Are odorant-binding proteins involved in odorant discrimination?

Area of Science:

• Insect olfaction
• Molecular biology
• Chemical ecology

Background:

• Pheromones are crucial for moth mating behavior.
• Pheromone-binding proteins (PBPs) are thought to play a role in odor reception.
• The specificity of PBPs across different moth species is not fully understood.

Purpose of the Study:

• To investigate the cross-reactivity of a specific pheromone-binding protein antiserum across various moth species.
• To determine if PBP cross-reactivity correlates with taxonomic or chemical relatedness of pheromones.
• To explore the role of PBPs in pheromone discrimination.

Main Methods:

• Immunolabelling of pheromone-sensitive sensilla trichodea in nine moth species.
• Utilizing an antiserum against the pheromone-binding protein of Antheraea polyphemus.
• Assessing labelling intensity in sensilla trichodea across different species and pheromone sensitivities.

Main Results:

• Strong immunolabelling was observed in some species (e.g., Saturniidae, Bombycidae, Sphingidae), particularly those using C16 pheromones.
• Weak or no labelling was found in other species (e.g., Lasiocampidae, Lymantriidae).
• Noctuidae species showed variable labelling, suggesting diverse PBPs and olfactory receptor cell specificity.

Conclusions:

• Pheromone-binding protein cross-reactivity is linked to pheromone chemical structure (e.g., C16 chain length), not just taxonomy.
• The diversity of PBPs in sensilla trichodea likely contributes to the specific discrimination of pheromones by moths.
• These findings support the role of PBPs in mediating odorant discrimination in insect olfaction.