In honeybee communication, which chemical is a major alarm pheromone released by worker bees?

In honeybee communication, isopentyl acetate is a major alarm pheromone released by worker bees.

Isopentyl acetate, also called isoamyl acetate, is associated with the alarm signal of worker honeybees. It has a strong odor often compared with bananas, and its release can alert nearby bees and increase defensive behavior. A worker may release alarm pheromone when it stings, because the sting apparatus helps disperse chemical signals near a perceived threat.

The compound is not the only chemical involved in honeybee defense. Honeybees use blends of pheromones, and the response depends on concentration, location, colony condition, and the type of disturbance. Isopentyl acetate is nevertheless the classic example used in explanations of honeybee alarm communication.

This signal should not be confused with the pheromones involved in the waggle dance. The waggle dance communicates the direction and distance of food using movement and sound, whereas alarm pheromones recruit defensive attention. Nor is the banana-like odor itself a universal command: bees integrate chemical information with visual and physical cues from nestmates and their surroundings.