CANOPY KNOCKDOWN OF ARTHROPODS IN EXOTIC PLANTATIONS AND NATURAL FOREST IN SABAH, NORTHEAST BORNEO, USING INSECTICIDAL MIST-BLOWING

Canopy knockdown of arthropods using mist-blowing was carried out in B rumas, Sabah (north-east Borneo), in plantations of exotic (non-indige nous) tree species (Acacin mangium, Eucalyptus deglupta, Gmelina arbor ea, Paraserianthes [=Albizia] falcataria, and Pinus caribaea), plus se condary natural forest and dense understorey within E. deglupta stands . Each habitat had three 1 m(2) samples taken four times in one year. The average arthropod species richness within the stands of the exotic tree species ranged from 27 in E. deglupta, to 68 in natural, seconda ry forest. The total number of individuals caught ranged from 137 in G . arborea to 1628 in secondary forest. The dense and plant-species ric h understorey within E. deglupta stands yielded both higher numbers of species and individuals than the eucalypt trees themselves, indicatin g the importance of allowing the development of a luxuriant understore y for the enhancement of conservation and biodiversity. Though arthrop od biodiversity is reduced by the conversion of tropical forests to pl antations, abundance and richness are still substantial in the latter habitats.