Tetramorium caldarium (Roger, 1857)

(Figure 20 (a–c))

Tetrogmus caldarius Roger, 1857: 12 (w. q.) Poland. Palaearctic.

Diagnosis

Worker. Anterior clypeal margin entire; frontal carinae well-developed, reaching back to posterior level of eyes and more feeble behind eyes than in front; antennal scrobes less-developed or indistinct; eyes with seven or eight ommatidia in the longest row; propodeal spines small, triangular and acute; cephalic dorsum feebly and finely longitudinally rugulose. Body pilosity short, stout and blunt. Colour yellow or yellowish brown, gaster brown or blackish brown.

Geographic range

A successful invasive species with an African origin (Bolton 1980), widely distributed worldwide by human commerce (Wetterer and Hita Garcia 2015). In the Arabian Peninsula, this species has more successfully dispersed into undisturbed areas than Tetramorium simillimum, but is also known to become established in greenhouses. Wetterer and Hita Garcia (2015) have indicated that colonies of Tetramorium caldarium are successful in establishing colonies in greenhouses and heated buildings in temperate regions.

Ecological and biological notes

In India, this species is commonly found in disturbed regions with increased anthropogenic activities (Bharti and Kumar 2012), whereas in tropical and subtropical regions, populations are associated with greenhouses, zoos and heated buildings (Bolton 1980).