Profiling Volatile Terpenoids from Calabrian Pine Stands Infested by the Pine Processionary Moth.

Area of Science:

• Plant biochemistry and chemical ecology
• Forest entomology and plant-insect interactions

Background:

• Terpenoids are a vast class of plant compounds (over 40,000 identified).
• In conifers, terpenoids are crucial for defense against pathogens and herbivores.
• The pine processionary moth (Thaumetopoea pityocampa) is a significant pest of pines.

Purpose of the Study:

• To investigate the terpenoid defensive responses of Calabrian pine (Pinus nigra subsp. laricio) to pine processionary moth infestation.
• To identify specific volatile terpenoids associated with herbivore attack in a natural setting.

Main Methods:

• Field study on adult Calabrian pine individuals at two distinct forest sites.
• Monitoring of volatile terpenoids emitted from pine needles during caterpillar infestation.
• Correlation analysis between terpenoid emissions and the stages of caterpillar feeding activity (defoliation).

Main Results:

• Bornyl acetate was the most frequently and selectively detected volatile terpenoid associated with pine processionary moth infestation.
• Bornyl acetate emissions increased significantly during peak caterpillar feeding (defoliation) and decreased afterward.
• The observed volatile terpenoid changes suggest a role in plant defense or inter-plant communication.

Conclusions:

• Bornyl acetate is a key volatile terpenoid linked to Calabrian pine's response to pine processionary moth herbivory.
• These findings support the growing interest in plant secondary metabolites for pest control strategies.
• Further research is needed to fully elucidate the defensive and communicative roles of these terpenoids.