REPRODUCTIVE BIOLOGY OF BORNEAN <em>NEPENTHES</em> (NEPENTHACEAE) SPECIES

Abstract

A study on the reproductive biology of Bornean Nepenthes species showed Nepenthes to exhibit reproductive syndromes that suggest insect pollination. A pollen trapping experiment in N.villosa showed that wind played no part in pollination. The presence of nectar licking insects and the absence of nectar-sucking insects such as butterflies is correlated with the morphological nature of sepal nectar glands. Diptera is the main visitor group in N. rajah, N. kinabaluensis and N. villosa; Hymenoptera and Diptera are the main visitors in N. curtisii ssp. zakriana and N. reinwardtiana. The absence of ants in N. villosa and N. kinabaluensis may be due to the high altitude habitat of the plants which is unsuitable for ants, or the presence of ant-repellent nectar. Insect activity around the inflorescence is influenced by local weather conditions and the stage of development of the inflorescence. Nepenthes flowers are clustered into long inflorescence and are positioned well above the surrounding vegetation or grow into the canopy of tall trees in disturbed forests. This conspicuous appearance not only attracts potential pollinators but also separates them from the pitcher traps thus reducing the competition between them.