CRITTER SPOTLIGHT: Darner Dragonfly: Anax junius
Good Morning Watershed Explorers,
I hope you all had a wonderful week, happy second day of spring! The signs are here. Birds are chirping, frogs are peeping, insects are flying about, and "fluffy" our infamous squirrel friend has resumed his acrobatic stylings to lunge into our window bird feeder. Signs of spring have also returned to the water. On Monday afternoon, my daughters and I found some caddisfly larvae in a stream at the Arcadia Management Area in West Greenwich, RI. Here are pictures of "fluffy" and the caddisfly for your viewing pleasure.
Today's feature critter is one of my favorites, the green darner dragonfly, Anax junius. This is the last critter spotlight that features one of the five critters that Watershed Explorers complete a critter study poster on each year. If you are interested in creating a critter study poster, the requirements are on this website under the critter project tab. One of the project requirements is to create a song, poem, or rap about your critter. If you would like to try it, I would love to hear some of your creations and even post them on a future blog or the website. Under the same critter project tab, you can check out some of the posters that students from previous years created.
The common green darner dragonfly, like all dragonfly species, starts its life underwater as a nymph. Nymphs are dragonfly babies. Here is a photograph of a green darner dragonfly nymph that I found at Frosty Hollow Pond in West Greenwich, RI. This photograph is perfect for showing the details of this amazing insect. You can see the head, thorax, abdomen, and six legs perfectly. Dragonflies also have huge eyes which are important for tracking down prey.
Green darner dragonfly nymphs and adults are carnivores. They are incredible hunters. They feed mostly on other insects. Nymphs will also feed on other aquatic creatures like tadpoles, larval salamanders, and fish. In water bodies where there are no fish, green darner dragonfly nymphs are considered a top predator. They will often feed on other dragonfly nymphs that are smaller than themselves. If no other food is present, green darners have been known to cannibalize.
Here is a graphic showing the life cycle of a dragonfly. Dragonfly nymphs do not have a pupal stage and therefore shed their exoskeleton several times before turning into an adult dragonfly with wings.
Some dragonfly nymphs can survive the winter in their aquatic habitat and will go several years before completing their metamorphosis into an adult. Once the dragonfly completes metamorphosis, however, it cannot survive the cold weather and will die sometime late fall, early winter when temperatures drop.
Anax junius plays an important role in the watershed ecosystem. Not only does this dragonfly rid the watershed of insects that are harmful to humans, and provide food for other watershed animals, but it is a fantastic water quality indicator. The common green darner is a species of dragonfly that requires healthy water for survival. Finding the common green darner in a watershed area tells scientists that the water has fair to excellent water quality.
Dragonflies are amazing flyers. The green darner can reach speeds up to 35 miles per hour and is considered by most scientists, the fastest flying insect. Dragonflies can also stop, hover, fly backward, and even upside down. Scientists describe them as arial wizards.
I hope you enjoyed learning about the common green darner dragonfly, Anax junius. If you have any questions or comments, please email email@example.com