By Marian McKenna
It’s time for Field Notes, brought to you by the Montana Natural History Center.
It is not every day that you share a lunch moment with a beautiful insect. It was an unseasonably warm spring day in western Montana. I was between the horse barn and the chicken coop on a bright morning in the Blackfoot Valley. I was sweating, which I think was the primary attraction for the dragonfly who landed on my wrist.
I froze in place, wanting to get a good look at this iridescent winged marvel. She had a live fly in her grasp and proceeded to devour the hapless creature from her perch on my wrist. I could feel her six legs balancing her perch and prey. It was fascinating as well as horrifying. The dragonfly was a winged terminator—ferocious and efficient. That fly went down her gullet to the very last leg. Meal finished, my voracious visitor took a bit more salt from my wrist and sped off to hunt again. A sheer delight that lasted but seconds.
This moment with the dragonfly piqued my curiosity. Do they actually have gullets? Do they come in male and female? When I was first learning the names of these delightful insects, I was sure that all dragonflies were males and damselflies were females. Time to find answers.
Dragonflies are in the order Odonata, which in Greek means “toothed one.” They share this order with damselflies, although they belong to different suborders. In Montana we’ve identified 59 dragonfly species and 34 species of damselflies—to date. Damselflies are smaller and more delicate than the dragonfly, and their compound eyes are separated on their head, rather than meeting together on the top of their heads. At rest, dragonflies hold their wings out like a glider. The damselfly folds her wings along her body. However, both suborders have male and female members, nomenclature notwithstanding.
Dragonflies spend most of their lives in the air. They even mate in the air. As the male bends to the female to deposit his sperm, they become one flying unit. Romantics say this configuration looks like a heart. The female deposits her fertilized eggs in fresh water, be it a lake, stream, bog, or swamp. Underwater, the larvae begin their predacious life, eating insects and small fish.
Once mature, the larvae climb out of the water, usually at night, find a branch to cling to, and break out of their exoskeleton, emerging as a full adult. It takes several hours for the body and wings of the adult to harden into the fearsome hunter we know. The dragonfly is the most ferocious and successful predator in the animal kingdom. They are successful in their hunts 90-97 percent of the time. In contrast, wolves are successful in their hunts often less than 20 percent of the time.
If you are ever lucky enough to catch sight of a dragonfly with the sun reflecting on its wings, you will notice their complicated veining and spectacular iridescence. The configuration of these four beautiful wings allows for the incredible dexterity of their flight. Dragonflies are able to fly up, down, forward, and backward. They are extremely fast, darting through the air. The four wings are separately attached to the thorax, allowing the muscles of each wing to operate independently. Further contributing to their hunting success rate, dragonflies have the ability to predict where their prey are going and intercept them on the wing, holding on to them with their serrated mandibles—earning that toothed description.
They do have mouth parts into which the mosquito or fly disappears. Technically, then, dragonflies do have gullets, though their digestive system is rarely, if ever, referred to as such. Either way, I am grateful for the work dragonflies do in keeping down the mosquito and fly populations.
I felt an affinity with the dragonfly, that warm spring day. Catching sight of them, our ferocious, winged ballerinas, is breathtaking.
Today’s Field Note was written in the Field Notes Writing Workshop at the Montana Natural History Center. I’m Marian McKenna for Field Notes, brought to you by the Montana Natural History Center, providing natural history education for schools and the public throughout Montana. For information on upcoming events and programs at the Center, call 406.327.0405 or visit our website at MontanaNaturalist.org.
