Now is the time to enjoy the dragons of summer
By Gary Raham
Nature Writer and Illustrator
Modern cars may skim down the highway with sleek exteriors and aerodynamic
contours, but auto enthusiasts still appreciate classics like the rugged
Model-T that was able to survive rutted trails more suited to horses.
Likewise, entomologists--not to mention the average nature enthusiast
--love to observe the rainbow colors of butterflies and the seemingly infinite
variety of beetles, while still marveling at the classic insect remnants
of Paleozoic times called dragonflies. You can find them easily on local
foothills trails or even invite them to your own yard with a bit of planning
to accommodate their needs.
Dragonflies resemble biplanes with two pairs of large, transparent wings
extended, even when at rest. Their huge eyes may remind one of goggles
old aviators used flying in open cockpits.
Dragonflies have many common names including mosquito hawks, devil's darning
needles (or devil's horses) and snake doctors. While European common names
tend to associate dragonflies with evil, they are considered omens of good
luck in Japan and much of Asia, and commonly appeared as art motifs in
Native American southwest art.
Dragonflies are not only harmless to humans, but they consume lots of potentially
disease-carrying mosquitoes and are a wonder to observe as they dart and
dive in search of prey or a mate. With little economic importance, however,
they remain understudied and sometimes misunderstood.
If their flying needle form looks intimidating, consider what it would
be like to meet their Permian relatives that lived some 300 million years
ago. Meganeuropsis permiana, found in the Kansas Elmo Formation, stretched
28 inches from wingtip to wingtip. Some of our own small mammalian ancestors
would have done well to stay out of their way.
Dragonflies are professional predators as both larvae and adults. Adults
possess wrap-around eyes with some 280 degrees of acute vision. Their spiny
legs hang down like grappling hooks and surround their prey in a basket-like
cage. Independently movable wings give them a maneuverability that's the
envy of helicopter pilots.
But their larvae (nymphs) are the really awesome killers. They hatch from
eggs deposited by females in ponds, lakes, streams or any body of available
water. In fact, females will sometimes dive bomb the shiny hoods of cars,
mistaking them for puddles. Larvae look like six-legged tanks armed with
hook-like teeth that spring forward on a hinged extension of their mouth
parts and impale mosquito larvae, tadpoles, small fish and whatever else
blunders by. Once hooked, the prey gets hauled back to the dragonfly nymph's
real chewing apparatus, the mandibles, where they are cut to munchable-sized
shreds.
Dragonflies spend 98 percent of their lives as nymphs. The colorful adults
are merely sexual-phase show-offs, but watching them is fun. Males stake
out territories near ponds or other bodies of water. A male uses the tip
of his abdomen to transfer a sperm packet from his ninth abdominal segment
to his second so the claspers on his 10th segment will be free to grab
a passing female by the neck. Once so commandeered, the female loops her
abdomen around to snag the sperm packet with her sexual organs. These dragonfly
ring gymnastics can occur either while perched on a plant stem or in flight.
The male may stay attached until the female lays her eggs or just hang
around to make sure another male can't claim paternity.
In the mid 1990s, Texas researchers Forrest Mitchell and James Lasswell
needed a good way to record and identify dragonflies for a water-quality
project. They developed a technique using a portable scanner that produced
beautiful results by scanning live specimens that could then be returned
to the wild. They outline their techniques and show off their photography
in "A Dazzle of Dragonflies" (Texas A&M University Press, 2005). Their
web site (www.dragonflies.org) provides much additional information and
resources and allows dragonfly aficionados to exchange information.
Mitchell and Lasswell encourage people to attract dragonflies to their
yards by creative garden planning that includes elements of standing or
flowing water - water being essential to dragonfly reproduction. Even a
150-gallon water garden will attract a variety of dragonflies and damselflies.
Females will lay eggs that hatch into nymphs, which you can also observe
or raise in small containers to directly see which nymphs produce which
dragonfly adults. Adults like to perch on nearby plants and some nymphs
require soil at the bottom of the water container in which to burrow.
A Colorado State University entomologist, Boris Kondratieff, also maintains
a USGS web site on dragonflies and damselflies of the United States at
www.npwrc.usgs.gov/resource/distr/insects/dfly/dflyusa.htm. Click on Colorado
to find lists of species and some photos of species found in each of Colorado's
counties.
Naturalists don't need fantasy video games while the local dragons of summer
are flying outside. These insects provide hours of pleasurable observation
and a solid appreciation of classic insect design.
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