# Human Odorant Reception in the Common Bed Bug, Cimex lectularius

## TL;DR

This study explores how bed bugs detect human odors, identifying specific odorants that trigger their host-seeking behavior.

## Contribution

The study identifies specific odorant receptors and their responses to human aldehydes, offering new targets for bed bug control.

## Key findings

- D-type olfactory sensilla are primarily responsible for detecting human odorants in bed bugs.
- Aldehydes and alcohols elicit strong neuronal responses, while carboxylic acids do not.
- Two bed bug odorant receptors show specific responses to aldehyde-based human odorants.

## Abstract

The common bed bug Cimex lectularius is a temporary ectoparasite on humans and currently resurgent in many developed countries. The ability of bed bugs to detect human odorants in the environment is critical for their host-seeking behavior. This study deciphered the chemical basis of host detection by investigating the neuronal response of olfactory sensilla to 104 human odorants using single sensillum recording and characterized the electro-physiological responses of bed bug odorant receptors to human odorants with the Xenopus expression system. The results showed that the D type of olfactory sensilla play a predominant role in detecting the human odorants tested. Different human odorants elicited different neuronal responses with different firing frequencies and temporal dynamics. Particularly, aldehydes and alcohols are the most effective stimuli in triggering strong response while none of the carboxylic acids showed a strong stimulation. Functional characterization of two bed bug odorant receptors and co-receptors in response to human odorants revealed their specific responses to the aldehyde human odorants. Taken together, the findings of this study not only provide exciting new insights into the human odorant detection of bed bugs, but also offer valuable information for developing new reagents (attractants or repellents) for the bed bug control.