Alkylpyrazines in ponerine ants: Their presence in three genera, and caste specific behavioural responses to them in Odontomachus troglodytes

Abstract Alkylpyrazines were found in the mandibular gland secretions of three Ethiopian ponerine ants. The major components in Odontomachus troglodytes were 2,6-dimethyl-3- n -butyl- and n -pentylpyrazine; in Anochetus sedilloti 2,6-dimethyl-3- sec -butyl- and 2,5-dimethyl-3- n -pentylpyrazine, and in Brachyponera sennaarensis 2,6-dimethyl-3- n -butyl and n -pentylpyrazines. The male caste in O. troglodytes contained 2,6-dimethyl-3- n -hexyl- and n -butylpyrazine. In O. troglodytes caste-specific behavioural differences were found between males and workers in response to gland equivalent quantities of their pheromones. The fragile males retreated from the alkylpyrazines whereas the workers were attracted to and attacked the pheromone source. Large quantities (5 gland equivalents) of pheromones were also repellent to the workers.