Olfactory Cues from Pathogenic Fungus Affect the Direction of Motion of Termites, Coptotermes formosanus

Area of Science:

• Entomology
• Chemical Ecology
• Behavioral Ecology

Background:

• Formosan subterranean termites (Coptotermes formosanus) exhibit complex social behaviors, including pathogen avoidance and grooming of affected nestmates.
• Understanding termite responses to microbial threats is crucial for pest management and social insect biology.

Purpose of the Study:

• To investigate the behavioral responses of Formosan subterranean termites to the odors of the entomopathogenic fungus Isaria fumosorosea K3.
• To determine if termite attraction to nestmates is influenced by the presence of fungal odors.

Main Methods:

• Y-tube olfactometry was used to assess termite behavioral choices in response to fungal odors and nestmate cues.
• Chemical analysis identified key volatile compounds (3-octanone and 1-octen-3-ol) associated with I. fumosorosea K3.
• Quantification of these compounds on fungal conidia was performed using direct extraction.

Main Results:

• Termites generally avoided fungal odors when presented alone.
• Nestmate odor became attractive only when fungal odors were present in both olfactometer arms.
• Specific fungal volatile compounds, 3-octanone and 1-octen-3-ol, were identified and quantified on the fungal conidia.

Conclusions:

• Termite responses to pathogenic fungal odors are context-dependent, influenced by social cues.
• The presence of nestmate odor can override general avoidance of fungal volatiles.
• This study highlights the intricate chemical communication underlying social immunity in termites.