More than seven years ago, I changed my gardening routine to a more organic approach and during this process, I became much more aware of the role beneficial insects play in my garden. At one time I believed the “only good bug was a dead bug,” but now I realize that many insects actually protect my plants, and I encourage them to call my garden home. A quote by Allison Mia Starcher hangs by my potting bench, “Assassin bugs in your lettuce patch? Rejoice!”
One of our most beautiful and beneficial insects is the dragonfly (order: Odonta, family: aeschnidae), and recently I’ve observed several bright orange-colored dragonflies flying about my garden. I always considered the dragonfly a beneficial insect and now I was inspired by their presence to find out more about them.
A true garden assassin, the dragonfly feeds on flies, gnats, mosquitoes and other small flying insects. In fact, most dragonflies will eat up to 50 mosquitoes a day. Unlike many insects, dragonflies are strictly carnivores and are not attracted to flowers and plants, although they are attracted to the insects that are attracted to flowers. With four dainty but powerful wings, the dragonfly is considered the world’s fastest flying insect, and unlike other winged insects it has great acrobatic mobility due to the fact that the front and back wings beat in opposite directions.
Studies show the dragonfly also possesses a flying technique that can produce an optical illusion that makes him look as though he is in a stationary position, therefore fooling his prey during aerial combat before he attacks.
Large, multifaceted eyes also assist the dragonfly in hunting and capturing his prey. Each eye has more than 30,000 light-sensing facets that are actually 30,000 tiny eyes within each eye. This unique eye structure allows them to detect the slightest movement and provides them with a 360-degree field of vision, even completely behind. I was able to get quite close to the dragonfly in my garden and observed his large eyes rotating around as he looked at me ” it was fascinating.
Recently, we added a small, shallow pond and a waterfall to our garden. Since several of my neighbors also have water features, this may be one of the reasons I am seeing more dragonflies, because they need water to reproduce.
The dragonfly’s life cycle begins when the female lays her eggs in water or near the water’s edge. Her eggs may be laid directly in the water or on aquatic or nearby grassy vegetation. After hatching, the baby dragonfly nymph lives underwater, where it will spend most of its life.
The tiny nymph does not resemble the adult dragonfly, and while underwater it will feed on tiny water creatures, especially its favorite meal, mosquito larvae. Depending on the species, the dragonfly’s nymph state can last from months to years, but once it takes flight, its lifespan will only last weeks to months.
The dragonfly’s metamorphosis is much like the butterfly or the story of the ugly duckling. The unattractive nymph climbs up out of the water and onto a reed or rock until the dragonfly emerges, with its beautiful, intricately webbed iridescent wings and eventually flies away. Black and colorless at first, after a few days to a week the adult dragonfly will begin to develop its dazzling color, which can range from bright hues of red, orange and golden to blue, green and purple. Many bear luminous stripes in contrasting colors down their long, slender bodies.
Dragonflies have inhabited the earth for more than 300 million years and have changed very little from their prehistoric form. The oldest fossilized dragonfly that has been found is said to be 320 million years old. More than 5,000 species of dragonflies call the earth their home, and in North America we have about 500 different species. Native North American Indians believed the dragonfly was the essence of the “winds of change” and that they brought with them prosperity and harmony.
Many of our world’s dragonflies are beginning to vanish due to deforestation, pesticides and pollution. Recently I read that a child dies of malaria every 30 seconds and I wondered why we are not doing more to encourage and protect this uniquely beautiful and valuable insect, since mosquitoes make up 90 percent of the dragonfly’s diet. By using pesticides to kill the mosquitoes, we also kill their natural predators, therefore upsetting the delicate balance of nature.