Damsel & the Dragon
Above: possibly a Thornbush Dasher (Micrathyria hagenii) dragonfly.
Below: possibly a Shadow Darner (Aeshna umbrosa
(Photos by Rachel Dressler)
Gliding through the air with swift and lethal acrobatics, dragonflies and damselflies are often admired for their grace. Some even think a visit from these flying friends is good luck or a message from a loved one. Beyond their obvious beauty and intrigue, their presence holds more than just symbolic significance.
Belonging to the order Odonata (meaning “toothed ones”), dragonflies (Anisoptera) and damselflies (Zygoptera) share many conspicuous features which distinguish them from other insects. Odonates have tiny antennae, very large eyes, long abdomens, two pairs of transparent wings, and extendible jaws. Perhaps surprisingly, odonates are also considered aquatic insects, as they spend most of their life in an aquatic larval stage. In fact, their larval stage can last from a typical 1-2 years up to 6 years, during which they molt 6-15 times! However, once they emerge from the water to complete their last molt, they skip a pupal stage, becoming an adult with functional wings. Talk about a rough puberty.
Overall, the distribution of odonates is highly variable. After spending their early life in the water, adult odonates are often found around bodies of water, such as marshes, rivers, or ponds depending on the species. Regardless, the presence of dragonflies and damselflies is a positive indication of ecosystem quality, though dragonflies are often more sensitive to pollution.
Odonates have a generalist diet, so they will eat whatever prey is most abundant; though their diet mostly consists of small insects. Humans consider damselflies and dragonflies to be friends as they feast on insects we consider pests (flies, gnats, mosquitoes, etc.).Their prehensile labium (extendible jaw under their head), swift flight, and legs like a claw machine make them lethal predators. However, this fierce aerial predator also falls prey to other species, such as birds, frogs, spiders, and fish. Yet, incredible visual acuity helps them to evade their predators-- more than 80% of their brain is used to process visual information!
You might be wondering, how can I tell the difference between damselflies and dragonflies? To list a few differences, damselflies are thin bodied, while dragonflies have stockier abdomens. Both pairs of damselflies’ wings are similar shapes, while dragonflies’ rear wings are larger than their front wings; as a result, dragonflies fly with more strength and precision. At rest, damselflies generally have their wings folded, while dragonflies have their wingspan extended as they lack the necessary hinges in their wings. Although this is oversimplified, there is an unfolding metaphor which can be used to easily remember how to differentiate the two. Damselflies are thin, delicate “damsels in distress,” while dragonflies are burly, winged dragons in the sky. Is this metaphor cheesy? Yes. Do I hope this helps you identify and appreciate these beauties in the sky? Also yes.
For more information, visit https://ucmp.berkeley.edu/arthropoda/uniramia/odonatoida.html.
Written by Faith Forry — October 7, 2020
