Site map | NSS Home Page
Official Magazine of the Nature Society (Singapore)
  No Bats, No Durians
Part 1 | Part 2

The fruit bat is an important pollinator and seed dispenser and traditional farmers in Malaysia know that one of the species, the Dawn bat, is a very effective pollinator of durian flowers which is why they say, 'No Bats, No Durians'. Yet this harmless creature has been hunted for its flesh, for sport and even as a crop pest! Lim Gaik Kee from Sahabat Alam Malaysia (SAM) wrote this article for Malaysia's Utusan Konsumer to wake us up to what wantonly destroying this small mammal could mean to our forests and fruit orchards. (Naturewatch has adapted this article for its readers and credits the author and Utusan Konsumer for their research and their views.) Photographs by Lee King Li (unless otherwise stated).

Durians are a highly priced and relished fruit and yet few people give any thought as to how the durian flower develops into thorny fruits that conceal the most delectable creamy pulp-covered seeds. Yes, for the durian and other jungle and orchard fruits and even beans (like petai) to be pollinated, the fruit bat is indispensable. In fact all bats are friends of nature and of man yet this flying mammal is a much misunderstood, unappreciated and even feared creature. Most of us know of bats only as rat-like creatures with wings and our encounters with these animals are most likely to occur only when we explore caves and come across them either swarming out of the cave or massed inside the cave where they can be seen hanging upside down and producing tons of excrement, 'guano' which is distinctively smelly.

But bats are in fact fascinating nocturnal creatures with warm bodies and soft fur. They usually shun daylight and if seen at all outside of caves it is normally only at twilight where their forms appear as silhouettes zigzagging across the darkening sky. To appreciate these much maligned little creatures, we have to look at the many positive roles they play.

Firstly, bats of the Megachiroptera group, i.e., the fruit-eating species, are, along with birds and monkeys, among the most important seed-dispersing animals in tropical rainforests. These fruit bats, together with nectar-eating bats, are also the creatures responsible for the pollination of tropical and subtropical trees and shrubs. And where the durian tree is concerned, it is the Dawn bat or Cave Nectar Bat (Eonycteris spelaea) that is the only effective pollinator of its flower. (These are the findings of Dr Marty Fujita from Boston University).

The durian's large creamy flowers are clustered on the underside of its sturdy branches and very accessible to bats. Dawn bats are drawn to the copious amounts of fragrant nectar exuded by the Durian's night blooming flowers. No wonder there is a popular local saying, 'No bats, no durians'. Every year, durian lovers, can look forward to some bountiful crops on our island of Pulau Ubin as Durian Bats have been found there.

Another crop that relies on fruit bats for pollination, again according to Dr Fujita, is the petai, a popular bean (Parkia speciosa and P. javanica) sold in Malaysian markets and served as a vegetable in restaurants. This bean comes from a large leguminous tree whose blooms are light-bulb shaped and suspended from pendulous stalks. Like the durian flower, the petai flower is easily accessed by the fruit bat.

Another very valuable tree whose propagation depends on bats is the Sonneratia. The Sonneratia is a very important tree because it protects the whole ecosystem of the mangrove against tidal and wave action. Moreover, wood from these trees was traditionally and are still harvested to be used as poles, furniture, footwear (sandals) and also to be converted to charcoal. The bats that are responsible for pollination are the Dawn Bat, the Long-tongued Nectar Bat (Macroglossus minimus) and the Short-nosed Fruit Bat (Cynopterus brachyotis).

But these are not the largest of the bats found in mangrove forests. In fact, two of the largest bats in the world roost in mangroves and they are the Large Flying Fox (Pteropus vampyrus) and the Island Flying Fox (Pteropus hypomelanus). The first bat was named after vampires apparently because of its sinister appearance and nocturnal habit, even though it is a frugivore. These large fruit bats have a pointy snout making them resemble foxes which is why they are commonly called flying foxes. In Sarawak the most prominent bat is the Cave Nectar Bat.

Besides their role as fruit pollinators, the other family, the insect-eating bats of the Microchiroptera group are the most important controllers of insects that prey on crops. Insect-eating bats aid in the biological control of insect swarms that would otherwise devastate crops along Sarawak's Baram and Tutoh rivers wrote Rambli Ahmad in the New Straits Times (Oct 12, 1996). These Microchiroptera bats use echolocation or sonar techniques for navigation as they hunt.

Short-nosed Fruit Bat
Cynopterus brachyotis

At night, this bat may be seen
visiting flowering or fruiting
wayside trees even right in
the heart of town

Singapore durian-lovers prize the
more delectable local varieties
like these growing on old trees
on the island of Pulau Ubin

Only several out of the whole
bunch of durian flowers will be
successfully pollinated to
develop into fruit

Glossy Horseshoe Bat
Rhinolophus rufulgens

This is one of our smallest species.
An insectivore, it is important part
of the forest ecosystem as it keeps
insect populations in check

Dusky Fruit Bat
Penthetor lucasi

This bat was mist-netted for
studies and eventually released.
Researchers have found that this
species is an effective disperser
of seeds. Even its roosting areas
can be recognised by sprouting
seeds. Fortunately for us, small
colonies of this bat are still
found in Singapore forests.

Trefoil Horseshoe Bat
Rhinolophus trifoliatus

The intricate noseleaf structure
helps these bats to echolocate
and find their insect food

Cave Nectar Bat
Eonycteris spelaea

This bat is being examined and
measured. Local bat researchers
are trying to find out more about
these beneficial creatures before
they go extinct in Singapore.

Flying foxes
Pteropus sp.

These bats roost in the open.
Many of these giant fruit bat species
are endangered world-wide, from
being hunted to loss of their habitats.
Rare in Singapore, those sighted
are most probably visitors from neighbouring countries
Photo by AT

Another example of insect eating bats that Rambli cited is the Philippines Horseshoe Bat (Rhinolophus philippinensis). It appears that this bat is even a choosy eater as it seems to feed only on the most succulent and nutritious parts of the insect, namely its stomach. Rambli deduced this when he came across a swarm of dead termites with all their abdomens missing during one of his trips to the Mulu Caves area in Sarawak. The bats had good reason to feast lightly too. They cannot fly well on a full stomach. (Perhaps gluttonous humans should take a cue from the bat).

Because bats have up till now been among the least researched and therefore least appreciated of mammals, we have not merely destroyed their habitats by urbanisation and development but have actually hunted them as pests to be exterminated! Perhaps our ignorance will haunt us as 'their death as a species merely precedes our own..

<<Back to Issue contents

© Nature Society Singapore