OCCUPATION OF SPACE BY THE CARABID BEETLE ABAX-ATER

The occupation of space by Abax ater Villers (Coleoptera, Carabidae) w as studied in a near-climax beechwood in Belgium in May-June 1990 usin g capture-recapture in a grid of 180 pitfall traps. Population density fluctuated around an average of 2,062 individuals per hectare, a roug hly constant value for 13 years as indicated by comparison with previo us data. Locomotor activity was weakly correlated with daily temperatu re, and was higher in males than in females. The spatial distribution of activity was weakly contagious, and increasingly approached a rando m distribution at larger scales. The contagious distribution was not e xplained by a small-scale heterogeneity in either temperature or food quantity. The movements appeared to conform to a typical random walk o ver relatively short distances; the mean distance covered per day by m ales was 1.8 m. ''Home range'' was estimated at 660 m2 on average, but was slightly larger in males than in females. From this it was estima ted that an individual is liable to encounter and interact with an ave rage of 543 other individuals in its trivial movements, which suggests a considerable mixing in the population. Abax ater in the beechwood s tudied thus provides an example among insects of an equilibrium specie s in which spatial heterogeneity plays a minor role.