by Mary Ellen Kelly
Stop by Sheldrake’s Goodlife Pond anytime soon and you will likely see damselflies and dragonflies hovering over the water and darting about the plants. But which one is a dragonfly, and which is a damselfly? How can you tell? Each insect belongs to the order Odonata. Common characteristics among odonates include large eyes, slender bodies, and wings that are translucent.
The easiest way to distinguish between a dragonfly and a damselfly is its wings. When resting, dragonflies keep their wings open and positioned horizontally, whereas damselflies keep them closed and pointed upward. And, if you can catch a glimpse of the two pairs on wings on each insect, you will notice that the wings on dragonflies are dissimilar, but those on the damselflies are the same.
At rest, you can also see that the dragonfly body is slightly larger with bodies that are sturdy and short. On the other hand, damselflies are a little smaller, with abdomens that are long and slender.
Common Skipper Dragonfly – Notice the stocky body and horizontal wings
Common Blue Damselfly – Thinner body and wings together, pointing upward
Another thing you may not have known about dragonflies and damselflies is that they both spend most of their lives in the pond, underwater, as nymphs. Just as on land, there are distinctions between these “cousins” as they mature.
A dragonfly nymph is stocky, with a short and bulky body. It is a vicious predator in the pond world – able to use its spring-like jaw to catch other insect nymphs, and even small fish and tadpoles! Dragonflies eat the larvae of other insects that live in the water, including mosquito larvae. One of the benefits of having dragonflies live nearby is that they eat many times their weight in mosquitoes every day. After about 15 molts, the nymph becomes an adult, which lives only about two to three weeks. Dragonfly nymphs can live underwater for a year or more before molting a flying insect.
Damselfly nymphs are long and slender, and resemble a mayfly nymph more closely than a dragonfly nymph. Damselfly nymphs become adults after several molts, and the adult has a relatively shorter lifetime compared to nymph.
If you are looking for a handy field guide to dragonflies and damselflies that you can bring to Sheldrake on your explorations, check out Stokes Beginners Guide to Dragonflies https://www.amazon.com/Stokes-Beginners-Guide-Dragonflies-Nikula/dp/0316816795/ref=sr_1_fkmr1_1?ie=UTF8&qid=1466444738&sr=8-1-fkmr1&keywords=stokes+beginning+guide+to+dragonflies
Or at Massachusetts Audubon, their pocket guide to Dragonflies and Damselflies http://www.massaudubon.org/about-us/services-products/audubon-shop/buyer-s-guides/pocket-guides