Speaker
Description
To ensure reproduction, animals must efficiently detect and process intraspecific cues, such as sexual pheromones. In this study, we wonder how the brain of the honey bee, Apis mellifera, processes the unique sex pheromone described in this species, 9-oxo decanoic acid (9-ODA), which triggers male attraction to virgin queens during the mating. Previous work has shown that 9-ODA is detected by olfactory receptor AmelOR11, the most overexpressed receptor in male antennae compared to workers. We also know that this activates a specific, enlarged glomerulus in the antennal lobe, called macroglomerulus 2 (MG2). This neuronal pathway (AmelOR11 – MG2) is for now the only one described for the processing of 9-ODA within the honey bee male brain. To test whether this pathway is the only one responsible for male attraction to virgin queens, we generated AmelOR11 knock-out males using CRISPR-Cas9 genome-editing method. Mutant KO males showed an atrophied MG2 and no response to 9-ODA in their antennal lobe using in vivo calcium imaging recordings. However, associative conditioning experiments showed that mutant males could still associate 9-ODA with a sucrose reward, revealing the capacity to detect 9-ODA through another pathway. The next step is to test the attraction of AmelOR11-KO males towards 9-ODA in a behavioural assay, using a four-way olfactometer, to determine whether this pathway is the only one involved in male attraction towards virgin queens.
