HOPKINS COUNTY, KY (12/7/12)—Over the past few weeks, thousands of unseen creatures, each with a remarkable pre-historic heritage, have crawled their way to the deepest depths of our area lakes, ponds, rivers, and streams. While submerged, these partially immature, bulbous-eyed life forms will cast a solemn, but watchful gaze into the murky nadir, hoping to seize their next meal. Yet, after months of near-frozen solitude, spring arrives and their staunch patience and survival instinct is fully rewarded, for it is only then that they shall return to the surface to complete their final transformation. What might this seemingly alien and sinister creature be, you ask? It’s none other than a common damselfly nymph.
Though they are somewhat similar in appearance to the dragonfly, undergo comparable life cycles and “incomplete” metamorphoses, inhabit much of the same territory throughout the US, and even share the prehistoric order-title of “Odonata,” damselflies are differentiated from their six-legged cousins in several different respects.
Along with being smaller in overall size, adult damselflies are usually seen more frequently around waterways than dragonflies—though they sometimes inhabit drier areas as well—and they even carry themselves in a different manner. Though each variation of the species differs in color, which can range all the way from neon blue to “rubyspot” red (see photos within this article), all damselflies are slender in build, with especial regard to their cylindrical abdomens. They also display large rounded eyes on both sides of their head. Whereas dragonflies’ wings remain outright and horizontal when at rest, a mature damselfly folds its four wings together when landing, which further enhances their thin, streamlined appearance.
But how has this ancient species survived all these years? The short answer is that one of their primary food sources is another prehistoric set of creatures we’d all be happy to see fewer of: the common, adult mosquito and their water-bound larvae.
The long answer is that damselflies begin life as an egg, which is deposited by a female in or near the edge of a body of water, such as a lake or stream. Soon after, a damselfly nymph that closely resembles an adult—minus a fully extended body and wings—emerges from the egg and remains underwater, where it will become quite a ferocious predator for its size. In addition to eating the wriggling, aquatic larvae of mosquitoes, they can also seize tadpoles and small minnows within their extended lower jaw. It is also during this relatively lengthy juvenile period that the nymph molts its skin a total of 10 to 12 times to accommodate growth.
Then, after what can become one to two years of remaining submerged, which depends on the species type, time of birth, and the weather, the nymph will make its way to warmer water where it will climb out onto dry vegetation. Here, the nymph will flex and strain until it breaks free from its own skin, leaving behind its gills and shell. Once the adult form has fully emerged, the newly transformed insect begins pumping bodily fluids into both its wings and abdomen until it is dry and ready for flight.
While adult, the insects skim over waterways and “sunbathe” on dry, warm surfaces. Using their compound eyes, which can register up to 28,000 facets at one time, a mature damselfly can target their minute prey—be it a mosquito, fly, or gnat—from up to 40 yards away. What’s more, their extreme, in-flight maneuverability, prehensile lower jaw, and spiny legs can easily prove fatal to an oblivious food source. Depending on the species, the adult damselfly will live for several weeks to several months before mating and dying.
And though the life of an adult is relatively short, the nymphs of the next generation will begin their migration to the deeper water in the late summer and fall, will undergo a period of hibernation, and will return to the shallow water the following spring to begin the process anew.
While the relatively diminutive damselflies of today are a far cry from their 300 million-year-old, fossilized parents, which have been found to have a wingspan of nearly three feet, their impact on our area’s environment is vast. From controlling the population of bothersome pests like mosquitoes, flies, and gnats, to providing a quick snack for fish, frogs, and birds, damselflies are an unsung hero of the animal world that, no doubt, will continue to further their existence for another million years.
To view more of the damselfly's life for yourself, click the video player attached below this article.