Morphological correlates of differences in pheromone sensitivity in insect sensilla

Area of Science:

• Entomology
• Neurobiology
• Sensory Neuroscience

Background:

• Male moths detect female sex pheromones using specialized olfactory sensilla on their antennae.
• Understanding the structure-function relationships of these sensilla is crucial for insect communication research.

Purpose of the Study:

• To investigate the different classes of pheromone-sensitive sensilla trichodea in male *Trichoplusia ni*.
• To characterize the neuronal responses within these sensilla to a key sex pheromone component.

Main Methods:

• Utilized scanning electron microscopy to visualize antennal sensilla.
• Employed single unit recordings to measure neuronal activity in response to pheromone stimuli.

Main Results:

• Identified at least two distinct classes of sensilla trichodea.
• Longer sensilla contained two receptor neurons, one responding to high doses (10 µg) of (Z)-7-dodecenyl acetate.
• Shorter sensilla housed two neurons with higher spontaneous activity and sensitivity to low doses (0.01 µg) of the pheromone.

Conclusions:

• The *Trichoplusia ni* male antenna possesses functionally distinct pheromone-sensing sensilla.
• Differential neuronal properties within these sensilla contribute to the detection of varying pheromone concentrations.