by Javier Gonzalez
One of the things I personally look forward to seeing as I walk the boardwalk in the hot summer months are dragonflies. Their colors and their flight movements are mesmerizing as they swoop around the wetlands, and to see one skim over the water and perch perfectly balanced at the end of a bare stick just gives me a great sense of peace for some reason.
Dragonflies are beneficial insects and indicator species that are symbolic of wetlands. They are extraordinarily designed and are able to fly in all directions and even hover in mid-air as they are capable of controlling each wing independently. They also have big compound eyes that let them see almost 360 degrees around them, powerful spiny legs that enclose their prey, and strong jaws to chew through exoskeletons and other tough food! These are just a couple of the amazing morphological traits that have made dragonflies extremely efficient and successful hunters on this earth for the past three million years!
When we see dragonflies around the wetlands here at the South Padre Island Birding & Nature Center, we take it as a sign that our habitat and water are healthy. Dragonflies are indicators of clean water; they cannot tolerate polluted waters, so dragonflies are reliant on healthy wetlands for survival and reproduction.
Before we see the colorful adults flying around, the larvae, called “nymphs,” are swimming underwater, preying like tiny dragons on mosquito larvae, other aquatic invertebrates, and even small fish and tadpoles! Most of a dragonfly’s life is spent in water as nymphs. Unlike a butterfly that has a 4-stage lifecycle, dragonflies only have a 3-stage lifecycle, or an incomplete metamorphosis.
Once they have eaten and grown enough, the nymphs crawl out of the water on emergent vegetation. This is where the last event in their metamorphosis takes place. They skip the pupa stage and go right from larvae to adult. Once the nymphs are out of the water, their exoskeleton cracks open from the back and the dragonfly emerges and unfolds as an adult. This usually happens in the early morning hours just before dawn. At this point the adult dragonfly is vulnerable to predators as it sits and waits for its wings and body to straighten up and harden so it may fly. Once they can fly they are formidable predators that are harmless to humans and extremely beneficial!
Dragonflies can eat 30-100 mosquitoes in a day, greatly reducing the population of these pesky and annoying insects that are potential vectors for different types of illnesses. Here at the birding center we’ve recorded more than 17 species! Most of the species we see here are “skimmer” types that come in a variety of bright colors and have some have really cool names like Eastern Pondhawk, Thornbush Dasher, and Variegated Meadowhawk!
|Seaside Dragonlet Dragonfly|
Since most dragonfly species can’t reproduce in water that’s highly saline, most of the dragonflies we see along the boardwalk are in greater numbers along our freshwater wetlands, but we do have one species which is special to our area and environment that we see quite frequently along the boardwalk which goes through our saltmarsh. The beautiful Seaside Dragonlet is the only North American dragonfly capable of reproducing in saltwater and one that you don’t see far inland away from the coast. This is a small dragonfly species and the males are a dark navy blue while the females are orange with black stripes. They are beautiful and a delight to see as they perch on the mangrove pneumatophore roots.
Late summer is the peak time for dragonflies and every week it seems like we are seeing new species and greater numbers! Come August they will be swarming around our wetlands! It is an incredible sight to behold!