The cultural and ecological significance of urban gardens in Chicago
The oldest dragonfly fossil discovered was in Junggar Basin in Xinjiang Uygur Autonomous Region of China and is from the Late Triassic period (Xinhua, 2017). That's about 200 million years ago. One of its wings is almost 4 inches long.
Our dragonflies today are not so large, but one of the larger ones commonly seen in the Chicago area is the Common Green Darner (Anax junius). Its wingspan is about 3 inches, and its body length averages from 2.5-3.25 inches (Post, n.d.). This one below is a female. Males have bright blue on their abdomen. This beauty was observed in Englewood Veterans Garden across the street from Hermitage Community Garden while a celebration ceremony was taking place for its Founder and Director Cordia Pugh. The veterans were honoring her for establishing a garden specifically for them. The kids from Green Corps that worked inside of the gardens built benches, tables and helped with the maintenance of the garden. They told me that they saw many of these throughout the summer resting and flying overhead.
The other common dragonfly seen this summer was the Black saddlebag (Tramea lacerata). It is easy to identify because of the large black spots on its hind wings. From the air, these spots look like saddlebags. Notice its silhouette in the photo to the right. If you see this large dragonfly flying overhead and you do not notice a red hue, it is more than likely the Black saddlebag. This was one of many on several visits seen flying around the Edna White Century Garden. This one is a male. Females look similar but have yellow spots on their abdomen.
The second most common dragonfly observed so far was the male Blue dasher (Pachydiplax longipennis). Females have more of a golden brown with yellow streaks down the side of their abdomens.
These are often seen chasing each other. In this photo he is cooling himself on a squash leaf at Hello! Howard Garden where dozens have been observed at various times.
The Eastern Amberwing (Perithemis tenera) is another dragonfly often seen around Chicago. This cutey is a male. Females have spots on their wings. They are small but easy to notice because of their bright amber color.
In this photo, he is cooling himself in the prairie grasses at Pullman Community Garden on a hot summer day of 88 degrees Fahrenheit. The position that you see it in is called obelisking. This is done to prevent overheating.
This is not a complete listing of my dragonfly observations. This will come when the study is complete. It is continuing into September, but I am happy to report that dragonflies do indeed use the community gardens throughout Chicago.
In the meantime, if you spot one, we would love to hear about it. Please leave a comment and upload a photo if you have one. If you need a good field guide to help with identifying this mysteriously wonderful creature, please check out the Field Museum's Common Dragonflies and Damselflies guide (http://fieldguides.fieldmuseum.org/guides/guide/380).
Post, S. (n.d.) Common Green Darner Dragonfly. Illinois Natural History Survey, Prairie Research Institute. Retrieved from http://wwx.inhs.illinois.edu/outreach/spotlight/common-green-darner/.
Xinhuanet. (2017). 中科院团队发现2亿年前蜻蜓大如手掌. Retrieved from http://news.xinhuanet.com/tech/2017-06/15/c_1121149054.htm
Erratum: The Blue dasher photo was snapped at Hello! Howard Community Garden where dozens were seen in July and August. They were also seen at Cornell Oasis, but the photo in this post is from Hello! This was edited to indicate that on 12 August 2017 at 9:00am CST.