Calomyrmex

Species of Calomyrmex forage individually on low vegetation where they tend Hemiptera to collect honeydew as well as visit flowers and extrafloral nectaries to collect nectar and plant secretions. They only occasionally return to their nests with dead insects or other prey, and apparently do not attack living arthropods. During warm periods they may limit foraging to the cool morning and afternoon and during cooler weather they may only forage during warmer times of the day. Nests are in soil with a single small entrance which is sometimes surrounded by a low mound of bare ground.

When disturbed, these ants secrete white to bright orange fluid from the base of the mandibles. The colour of the secretions changes with the age of the worker, varying from white in young workers to dark orange in the oldest workers. These secretions have several roles. They act as an alarm signal to other ants in the area, as a defensive compound because of its viscous nature when exposed to air, and as a repellent to enemies or predators because of its repugnant properties. Its repellent properties are so strong that even small mammals will avoid these ants.



Worker of C. cyanaea from Queensland.

Identification
The antennal sockets are separated from the rear margin of the clypeus by a gap about as wide as the maximum scape diameter. The pronotum is separated from the metanotum by a distinct, flexible joint (visible as a distinct line separating these plates when viewed from above). The upper plate of the first segment of the gaster (first gastral tergite) is less than one-half the total length of the gaster.

Species of Calomyrmex are usually darkly coloured and often have strong iridescent green, blue or purple reflections. Most species are also covered with long, erect hairs. They are most similar to species of Camponotus in overall shape and size, but can be separated from them by the presence of a small opening above the hind leg (the metapleural gland opening) and in having all workers approximately the same size (being monomorphic) rather than varying in size ( being polymorphic). Although not diagnostic, most species of Calomyrmex can be recognised in the field by the distinct way they raise their pointed gasters as they run and by the distinct orange secretions which appear at the bases of the mandibles when they are disturbed.

Distribution and Habitats
Australian distribution

Regional Species Lists

 * Australia

Keys to Species

 * Australia