Page 19 - BOOK OF PROGRAM ICAGRI 2

Abstract Keynote-3

PLANT-INSECT INTERACTIONS
Stephen G. Compton
University of Leeds · School of Biology

Abstract
The conversion of forests to oil palm plantations is one of the main drivers of
biodiversity loss in SE Asia. Established oil palm plantations are often
managed as near-monocultures that support very little animal life, but more
environmentally-friendly management offers a chance for a wider diversity of
animal life to be maintained. Fig trees (Ficus spp., Moraceae) support more
species of fruit-eating birds than any other tropical plants, and some fig trees
routinely colonise the trunks of oil palms. These are generally removed during
plantation management, but some species have the potential to support
beneficial insect and bird populations without reducing palm oil yields.

We recorded the presence of fig trees in oil palm plantations in West Malaysia
and examined their ecology. They comprised mainly the younger stages of
hemi-epiphytic species (strangler figs) and also creepers and true-epiphytes.
The strangler figs generally need to become large before fruiting, so they will
not often provide resources for fruit-eating vertebrates and once mature, their
large size might also have an impact on yields. In contrast, the true ephiphytes
of the Ficus deltoidea complex remain small, produce abundant fruits and
enhance the biodiversity of the plantations. In some plantations they can
reach high densities, but are absent from plantations where management is
intensive.

Ficus deltoidea are dioecious plants, with separate male and female
individuals. Like other fig trees they have tiny host-specific fig wasps as
pollinators. We found that the fruit production is pollinator limited and that
this may reflect unusually restricted flight distances by the pollinators – they
are reluctant to leave the male plants where they developed. environmentally-
friendly management of oil palm plantations needs to be more selective in
terms of removing epiphytes from palms, with plants such as F. deltoidea
encouraged, not removed.

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Agriculture Faculty, Universitas Syiah Kuala. All Rights Reserved