Publication update 21: Project Pteropus press release: Durian Industry May Suffer Without Endangered Fruit Bats

Flying foxes pollinate regionally important fruit crop

Kuala Lumpur, 19 September – Scientists here have discovered that Southeast Asia’s highly popular durian tree is pollinated by locally endangered fruit bats known as flying foxes.

By putting camera traps in durian trees on Tioman Island, Malaysia, researchers collected video evidence showing the island flying fox (Pteropus hypomelanus) pollinating durian flowers, leading to the production of healthy durian fruit. The study has just been published in the journal Ecology and Evolution.

Fig.3
Still shots from a video recording of a flying fox feeding on durian flower nectar.

The spiky tropical durian fruit is highly prized throughout its native region. A ubiquitous icon of Southeast Asian culture, it is also a lucrative industry, generating millions of US dollars in local and international trade. And these economic profits owe a huge debt to bats.

Commonly referred to as flying foxes, large fruit bats of the genus Pteropus are severely threatened by hunting and deforestation. They are often sold and eaten as exotic meat due to an unsubstantiated belief that consuming them can help cure asthma and other respiratory problems.

On top of this, they are also persecuted and killed as agricultural pests, as some people claim that the bats cause damage and economic loss by feeding on cultivated fruits. Consequently, these factors have led to severe declines in flying fox populations worldwide.

Yet these bats actually play very important roles as seed dispersers and pollinators in rainforests, especially on islands. The disappearance of flying foxes could thus have disastrous repercussions for tropical ecosystems. Now, this international team of researchers from Malaysia, France, India, and Thailand, in collaboration with Tree Climbers Malaysia, has found that Southeast Asia’s durian supply could be affected too.

Fizi closeup
Professional tree-climber Fizie, from Tree Climbers Malaysia who collaborated with Rimba to put up camera traps in durian trees.

Dr. Sheema Abdul Aziz, who led the study in Malaysia as part of her PhD under the Muséum National d’Histoire Naturelle (France), said: “These are very important findings because they shed more light on the crucial ecosystem services provided by flying foxes. Previously it was known that the smaller, nectar-feeding bats are pollinators for durian – but many people believed that flying foxes were too large and destructive to play such a role. Our study shows the exact opposite: that these giant fruit bats are actually very effective in pollinating durian trees.”

According to Dr. Sheema, who is currently President of the Malaysian NGO Rimba, and a Visiting Academic at the University of Southampton, cave nectar bats are already being affected by limestone quarrying. How much has durian production already suffered due to declines in bat populations?

This is something Rimba plans to investigate further to initiate conservation action. “The island flying fox is already classified as ‘Endangered’ on Malaysia’s National Red List,” Dr. Sheema explained. “We want to reverse this downward trend. If people end up hunting flying foxes to extinction, it’s not hard to see that there could be serious implications for Southeast Asia’s beloved King of Fruits.”

durian fruits
Healthy durian fruit – the result of successful flying fox pollination on Tioman Island!

Access the article here:

Aziz SA, Clements GR, McConkey KR, Sritongchuay T, Saifful P, Muhammad Nur Hafizi AY, Campos-Arceiz A, Forget P-M, and Bumrungsri S. 2017. Pollination by the locally endangered island flying fox (Pteropus hypomelanus) enhances fruit production of the economically important durian (Durio zibethinus). Ecology and Evolution: doi: 10.1002/ece3.3213.

For further information, or to obtain versions of the press release in Bahasa Malaysia or French, please contact Sheema.

Update 6 October 2017:

Our press release has been picked up by local and international media! Check out the extensive coverage below:

The Star:

Dwindling flying fox numbers a thorny issue (video story)

Dwindling flying fox numbers, dying durian market

Flying foxes to be upgraded to ‘totally protected’ species

We need more flying fox researchers

Mongabay:

Bats key pollinators for durian production, camera traps confirm

National Geographic:

World’s smelliest fruit might not exist without this giant bat

Podcast of Sheema’s radio interview with Business FM station:

The role of flying foxes in durian pollination ecology

Update 10 October 2017: Our study just got a brief mention in a Nature News article about another recently published study that sequenced the entire durian genome:

How the durian got its sulfuric stench

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