Studies of foraging galleries and the invasion of living tres bu Coptotermes acinaciformis and C. brunneus (Isoptera)

Abstract

The establishment of colonies of Coptotermes acinaciformis (Froggatt) in living trees results in a central "pipe" being eaten out, this being filled with "mudgut" material. Adjacent trees sometimes contain a clear pipe in the trunk and the connection between these trees and the central colony tree was investigated. The gallery systems radiating from colonies in trees in coastal forests of eastern Australia were studied. In the first study subterranean galleries from one colony were traced to nine other living trees; in the second study, in a different tree association, 15 living trees were attacked from the central colony. Galleries from a colony persisting in a high stump were traced to three living trees in a further study. In each colony studied, dead trees, logs, and stumps were also attacked. The galleries from each colony extended over an area of 0.4 acre, the maximum length of any gallery being 156 ft. In some areas of Australia C. acinaciformis can persist in mound colonies after the host trees have been eaten out, and foraging galleries from a mound colony in Western Australia were traced to several gimlet gums (Eucalyptus salubris F. Muell.). In the Murchison River basin of Western Australia, mound colonies of Coptotermes brunneus Gay occur in an area of sclerophyll woodland and mallee. The foraging galleries were traced to two species of Eucalyptus, one of which was much more susceptible than the other. The sand adjacent to the galleries of C. brunneus is impregnated with some cementing substance. Evidence on the maximum foraging distance of 150 ft for C. brunneus is given. In both species the invasion of trees was often through the living bark tissue covering a root or at the base of the tree trunk. This is in contrast to the initial entry of colony-founding pairs, which can only enter through a tree injury.