Researchers at Simon Fraser University have just published a paper describing a bedbug pheromone blend which includes three new volatiles and a surprising arrestant: histamine!
Regine Gries, along with colleagues from SFU’s Chemistry and Biological Sciences Departments have been working on pheromone chemistry of these pervasive and damaging pests for years. Regine has led the effort, maintaining bedbug colonies and devising many ways of extracting and testing the compounds. By analysing headpace volatiles of bedbug-soiled paper, they were able to identify three new volatile pheromone components: dimethyl disulphide, dimethyl trisulfide and 2-hexanone. These, in addition to the previously-identified alarm pheromone components (E)-2-hexenal and (E)-2-octenal, attract bed bugs to experimental shelter baits placed in study arenas.
The identification of histamine as an arrestant pheromone is quite novel, as this compound is not volatile at all. The free base of this common amine hormone is present in bed bug exuviae, and when applied to paper shelters causes bed bugs to remain in place. Bed bugs seem to use histamine as a signal that the shelter is a safe resting site. This is so effective, that experimental traps with only histamine catch more bedbugs than traps coated with the traditional sticky trap coating. Bed bugs are so reluctant to leave the traps with histamine that they remain in place even when the trap is picked up.
These findings will likely translate into more effective monitoring and control tools for these difficult-to-eradicate pests.