Unexpected plant odor responses in a moth pheromone system

Area of Science:

• Olfactory neuroscience
• Insect behavior
• Chemical ecology

Background:

• Male moths use olfactory cues for reproduction and foraging.
• Pheromone and volatile plant compound (VPC) detection pathways were thought to be separate.
• Recent evidence suggests interactions between pheromone and VPC processing.

Purpose of the Study:

• To investigate the overlap in detection and processing of VPCs and sex pheromones in male moths.
• To determine if plant odorants can activate pheromone-specific olfactory pathways.

Main Methods:

• Single-sensillum recordings of olfactory receptor neurons.
• In vivo calcium imaging in the antennal lobe.
• Intracellular recordings in the macroglomerular complex (MGC).
• Flight tracking in a wind tunnel.

Main Results:

• The plant odorant heptanal activated the pheromone-specific pathway in male Agrotis ipsilon.
• Activation occurred at both peripheral and central levels of the olfactory system.
• This represents the first report of a plant odorant acting as a partial agonist of a moth sex pheromone without structural similarity.

Conclusions:

• Detection and processing of VPCs and sex pheromones can overlap in male moths.
• Plant odorants can influence pheromone-driven behaviors, impacting mate-finding and habitat selection.
• This interaction challenges previous assumptions about segregated olfactory subsystems.