This is the commonest species of this widespread genus to be found in Britain; some other tramp species may occur sporadically. The workers are small (2.5-4 mm) and dark brown or black with a robust morphology typical of myrmecine ants. All castes have a two-segmented 'waist' and pectinate spurs on all tibiae, along with propodeal spines and a sting in the females. Despite its size, T. caespitum is an aggressive ant and uses its sting freely; it is often the dominant ant species where abundant. There is a marked dimorphism between the castes with males and gynes being much larger… Read more

Identification keys and general biology are given in Richards (1980), Gauld and Bolton (1988) and Yeo & Corbet (1995).

Previously known as H. integrum (Dahlbom, 1854). Identification keys and general biology are given in Morgan (1984), Gauld and Bolton (1988), Kunz (1994) and Linsenmaier (1997).