Alkylpyrazine alarm pheromones in ponerine ants.

The mandibular gland secretions of the ponerine ants Odontomachus hastatus, O. clarus, and O. brunneus contain alkylpyrazines. These compounds, 2,5-dimethyl-3-isopentylpyrazine in O. hastatus and O. clarus, and 2,6-dimethyl-3-pentyl-, -butyl-, -propyl-, and -ethyl-pyrazines in O. brunneus, have previously not been found as animal natural products. These compounds function as powerful releasers of alarm behavior for Odontomachus workers and are probably also utilized as defensive compounds.