# Identification of two odorant receptors tuned to alarm pheromone compounds in the honey bee Apis mellifera

## TL;DR

This study identifies two honey bee odorant receptors that detect alarm pheromone compounds, shedding light on their communication mechanisms.

## Contribution

The paper deorphanizes two honey bee odorant receptors (AmelOR136 and AmelOR109) involved in detecting alarm pheromone compounds.

## Key findings

- AmelOR136 detects alarm pheromone constituents with a sparse coding strategy.
- AmelOR109 is broadly tuned, responding to diverse odorants including pheromones.

## Abstract

Being social insects, honey bees use an array of pheromones to facilitate intraspecific communication, ensuring colony cohesion in a wide range of contexts. The honey bee represents an attractive model for studying the neurobiological basis of pheromonal processing, given that their pheromones are well characterized and their olfactory pathway has been extensively studied. Despite substantial knowledge acquired on olfactory processing in this species, the mechanism of pheromonal coding remains poorly understood. In particular, olfactory receptors (ORs) detecting social pheromones are still unknown. In this study, we used heterologous expression in the Drosophila “empty neuron system”, coupled with transcuticular calcium imaging and electrophysiology. We deorphanized two odorant receptors, AmelOR136 and AmelOR109, which detect constituents of the alarm pheromone. AmelOR136 exhibits a sparse coding strategy, suggesting a finely tuned mechanism for efficient communication in alarm situations. In contrast, AmelOR109 is a more broadly-tuned receptor, responding to diverse odorants, including pheromones.

Heterologous expression in the Drosophila empty neuron system, coupled with transcuticular calcium imaging and electrophysiology, allowed to deorphanize two odorant receptors of the honey bee which detect constituents of the alarm pheromone.