The inline image of a desert species of Calomyrmex possess large mandibular glands which contain a brightly coloured secretion.

This study investigates the role of the gland as part of the alarm/defence system of the species. The alarm promoting properties of the secretion are demonstrated. The defensive role of the secretion is studied from three aspects; the possible toxicity towards other insects; the repellent and/or repugnant properties towards another ant species; the responses of insectivorous vertebrates to Calomyrmexinline image and to other food items, some of which are treated by application of the secretion prior to presentation. The significance of the colour of the secretion is also discussed.