Who hasn't spent a few lazy moments sitting by a pond or stream watching those lovely, gauzy-winged insects called "dragonflies" and "damselflies"? And we have all wondered if these beautiful creatures had descriptive common names or only multi-syllabled scientific ones.
The difficulty arose from the fact that the last comprehensive monograph on these insects dated back to the 1950's, and no one had seen the need to create a list of common names that would be accepted by academic students of dragonflies and damselflies. Thus the many naturalists curious about the dragonflies and damselflies they saw on their adventures were at a loss for names until the last decade.
The common names now becoming established are as colorful as the insects themselves. Damselflies have names like spotted spread wing, Kiowa dancer, Aztec dancer, smoky ruby spot, double striped bluet, and desert firetail. Dragonflies have names like orange tipped clubtail, spotwinged basket tail, sand dragon, band-winged dragonlet, globetrotter, red-mantled glider, and blue dasher. All these species may be found in the Chihuahuan Desert and the Llano Estacado.
One of the best places to observe the Odonata (the order of dragonflies and damselflies) is Bitterlakes National Wildlife Refuge near Roswell, New Mexico. Over 90 species have been observed there, and for a number of years the town has held a Dragonfly Festival -- a much more down to earth celebration than their famed UFO celebrations!
Dragonflies don't spend much time at water. Instead, they roam over acres and acres, hunting flying insects. They come to water for displaying, mating and egg laying. A male may be able to claim a territory at the water for a day or two, but soon he loses possession, not in physical battle, but in a battle of aerial skills. Most adults live only a month or two, but the nymphs may live up to four years underwater!
According to field guides the methods odonates use to cool off are to perch in the shade, dunk in the water or obelisk. Obelisking is where the dragonfly appears to be doing handstands on the tips of twigs. They often perch right at the edge of a shadow, so temperature control is only a matter of moving inches.
Sometimes there's a mass migration of dragonflies. The phenomenon is not fully understood, but it may be that water conditions at a site may radically change, stimulating ecdysis (nymphs turning to adults), and the new adults leave, searching for new habitat.
There are stories about occasions when at least 1000 Green Darners gathered in the trees around a house of some West Texas naturalists. They reported that the dragonflies remained active after dark, coming to the porch light to capture moths. Some even came into the house.
The nymphs are fascinating. Spider-like, they wait for their prey without moving. then their lower jaw unhinges and swings out with lightening speed to capture prey as big as tadpoles and minnows. They possess gills in their anal opening, sucking water up and in, then expelling it - sometimes expelling it explosively so that the nymph becomes jet propelled.
Some species can be identified by their habits: One spends its time whirling in big circles over the water, another patrols a small circle, a third species spends most of its time hovering less than two feet above the water and still another spends the afternoon flying around the tops of trees. What wondrous complexities the natural world has evolved! Researching odonates is intriguing often surprising, and amazing. One thing's for sure - it's not boring.
Nature Notes is sponsored by the Dixon Water Foundation and is produced by KRTS Marfa Public Radio in cooperation with the Sibley Nature Center in Midland, Texas. This episode was written by Burr Williams of the Sibley Nature Center.