Bees eavesdrop upon informative and persistent signal compounds in alarm pheromones

Area of Science:

• Behavioral Ecology
• Chemical Ecology
• Animal Communication

Background:

• Pollinators are vital for ecosystems, but their foraging can be disrupted by predation risks.
• Bees utilize olfactory cues for communication, including alarm signals.

Purpose of the Study:

• To investigate olfactory eavesdropping on heterospecific (different species) alarm pheromones in bees.
• To determine if bees avoid alarm pheromones from other species at shared food resources.
• To identify specific alarm pheromone compounds and their characteristics influencing avoidance behavior.

Main Methods:

• Observational studies of bee foraging behavior at food sources.
• Chemical analysis of alarm pheromone compounds in different bee species.
• Electroantennogram (EAG) recordings to assess olfactory sensitivity in bees.

Main Results:

• Apis cerana foragers demonstrated avoidance of alarm pheromones from Apis dorsata and Apis mellifera.
• Avoidance was observed for isopentyl acetate (IPA), a common and volatile alarm pheromone.
• Apis cerana also avoided gamma-octanoic lactone (GOL), a less volatile compound specific to A. dorsata, showing heightened sensitivity to it.

Conclusions:

• Bees exhibit olfactory eavesdropping, avoiding heterospecific alarm pheromones at food sources.
• The strategy of eavesdropping is shaped by signal conspicuousness (abundance, commonality) and persistence (volatility).
• Species-specific sensitivities, like to GOL, play a crucial role in mediating avoidance responses.