By Diana Dunn
Dazzling damselflies dancing through the air seem to be heralding the arrival of long summer days. However, these prehistoric looking insects do not always bear their lacy wings which enable them to dart around so effortlessly. Surprisingly enough, damselflies spend a portion of their lives wingless and underwater!
Damselflies are aquatic insects, and can be found living near the sun dappled waters of our local creeks. As nymphs, damselflies emerge from their eggs, which females slyly conceal in the tissue of riparian vegetation. During their underwater, adolescent phase damselflies have three flat, leaf-like appendages attached to the end of their abdomen. These delicate structures are gills used for breathing, and the larvae spread them apart like a paper fan to capture dissolved oxygen in the water.
The larvae are not strong swimmers and must find their way to still or slow moving water. Even though damselflies are not the most efficient at traveling through the water they are far from being fragile and meek creatures. Damselfly nymphs are fierce predators with a voracious appetite. Damselfly larvae are able to shoot their lower jaws out from their bodies at nearby prey. Spine-like structures at the end of the extended jaw capture an unsuspecting victim and sweep the target up into the mouth of the damselfly where it’s swallowed whole. When the prehensile jaw is not being used, it is tidily folded across the face of the damselfly nymph, and for this reason is known as its “mask.”
After ten long months of living, hunting and feeding in pools along the creek bank, damselfly nymphs will molt and become adults with their recognizable large, veined, translucent wings. Unlike their relatives, dragonflies, which hold their wings outstretched to the side of their long slender bodies; adult damselflies hold their wings together outstretched above their bodies. One other noticeable difference is that dragonflies are considered better flyers, but adult damselflies can be frighteningly quick in order to capture prey with their long, slender legs. These subtle characteristics can help creek-goers distinguish the difference between dragonflies and damselflies.
Not only are damselflies unique and exquisite looking insects, but their presence or absence in a riparian habitat is a wonderful indicator of creek health. If damselfly nymphs are found in the pools of local tributaries it typically means that the water quality is good in that creek. Damselfly nymphs can be sensitive to pollution if the amount of dissolved oxygen in the water decreases. Increased nutrients, like nitrate and phosphate, usually decrease oxygen levels in creek water. Most frequently, high nutrient levels in creeks can be attributed to fertilizer runoff or a leakage in septic systems. By taking preventative actions within our own homes, we can improve the overall health of our local creeks and watersheds and also enjoy the sight of iridescent damselflies zipping back and forth in the warm breeze.
To help support our efforts to restore local creeks for damselflies and other riparian species, CLICK HERE to DONATE.