Rusty Snaketail (Ophiogomphus rupinsulensis) female perched near the South Branch of the Kishwaukee River, Cherry Valley, Illinois, 42°11'51"N 88°57'58.6"W, 28 May 2018. Photo: Joyce Gibbons
April Species of the Month
Rusty Snaketail (Ophiogomphus rupinsulensis)
DSA’s April “Species of the Month” is the Rusty Snaketail (Ophiogomphus rupinsulensis), a dragonfly in the Clubtail family, Gomphidae. The Rusty Snaketail is 45-54 mm (about 1.7 to just over two inches) in length. Its range generally encompasses the upper Midwest and Northeast into southern Canada. Follow the journey of Illinois Environmental Protection Agency Specialist and committed volunteer Joyce Gibbons as she seeks out this favorite species of hers in the rivers of north-central Illinois.
Seeking Out Snaketails
The aptly named Snaketails of the genus Ophiogomphus are an intriguing group of dragonflies that, with imagination, appear snake-like, given the pattern of their abdomens and the shape of their clubs. In fact, the term Ophio is Latin for serpent. Members of this group generally inhabit pristine rivers and streams and can be quite localized and uncommon, making them especially fun for ode enthusiasts such as myself to find and photograph.
Rusty Snaketail (Ophiogomphus rupinsulensis) female perched near the South Branch of the Kishwaukee River, Cherry Valley, Illinois, 42°11'51.0"N 88°57'59"W, 28 May 2018. Photo: Joyce Gibbons
Nineteen species of Ophiogomphus are present in North America, but only one species occurs (so far) in my home state of Illinois: Ophiogomphus rupinsulensis, the Rusty Snaketail. Apparently, it is more tolerant of silt and disturbance than most of its Snaketail cousins. Luckily for Illinois, not necessarily known for its pristine rivers, the Rusty Snaketail has found suitable habitat here. It is a favorite of mine as it is the first dragonfly that I observed when I started my now decade-long journey monitoring dragonflies.
An adult Rusty Snaketail is beautifully colored with a light green face, bluish-green eyes, apple-green thorax and a golden-washed, striped abdomen. The brown thoracic stripes prominent on other members of this genus appear fainter on the Rusty Snaketail. The club is tinged with russet, giving the species the “Rusty” part of its common name. I can envision the rather “kinked” club at the tip of the male’s abdomen as a snake rearing its head. The nymphs are ambush predators, burrowing down in gravelly or sandy substrates of larger streams and rivers.
Note the snakelike appearance of the abdomen of this Rusty Snaketail (Ophiogomphus rupinsulensis) male perched at the edge of a prairie restoration in Deer Run Forest Preserve, Cherry Valley, Illinois, 42°12'44"N 88°58'09"W, 3 June 2018. Photo: Joyce Gibbons
My initial spotting of a Rusty Snaketail was on May 31, 2015, while walking my first route as a volunteer dragonfly monitor for the local county forest preserve district. Although fascinated by dragonflies since graduate school, and somewhat versed in insect taxonomy, I had not studied the identification of Odonates. That changed very rapidly! At the time, though, I was frustratingly unable to identify the dragonfly that I had briefly spotted perched in a stand of reed canary grass (don’t get me started on reed canary grass!). But an expert in Illinois was able to do so based on the one photograph I had managed to take before it quickly flew off. (On a side note, my Ode “stalking” has greatly improved since then.)
I later realized that the species had not been found in my county and was considered critically endangered in Illinois, although common in Wisconsin, my neighbor to the north (a state which—yes, I’m jealous—boasts seven Snaketails).
During the next few years, as I continued my volunteer work, I was able to observe and photograph this species on numerous occasions, often, though, with several years between sightings. In my neck of the woods in far north-central Illinois, one must be persistent and spend long hours to have a chance of finding anything other than the most common Odonate species.
First observation of a Rusty Snaketail (Ophiogomphus rupinsulensis) in Winnebago County, Illinois. This male was perched in a stand of Reed Canary Grass (Phalaris arundinacea) along the bank of the South Branch Kishwaukee River, Cherry Valley, Illinois, 42°11'55"N 88°57'40"W, 31 May 2015. Photo: Joyce Gibbons.
My only sightings of the Rusty Snaketail have been in areas within the Kishwaukee River Watershed, where some of the few higher quality rivers and streams flow in the state. Adults begin emerging here in mid-May. I have encountered Rusty Snaketail exuviae attached to riverbank vegetation in positions less than an inch above the sand/silt (and sometimes still touching the sand!) and just a few inches from the water’s edge. I’ve also found them approximately two feet directly above the water on bridge supports.
A Rusty Snaketail (Ophiogomphus rupinsulensis) exuviae, still covered in sand, left by the emerged adult approximately one foot from the edge of the Kishwaukee River in Blackhawk Springs Forest Preserve, Cherry Valley, Illinois, 42°12'06"N 88°58'49"W, 18 May 2024. Photo: Joyce Gibbons
Through early June, I’ve seen recently emerged adults with wings still glistening perched in dense patches of high grasses along riverbanks. The bright green head and thorax and the muted abdominal coloration of these newly emerged adults provide excellent camouflage in the grasses, allowing them to blend into their surroundings during this vulnerable period.
A recently emerged Rusty Snaketail (Ophiogomphus rupinsulensis) female, whose coloration is not fully developed, is well camouflaged among the Kishwaukee River shoreline vegetation, Cherry Valley, Illinois, 42°12'07"N 88°58'49"W, 22 May 2023. Photo: Joyce Gibbons
In my experience, to find prey, the maturing adults head to areas of restored prairie within the forest preserves they inhabit. I’ve observed them position themselves very low in the prairie vegetation, fly up vertically to grab prey, and then float straight back down to their original position.
Once fully mature and ready to mate, the males head to the river. According to many sources, the males prefer to perch on rocks and boulders midstream or on sandbars. All my observations of mature males at the river have been of those perched on sandbars of the South Branch of the Kishwaukee River, perhaps because this shallower river with few large rocks or boulders is easier for me to navigate on foot! Bias acknowledged.
A male Rusty Snaketail (Ophiogomphus rupinsulensis) perched on a sandbar in the South Branch Kishwaukee River. Two other males took up positions nearby, Cherry Valley, Illinois, 42°12'01"N 88°58'31"W, 10 June 2017. Photo: Joyce Gibbons
On an early June day at noon, as I walked a path skirting a prairie/woods interface, a wheeled pair flew in front of me across the path and landed at head height in a shrub at the edge of the woods, about 750 feet from the river. They remained perched in the same vertical position on this shrub for over 15 minutes. They were still there when I finally forced myself to leave them and move on along the path. I have yet to see a female at the river and so have not observed female oviposition behavior.
A Rusty Snaketail (Ophiogomphus rupinsulensis) mating pair in wheel at the edge of a floodplain forest, Cherry Valley, Illinois, 42°11'57"N 88°58'07"W, 10 June 2017. Photo: Joyce Gibbons
Rusty Snaketails keep good company, at least from an ode enthusiasts point of view. It seems that the specific spots along the Kishwaukee River and the South Branch of the Kishwaukee River where I have observed Rusty Snaketail adult males and exuviae are also favorite haunts of other fun-to-spot dragonfly species, including Cobra (Gomphurus vastus), Midland (G. fraternus), and Plains Clubtails (G. externus). In early August, at one particular bend of the South Branch of the Kishwaukee River, near a sandbar favored earlier in the summer by Rusty Snaketail males, I consistently see Riverine Clubtails (Stylurus amnicola), Arrow Clubtails (S. spiniceps), Swift River Cruisers (Macromia illinoiensis), and Fawn Darners (Boyeria vinosa) flying.
A male Cobra Clubtail (Gomphurus vastus) perched on Brambles (Rubus sp.) a few feet from the male Rusty Snaketail (Ophiogomphus rupinsulensis) pictured in Photo #2, Cherry Valley, Illinois, 42°12'44"N 88°58'09"W, 3 June 2018. Photo: Joyce Gibbons
A female Midland Clubtail (Gomphurus fraternus) perched a few yards from the male Rusty Snaketail (Ophiogomphus rupinsulensis) pictured in Photo #3, Cherry Valley, Illinois, 42°11'55"N 88°57'40"W, 31 May 2015. Photo: Joyce Gibbons
As ode enthusiasts grow in numbers, so does the species distribution data. Since my first spotting of the Rusty Snaketail a decade ago that jump started my ode chasing hobby, the Rusty Snaketail’s status in Illinois has been recently upgraded from “critically imperiled” to “rare or uncommon” thanks to additional reported sightings. That’s a good thing! But I guess I’ll still have to head north to neighboring Wisconsin if I want to spot any of its Snaketail cousins. For the time being, anyway!
Our guest blogger is Joyce Gibbons from Rockford, Illinois. She holds a Bachelor of Science degree from Murray State University and a Master of Science degree from the University of Wisconsin-Madison. She is currently employed as a supervisor of a field office of the Illinois Environmental Protection Agency. In her free time, she enjoys volunteering, writing articles, and giving dragonfly talks for various non-profit conservation organizations, including The Nature Conservancy and The Natural Land Institute. She has volunteered for the U.S. Fish and Wildlife Service, Illinois Department of Natural Resources, Wisconsin Department of Natural Resources, Beloit College, Boone County Conservation District, and McHenry County Conservation District seeking out and finding newly discovered populations of the federally endangered Hine’s Emerald Dragonfly (Somatochlora hineana). She is a long-time dragonfly monitor for Nachusa Grasslands in Franklin Grove, Illinois, and she also dabbles in bumble bee, bat, and frog monitoring for the Winnebago County Forest Preserve District. Reach her at gibbonsx6@comcast.net.