Bats good for pest control

Bats good for pest control

‘A single ‘rat bat’ will eat 1,000 mosquitoes an hour’

BY KIMONE THOMPSON Associate editor features

Wednesday, March 05, 2014

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Plagued by mosquitoes? You might want to consider getting a bat.

It might not be practical — unless like Mike Schwartz and Susan Koenig of Windsor Research Centre in the Cockpit Country, you live in a forest dotted by caves — but it certainly is true; scientists say bats are effective in controlling mosquito populations.

"A single 'rat bat' will eat 1,000 mosquitoes an hour, and half its body weight every night in insects," Schwartz last Friday told a Panos training workshop dedicated to fostering collaboration between journalists and civil society organisations.

The bats came up during Schwartz's presentation on plans for building projects in Trelawny which he said threaten to destroy some of the North Coast forest and jeopardise the animals that live and feed there.

"A hundred thousand 'rat bats' live here, but feed here," he said, pointing to a map showing the Windsor caves in the forest and the coastal area near Coral Springs.

"If you cut down that forest the 'rat bats' who travel from Windsor to feed in the Coral Spring Protected Area won't be able to make it because their forest corridor would have been cut," he said, explaining that the forest corridor, and the size of it, were crucial to sustaining both plant and animal life as some species only do well at particular depths inside the forest as opposed to the fringes.

The risk is high for birds as well, according to Schwartz, who is currently undertaking a project, in tandem with the National Environment and Planning Agency, to track the white crown bald-plate pigeon over a two-year period to establish habits and patterns.

"It you cut the forest up in disconnected patches they become unsustainable. They need migration between the patches so that both the animals and the plants can maintain the biological diversity of the original forest... If you cut down that mangrove area, it is not that that bird will just go somewhere else. They might, but there won't be enough food for those birds to live. In other words, they will die," the scientist said.

Back to bats, however, Koenig has been doing research on the creatures for the past few years, recording things like the frequency, length and power of different species' calls, the time of night that they are most active, which species use which type of habitat, etc. She and Schwartz agree that 'rat bats', as they are often called in Jamaican parlance, are generally misunderstood, given their traditional association with death, ghosts, and evil spirits, and maintain that they provide valuable services to humans, notably insect control, pollination and forest regeneration.

A document produced by Windsor Research Centre explained that there are three types of bats: Insectivorous, fruit-eating, and nectar-feeding.

"Insectivorous bats consume enormous quantities of nocturnal insects, including many that are harmful to crops and are pests to humans. For example, a bat the size of 14 grams would be capable of consuming over 1,000 insects per night, including mosquitoes. A colony of 50,000 of this species, as is the estimated population for Windsor Great Cave, would consume nearly 18 billion insects per year," it says.

"Fruit-eating bats are the most important seed-dispersing mammals in the tropics. Because they generally defecate in flight, seeds are dispersed away from the mother tree, thus increasing a seedling's chances of survival. In forest regeneration studies in Africa, Mexico, and Asia, bats were responsible for dispersing 75-95 per cent of all seeds, with birds, primates, and other animals accounting for the balance," according to the information from Windsor.

Meanwhile, nectar-feeding bats, along with some fruit bats that visit flowers, "pollinate thousands of bat-dependent tropical trees and shrubs...including banana, mango, guava, avocado, fig, and cashew".

Their contribution to humans can also be expressed in terms of their phosphate-rich excrement -- guano -- which may be added directly to plants as fertiliser.

The Centre for Ecology and Conservation Biology at Boston University backs up Schwartz and Koenig. According the centre's website, "bats should be protected as important members of natural communities because of their importance in controlling insects, dispersing seeds, and pollinating flowers".

Adds the Jamaica Caves Organisation on Facebook: "Seriously, these little mammals are responsible for a lot of the new fruit trees, including coffee, that you find growing wild around the island."

There are roughly 100,000 bats in all the Windsor caves.

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