0023-6152

AA00697606

23779

Unrefereed

0023-6152

AA00697606

Formica yessensis is a highly polyphagous predator with a broad spectrum of prey range, i.e., live and dead lepidopterous larvae, coleopterous adults and larvae, hemipterous adults as well as honeydew secreted by aphids. The results of experiments for examining the effect of predation by the ant with the physical check method revealed that the ant is extremely effective in controlling the younger larvae of the pine caterpillar moth, Dendrolimus specfabilis. The ant hunts in one of two ways. The first is a direct attack by worker ants on a twig. The second is hunting by numerous workers on the ground, where caterpillars have dropped to escape from the attack by ants on the twigs. In Korea this ant maintains a very high population density with supercolonies including a number of colonial nests in red pine forests. The predaceous activities of the ant are not density-dependent. When the pine caterpillar is scarce, the ant can maintain its population by feeding on the honeydew of aphids which are not a serious pest of red pine trees. The period of activity of the ant is as long as 200 days per year. These are outstanding characters possessed by the ant, which makes it as an effective biological control agent against the pine caterpillar moth. In addition to its role as an effective predator, the ant may also play an important role in soil improvement and plant enrichment. Therefore, the preservation of this ant species in natural habitats, and the transplantation of its colonies to non-inhabited forests should be recommended.