A PRELIMINARY STUDY OF ARTHROPOD DIVERSITY IN THE CANOPY OF Campnosperma zeyanica Thw, AT PEAK WILDERNESS SANCTUARY

Abstract

In recent times, canopy studies have revealed a wealth of information about thearthropod diversity that can be seen in the forest canopy. For instance, Stork(1997) sampled 19 trees of Luehea seemannii, a tree found in semi-evergreenforests of Brasil, which yielded 955 species of beetles. Another canopy studydone in venezuela yielded 972 species of beetles from six rain forest trees (Davieset al., 1997). However, in Sri Lanka, no studies have been done so far regardingthe canopy arthropods.

This study was done as a pilot project to assess the canopy arthropod diversity inSri Lanka. The study was conducted in the Peak Wilderness Sanctuary fromMarch to May 1999. A single tree of the common canopy species Campnospermazeylanica (Anacardiaceae), was selected and the knockdown pesticide Cyfluthrin,was applied to the canopy using 'Swin Fod SN50' fogger. Arthropods falling fromthe tree were collected on to plastic sheets suspended 1m above the ground leveland preserved in 70% alcohol. Arthropods were assigned to taxonomic orders andapproximate morphospecies.

A total of 228 individuals belonging to 18 orders were collected. Theseindividuals were separated into 111 morphospecies. Of the morphospeciesrecorded, the highest number belongs to order Diptera (33) followed by orderHymenoptera (22), order Araneida (14), and order Coleoptera (12). Rest of theorders were represented by 5 or less morphospecies. These results are based on asingle sample collected in March 1999. Yet a large number of species wererecorded indicating that the canopy arthropod diversity in Sri Lanka is likely to bevery high. Therefore, further investigations should be carried out to assess theactual diversity that exist in the forest canopy of Sri Lanka.