A preliminary survey of insect galls on dipterocarps in a lowland rainforest at Pasoh, Peninsular Malaysia

抄録

A preliminary survey of abundance and species richness of galling insects on dipterocarps was conducted in the forest canopy and forest floor of the Pasoh Forest Reserve in Peninsular Malaysia. At least 120 individuals and 13 sorts of galls were collected from canopy crowns of 15 of 26 dipterocarp trees (10 species) surveyed. In contrast, only one individual coccoid gall was found on the forest floor, despite careful searches of about a hundred seedlings, saplings, and young trees. This result shows that galls on dipterocarps are concentrated in the forest canopy, where young shoots suitable for gall induction and development are abundant. Although insect inhabitants obtained from the galls were not numerous, most of the galls were supposed to have been induced by dipteran or hymenopteran insects, and the rest proved to have been caused by beesoniid coccoids (Homoptera). This study suggests that dipterocarps harbor diverse galling insect species, of which the main domain is in the forest canopy.