Cyclopentyl ketones: identification and function in Azteca ants.

The anal gland secretions of dolichoderine ants in the genus Azteca are fortified with cyclopentyl ketones. Since these compounds, 2-methylcyclopentanone, cis-1-acetyl-2-methylcyclopentane, and 2-acetyl-3-methylcyclopentene, release sustained alarm behavior in ant workers, they constitute a new chemical class of insect pheromones. The ketones probably also function as defensive compounds and thus are part of the ants' alarm-defense system.