending it. For bed bugs, the strongest kairomone is carbon dioxide, the gas we breathe out. A sleeping person gives off a steady plume of CO₂, and bed bugs follow it to find their host. They also respond to body heat and to compounds from human skin. Together, these signals tell a bed bug that a person is asleep nearby, and bed bugs have evolved to follow them.
Researchers have tested these cues one by one and together. CO₂ draws bed bugs on its own, and adding heat or a chemical lure changes how strongly they respond (Singh et al. 2012).
Why this matters for monitoring
A passive monitor sits on the floor and waits for a bed bug to walk into it by chance. That works, but it is slow, and it misses infestations early on, when there are few bugs and they rarely leave their hiding places. That is when you most want to find them.
Using kairomones turns this around. When you release CO₂ and the compounds of a sleeping person, the room reads as occupied, and bed bugs come out of hiding. In one field study, CO₂ traps left overnight found 125% more bed bugs than a visual inspection alone (Wang et al. 2009). You find them sooner and get a clearer picture of where they are, even in rooms that looked clear.
How ExHale uses this
ExHale recreates the kairomone profile of a sleeping person. The aerosol releases CO₂ and human-scent compounds, and the programmable dispenser releases it on the schedule the technician sets. The room seems occupied whether or not anyone is in it. ExHale works with the bed bug's own biology. It is a monitoring tool, used before treatment to find bed bugs and after treatment to check that they are gone.
What the tests show
Two independent tests for Skatek looked at ExHale on live bed bugs. At the University of California, Riverside, Dong-Hwan Choe found that about twice as many bed bugs left their hiding place on the night ExHale ran, while the control group stayed about the same. In a bedroom study in the UK, Dr. Richard Naylor found ExHale effective at activating bed bugs in a simulated infestation.