Characterizing the Responses of Antennal Olfactory Sensilla of Bed Bugs, Cimex lectularius, to Components of Aggregation Pheromone

Abstract

Responding to urgent call for detecting and monitoring tools of bed bugs, rapid resurgence of which has been noticed by many developed countries recently, aggregation pheromones have been considered as a promising baits for monitor all developmental stages of bed bugs. This study addressed questions concerning how the signals of aggregation pheromones were encoded by olfactory sensilla of the bed bug, Cimex lectularius. From broadly tuned spectra of D sensilla with high sensitivity to aggregation pheromone, to narrowly tuned C sensilla, the overall encoding map of sensilla for aggregation pheromone revealed strong responses of odorant-sensillum combinations without showing sexual dimorphism. Majority of sensilla that were well developed in nymph bed bugs generally showed similar response patterns to our odorants panel, except for early instar nymph stages (1st and 2nd), which exhibited significant lower neuronal activity for S-(-)-limonene and R-(+)-limonene compared to 5th nymph and adult stages. We finally tested the olfactory response patterns of the most abundant sensilla, hair-like sensilla, with stimuli from different components of an aggregation pheromone as well as human odorants. Our results revealed 4 distinct functional classes of hair-like sensilla.