Merlin Tuttle Bat Flash

Australian Flying Foxes Need Help

By Merlin Tuttle

As one who in 1985 played a lead role in convincing the New South Wales (NSW) Minister for the Environment and Planning, Bob Carr, to provide statewide protection for flying foxes, I am extremely disappointed to see  such progress reversed decades later by a predecessor. Grey-headed flying foxes are essential pollinators and seed dispersers upon which many of Australia’s unique plants and animals rely.

Nevertheless, their numbers have declined dramatically over the past hundred years. They first were massively exterminated by fruit growers, because during periodic droughts, when forests failed to flower, starving bats would invade orchards. Thanks to excellent research, orchards can now be protected. However, the bats’ traditional roosting habitats often have been overrun by urbanization. Once again these bats are in trouble, often with few options remaining. In small numbers, they may be enjoyed. But during unpredictable spikes in gum tree flowering, these sophisticated commuters can be attracted long distances. When bats weighing up to two pounds and having wingspans of more than three feet suddenly increase by as much as 10-fold, noise and odor can become a serious problem.

Gray-headed and other flying foxes are essential pollinators and seed dispersers for Australian forests. However, they are killed in massive numbers during occasional droughts when native trees fail to flower, forcing them to resort ot orchard fruit which could be protected with netting.
Gray-headed and other flying foxes are essential pollinators and seed dispersers for Australian forests. This grey-headed flying fox (Pteropus poliocephalus) pollinating a rose gum tree (Angophora costata). Flying foxes are the continent’s most important long-distance pollinators and seed dispersers. However, they are killed in massive numbers during occasional droughts when native trees fail to flower, forcing them to resort to orchard fruit which could be protected with netting.

Excellent means of protecting fruit orchards have been developed, but urban nuisances have not yet been studied sufficiently to find viable solutions. As flying fox experts, Justin Welbergen and Peggy Eby recently explained in their insightful article, Not in my backyard? How to live alongside flying foxes in urban Australiagrey-headed flying foxes can travel thousands of kilometers in a single year and quickly respond to changing conditions far beyond the boundaries of any one state. To resolve nuisances without loss of essential services, we must learn much more about what attracts them to specific roosts and how best to provide suitable alternatives when their choices create nuisances. (more…)

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Bats and Chewing Gum

Halloween candy aside, it would be a stretch for most people to think of bats when they reach for a packet of chewing gum at the grocery store. But bats actually play a vital role in the ecology of the tree that helped give birth to the entire chewing gum industry.

The sapodilla (Manilkara zapota) is a tree that is native to the Yucatan and several other neighboring states in southern Mexico, as well as northern Belize and Guatemala, and became highly sought after in the 1800s for its white sap known as chicle that was used as a chewing gum. Sapodillas were brought into the U.S. sometime in the 1860s and several companies such as The Wrigley Company and Fleer began harvesting chicle from the trees – a series of diagonal cuts along the tree’s bark being the preferred method – to mass produce chewing gum. Now you know where the classic chewing gum Chiclets got its name from.

A Jamaican fruit-eating bat (Artibeus jamaicensis) feeding on Sapodilla fruit (Manikara zapota) in Jamaica. This fruit is native to southern Mexico, Central America, and the Caribbean. Bats are its primary seed dispersers. It is also a favorite fruit for human consumption, and its sap, forms a gummy latex known as “chile,” which gave rise to Chiclets chewing gum, and the founding of the chewing gum industry. In Jamaica, this fruit is known as the naseberry. Its seeds and leaves are used locally as medicinals, and it has beeen introduced in tropical areas worldwide.

So where do the bats fit in? Bats like the yellow epauletted bat and the Seba’s short-tailed bat were key in helping sapodilla trees flourish naturally in the first place because of their role as pollinators of the sapodilla flower.

Other animals and insects have a small place in the matrix of pollinating the sapodilla flower but bats are critical because the fur on their heads and necks becomes dusted with pollen, which they transfer to the stigma of the next flower they visit. They also carry off the trees’ sweet, pear-flavored fruit, eventually dropping seeds that may grow into new trees.

Worth noting is that both the sapodilla trees and their bat pollinators are mutually dependent. Because bats expend a tremendous amount of energy while foraging each night they need to feed on sources that are either abundant or very dense in caloric energy.

Sapodilla flowers produce a quantity and variety of nectar that meets the nutritional needs of the bat species that feed from them, and the flowers – white or cream colored with a rich, musky scent – are arranged in clumps below the foliage that allow bats to navigate between them in the dark.

Another plus: since bats can cover up to 38 kilometers a day they have the ability to carry pollen over a far larger area than insect pollinators, which helps to increase the genetic diversity among the sapodilla species.

So even though chewing gum production has long since moved away from relying on the sap of the sapodilla tree, know that hungry bats helped give birth to the industry in the first place.

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