Comet Darners (Anax longipes) are in the dragonfly family Aeshnidae, the darners, and in the genus Anax, a group of large and sometimes migratory darners (Anax comes from an Ancient Greek word meaning “lord,” “master,” or “king”).  Bugguide.net shows four other genus members in the US, a couple of them just barely here:

The Amazon Darner – https://bugguide.net/node/view/240386/bgimage;

The Giant Darner – https://bugguide.net/node/view/566371/bgimage;

The Blue-spotted Comet – https://bugguide.net/node/view/867345/bgpage; and the

Common Green Darner https://bugguide.net/node/view/2042845/bgimage.   

Comet Darners mostly live east of the Great Plains, from Florida to Ontario, though they are distributed randomly, and even though they aren’t officially considered migratory, they are strong flyers that can end up just about anywhere.  They prefer relatively shallow ponds with forested edges, lots of floating, submerged, and emergent vegetation, and few/no fish.  The water level of many of their chosen ponds fluctuates annually. 

Comet Darners are fast and impressive, and with a wingspread of up to 3 ½” (females are slightly larger than males) they are among our largest dragonflies,  And at 2 ½” long, their naiads are pretty big, too – Freda’s photograph of the empty shells of a Comet Darner (left) and Common Green Darner (right) show the size difference.  They have long, spectacular red and black legs https://bugguide.net/node/view/88077, and males have a constriction on the third abdominal segment that gives them a “narrow waisted” appearance (females are stockier).  The male’s red abdomen fairly glows as he flashes by https://bugguide.net/node/view/1865911/bgimage.  Females have pale spots on their abdomen https://bugguide.net/node/view/218411/bgimage.  They seldom perch and are hard both to catch and hard to photograph (bugguide.net has a surprisingly small collection of pictures for a dragonfly this flashy, with this large a range).  Some observers report that these darners are most active in the beginning and ending parts of the day. 

Most sources say that the only dragonfly you might mistake the uncommon Comet Darner for is the smaller Common Green Darner (which is, as its name suggests, common). The BugLady got pretty excited when she spotted the colorful darner perched in the grass, but despite the red abdomen, she could see the Cyclops eye on the top of its head when she photographed it – an especially colorful female Common Green Darner.  Comet darners lack that “bulls-eye” on the face https://bugguide.net/node/view/125199/bgimage. 

Like all Odonates, Comet Darners are carnivores, both during their aquatic youth as naiads and as aerial adults.  The naiads are big enough to tackle not only the usual aquatic invertebrates but also small vertebrates like minnows, tadpoles, and frogs, and they’re top predators in their habitats.  Adults cruise about 8 feet above the water, grabbing insects out of the air, and their super-long legs allow them to go after larger prey, including their fellow dragonflies.  On the Comet Darner page of his great “Dragonflies of Northern Virginia” website, Kevin Munroe writes “I saw one flying off to feed in the trees with two Black Saddlebags (decent-sized insects themselves), clutched tightly in those long, red, black-hooked legs. I guess he was hungry, and one dragonfly just wasn’t enough.”

Males are territorial, patrolling all around the shoreline of their pond, just above the level of the vegetation, looking for food, intruders, and mates.  Neither males nor females are monogamous.  Females slice into the stems of plants just below the water’s surface with their ovipositor and insert eggs https://bugguide.net/node/view/1835467/bgimage.  Eggs hatch within a month, but the naiad/immature stage may last for several years.

According to the Comer Darner page on the Massachusetts Natural Heritage and Endangered Species website, when they emerge https://bugguide.net/node/view/1321893/bgimage, “Immature dragonflies may spend a week or more feeding and maturing away from water, often some distance from the breeding site.  Comet Darners are rarely seen during this stage.  It is possible that they spend their time in the tree tops, where they are difficult to observe.  …….  When at rest, they hang from the vegetation in a vertical position, often high in the trees.”  

What’s their status in Wisconsin?  Are there unchecked ponds out there that are graced by Comet Darner flyovers every summer?  Are there Comet Darner naiads under the ice in Wisconsin right now, awaiting the warming waters of spring?

Comet Darners are listed on the Wisconsin Odonata Survey website as a “Most Wanted” species, and their story here is similar to their story in other states at/beyond the edges of their range.  

In his article called “What is the incomparable Anax longipes (Comet Darner) doing in Wisconsin?” Robert DuBois and Freda trace the history of Comet Darners in the state. Beginning with a report in 1978, Comet Darners have been recorded at just a few sites in just a few counties.  They have not been seen every year, and while most sightings are of males, ovipositing females have been seen, and an exuvia (shed skin) of an emerged naiad was found at one site, pointing to successful breeding. 

There are tantalizingly few reports here each year (a Comet Darner was recorded during the 2024 Riveredge Butterfly and Dragonfly Count), but some sites have been visited multiple times.  Sometimes, individuals are seen for a few days and then they disappear, but other Comet Darners are observed on ponds for longer stretches of time.  Data collected in Wisconsin and in Michigan suggest that, while it is possible that random wandering individuals could find the same pond several years in a row (remember, dragonflies only live a few months as adults, so they’re not revisiting a site, like migratory birds), it’s more likely that small numbers of Comet Darners are breeding in Wisconsin, at the northwest edge of their range – what Robert DuBois calls “small but persistent interacting subpopulations.”  

Fun Fact about Darners:  In his book Dragonflies of the North Woods, Kurt Mead says, “Not to scare you, but I have heard of rare, isolated reports of darners attempting to lay eggs into human skin. One scientist carefully observed eggs being injected into each cut in his skin.  Perhaps this phenomenon is the source of some old European names such as ‘eye sticker,’ ‘horse stinger,’ and ‘devil’s darning needle.’”  (to which the BugLady replies 1) of course he did; 2) that scientist doomed those eggs in service of his useless observation; and 3) the devil takes the fall for a bunch of stinging and scary-looking insects.).

Kate Redmond, The BugLady

Bug of the Week archives:
http://uwm.edu/field-station/category/bug-of-the-week/