Agriculture
Earth-Friendly Fabrics
Middle school science adventures
Got Milk? How?
Amphibians
Frogs and Toads
Newts
Salamanders and Newts
Animals
Hot Pepper, Hot Spider
Roach Love Songs
Sea Giants and Island Pygmies
Behavior
Supersonic Splash
Dino-bite!
From dipping to fishing
Birds
Woodpecker
Storks
Emus
Chemistry and Materials
Heaviest named element is official
A Butterfly's Electric Glow
Scientist Profile: Wally Gilbert
Computers
New twists for phantom limbs
Secrets of an Ancient Computer
Computers with Attitude
Dinosaurs and Fossils
Did Dinosaurs Do Handstands?
Mini T. rex
Digging for Ancient DNA
E Learning Jamaica
Results of GSAT are in schools this week
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Earth
Plastic-munching microbes
In Antarctica watch the heat (and your step)
Rocking the House
Environment
Will Climate Change Depose Monarchs?
What is groundwater
Pollution Detective
Finding the Past
The Taming of the Cat
Stone Tablet May Solve Maya Mystery
Decoding a Beverage Jar
Fish
Electric Catfish
Electric Ray
Flounder
Food and Nutrition
Chocolate Rules
A Pepper Part that Burns Fat
Healing Honey
GSAT English Rules
Subject and Verb Agreement
Adjectives and Adverbs
Who vs. That vs. Which
GSAT Exam Preparation Jamaica
Tarrant High overcoming the odds
2014 GSAT Results for Jamaican Kids
GSAT Exam Preparation
GSAT Exams Jamaica Scholarships
Results of GSAT are in schools this week
42,000 students will sit for the GSAT Exam in two weeks
GSAT Exam Preparation
GSAT Mathematics
How to Slice a Cake Fairly
GSAT Practice Papers | GSAT Mathematics | Maths
Math Naturals
Human Body
What the appendix is good for
Electricity's Spark of Life
Music in the Brain
Invertebrates
Daddy Long Legs
Flies
Centipedes
Mammals
Scottish Folds
Capybaras
Bats
Parents
How children learn
Choosing a Preschool: What to Consider
Raise a Lifelong Reader by Reading Aloud
Physics
One ring around them all
The Mirror Universe of Antimatter
The Particle Zoo
Plants
Springing forward
Plants Travel Wind Highways
Nature's Alphabet
Reptiles
Lizards
Crocodilians
Pythons
Space and Astronomy
A Dusty Birthplace
Killers from Outer Space
No Fat Stars
Technology and Engineering
Drawing Energy out of Wastewater
Bionic Bacteria
Machine Copy
The Parts of Speech
Pronouns
What is a Preposition?
Countable and Uncountable Nouns
Transportation
Are Propellers Fin-ished?
Flying the Hyper Skies
Reach for the Sky
Weather
Arctic Melt
Polar Ice Feels the Heat
The solar system's biggest junkyard
Add your Article

To Catch a Dragonfly

Try to catch a dragonfly. I dare you. "They're so quick and so smart, it sometimes takes us hours with five people to catch one," says Martin Wikelski. He's an ecologist at Princeton University in New Jersey. The pencil-thin, four-winged insects hover and dart, changing directions in an instant. "They're amazing," Wikelski says. "They're like little helicopters." Despite the challenges, scientists chase dragonflies to better understand their behavior, their habitats, and the dangers that threaten them. Surprises keep popping up, and dragonflies are giving researchers new ways to think about interactions in nature. Long-distance flyer Dragonflies date back at least 250 million years, says Daniel Soluk, an ecologist at the University of South Dakota in Vermillion. Alongside dinosaurs, they flitted across the prehistoric landscape on 2-foot-wide wingspans. Although dragonflies have been around for a long time and live in many parts of the world, scientists still know remarkably little about them. You've probably seen dragonflies. The insects are welcome picnic guests because they eat mosquitoes. What you might not know is that some of these mosquito hunters are long-distance flyers. Out of about 5,700 known species of dragonflies, as many as 50 species fly to warmer places for the winter, just like migrating birds do. Unlike birds, however, dragonflies appear to migrate in only one direction. Mom and dad may migrate south for the winter, but it's the next generation that probably makes the return trip. Radio alert To confirm that certain dragonflies migrate, Wikelski and his coworkers used eyelash adhesive to attach tiny radio transmitters to individual insects. Even though the devices were very small, they still weighed about one-third as much as an adult dragonfly. Luckily, dragonflies can carry heavy loads. "They seemed totally fine with it," Wikelski says. In their experiment, Wikelski and his team used an airplane to track 14 dragonflies carrying transmitters. Twelve days of observations confirmed that the dragonflies did migrate. When temperatures dropped two nights in a row, the researchers found, the dragonflies took off southward. In less than 2 weeks, some of the insects covered about 60 kilometers (37 miles). Some dragonflies go even farther, Soluk says. They've been known to show up on ships hundreds of miles out at sea. Mysterious flights Strangely, no one has ever observed dragonflies flying north in the springtime, even though it must happen. "Sometimes, dragonflies show up in New Jersey when ponds are still frozen," Wikelski says. The insects had to have come from somewhere else because dragonfly eggs need liquid water to hatch. "This is the kind of stuff that kids can observe," he notes. By making such observations, students can help researchers understand where dragonflies come from and where they go. Of the many remaining questions about dragonfly migration, Wikelski is particularly interested in finding out how much energy their journeys require. Evidence suggests that they simply ride the wind, so migration might be easy. He hopes someday to track dragonflies using satellites in space. Puzzling patterns Because of disappearing wetlands, the use of pesticides, and changes in groundwater flow, some dragonfly species are threatened with extinction. But scientists are discovering quirks in the behavior of these insects that might help keep them from dying out. When Soluk started studying an endangered species called the Hine's emerald dragonfly, for example, he was puzzled: Sometimes these dragonflies were easy to find, but at other times they were impossible to locate. For instance, when streams flowed in the spring, sampling turned up lots of Hine's emeralds. As the water dried up, the dragonflies disappeared. Then, next spring, their population boomed again. This species doesn't migrate, so they were obviously hiding somewhere. But where? "We spent a lot of time looking in places where we thought they might over-winter," Soluk says. After repeated failures, the researchers checked the last hiding spot available: crayfish burrows. Crayfish eat Hine's emeralds, so it seemed an unlikely place for them to be. "In the first burrow, we found two [dragonflies]," Soluk says. "In the second, we found 24. There were as many as 74 in one burrow." Saving endangered species These findings suggest that saving an endangered species can be complicated. It would be easy, for example, to assume that getting rid of predators would help dragonflies, Soluk says. But in fact, Hine's emeralds depend on crayfish burrows for their survival. It's still not clear why crayfish don't eat the dragonflies hiding in their burrows. It's possible, for example, that the insects use camouflage or chemical odors to make themselves unappetizing. Scientists are finding similar interactions among other creatures, including alligators and fish in Florida. "Ecosystems are very complicated networks of interaction," Soluk says. "We need to know all of the links before we start messing with them." The best way to protect dragonflies, Soluk says, is not to destroy their predators but to protect their habitats. With ever-expanding development and pollution, wetlands are disappearing, and dragonflies are losing sources of fresh groundwater. By saving wetlands, we can save more than the Hine's emerald. "They're an indicator for a whole lot of other species that are vanishing," Soluk says. So, if you manage to catch a dragonfly, be gentle. Take a close look. Then, let it go. It has important work to do.

To Catch a Dragonfly
To Catch a Dragonfly








Designed and Powered by HBJamaica.com™