Posted on 06/30/2007 5:11:14 AM PDT by Dysart
MASON -- Several hours before dusk, the Mexican free-tailed bats begin stirring inside the Eckert James River Cave outside of Mason.
As dusk approaches, the bats explode from the cave's mouth, creating a tornado-like vortex that allows the colony to soar higher and higher in the night sky.
During the last decade, scientists have learned these nightly feedings offer far greater benefits than providing entertainment for tourists.
Scientists gathered at the cave about 100 miles northwest of Austin are heralding them as nature's pesticide.
The research shows that some of the bats' favorite delicacies are insects like the corn earworm (also known as the cotton bollworm) and the tobacco bullworm, which are scourges to farmers.
"Only recently have we begun to understand the benefit they have been giving farmers and ranchers. They've been acting as nature's interceptors, preventing many of these pests from traveling farther into the Corn Belt in the upper Midwest and parts of the Northeast," said John Westbrook, a research meteorologist for the USDA Agricultural Research Service in College Station.
Billion-dollar bats
Because of that newly discovered benefit, scientists have dubbed them billion-dollar bats because research indicates pests cost U.S. farmers about $1 billion annually.
Now in the fourth year of a five-year research project in South Texas near Uvalde, the scientists are studying the benefits the bats provide farmers who raise corn, cotton and other crops.
The project, funded by a $2.4 million National Science Foundation grant, is a joint effort of Boston University, the University of Tennessee, the U.S. Department of Agriculture and the Texas Parks and Wildlife Department
The project has provided conclusive evidence that the bats follow the migratory patterns of the corn earworm, which can travel through to Texas' Cotton Belt and the Midwest's Corn Belt in its moth stage.
"The bats are able to track the ebb and flow of these insects," said Gary McCracken, an evolutionary biologist with the University of Tennessee. "The pests are very episodic, they flush and then disappear but the bats somehow follow these fluctuations. That shows they are effective control agents."
In a 2006 report in the scientific journal Frontiers in Ecology and the Environment, the research team said the bats provided a $1.7 million benefit to the eight South Texas counties in their study area.
The figure accounted for lower pesticide costs and a yield loss that was avoided by the bats' presence.
"I think the initial reaction of Midwest farmers to that figure may be, 'So what?'" Westbrook said. "But that's where we need to educate them that the bats reduce the number of pests that reach them. If the bats weren't down here in Texas, far greater numbers of these corn earworms would migrate northward into these states."
Tracking bats by radar
In the early 1990s, meteorologists in the Austin-San Antonio area were puzzled by false echoes resembling storms that showed up every summer night.
The local National Weather Service site had just started using Doppler radar and meteorologists quickly learned that the echoes were bats heading out on their nightly feeding runs.
Scientists pounced on the information to track the bats' feeding habits.
And as they studied them, they noticed that the bats were primarily gravitating toward farming areas instead of ranches across the Texas Hill Country.
McCracken and Westbrook eventually teamed up to track the movements of bats and moths.
They were eventually able to hear the sound of bats at the same elevation the moths were flying.
"That was our eureka moment, where we connected the dots and put the two together," Westbrook said.
Mosquito diet is a myth
But one benefit that bats don't provide is controlling mosquito populations, McCracken said.
The scientist studied bat droppings and learned that moths make up a significant part of their diet. Mosquitoes comprise very little of their daily diet.
"They're just too small," McCracken said. "I think the only place you may see mosquitoes make up a significant part of their diet would be in places like Alaska where the mosquitoes are huge."
Best place for bats
Over 100 million bats may soar across Texas skies every summer night in search of food. And they eat a lot of bugs: female bats may consume up to two-thirds of their body mass nightly while feeding their young.
But recent research by Boston University professor Thomas Kunz, the lead bat researcher for the National Science Foundation project, indicates the population numbers may be smaller than first thought.
Using infrared imaging, Kunz's team of scientists believe that the long-held estimates may be overstated.
"Whether the numbers were exaggerated or populations have actually declined we still don't know, but some of the caves may be significantly less than we first thought," Kunz said.
At the Eckert James River Cave, for example, Kunz said the actual population may be closer to 1.5 million rather than the 4 million bats normally cited.
But Kunz said that doesn't diminish the significance of the Texas population.
"This is the best place in the United States and one of the best places in the world to see bats," Kunz said. "The bats that come to Central Texas every year comprise one of the most important populations in the world."
Kunz, who has studied bats across the globe, said the Eckert James River Cave is one of the best places to watch bats up close and personal.
"Normally you are behind a barricade or some distance away," Kunz said. "Here the bats are right on top of you. If you're brave enough to sit on the front row by the lip of the cave, the bats will fly within inches of your face. That's why this is my favorite place in Texas to see bats."
Cute little bugger, isn’t he??
Ugly critters but fascinating as hell!
Yeah, I have some bat boxes on my property,but never have been able to entice them. Probably too urban for them.
As a kid we would serve tennis balls into the air at sunset and watch them dive bomb the balls.
Interesting how God in His infinite wisdom provided for this planet
Wow...bats eat bugs, what a revelation.
Mexican free-tailed bats doing the job American bats wont do.
Yepper, even the bats prefer to live and work here in Texas! Probably cause our farms are not irrigated with sewer water.
Proving yet again that nearly EVERY creature is on the earth for SOME purpose.
Scientists are, howeve, still studying Ted Kennedy...
Proving yet again that nearly EVERY creature is on the earth for SOME purpose.
Scientists are, however, still studying Ted Kennedy...
I dunno...
I took a vacation to Utah 2 years ago. NO mosquitos, lots of bats. Here in Connecticut we have lots of mosquitos, few bats. Maybe he means the Texas bats don't eat mosquitos.
We would throw those little balsa airplanes up, and sometimes they would take a bite out of the wings.
I had about a half-dozen of them unroll out of my rollup-garage door one morning.
Scared the little bastards to death and they don’t wake up very fast. Half of them weren’t able to avoid the floor! Ouch! But they all eventually licked their concussions and flew off.
Took me several seconds to figure out what they were....thought pieces were falling out of the door spring mechanism!
Kinda like a boot camp bed dump I guess.
I wonder if the dirt-dauber wasps would take over a “bat house” here, though.
I've thought of putting one up. The guy at the local birdhouse store says the bats here are very particular and bathouses need to be at least 20 feet off the ground.
I’ve always thought bats were cool.
In the old neighborhoods of the Denver area, with established trees and ponds, I would see them all the time skimming the treetops as sunset. I don't think its an urban problem.
quick...
put up some green energy, say a wind farm, to stop illegal alien bats...
I think a more likely reason for the disparity in mosquito populations is that Utah is a lot dryer than Connecticut. Insects thrive in wetness, laying their eggs in stagnant standing water, and are at their worst when humidity is higher.
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