2026

The BugLady checked the (highly searchable) website of the Wisconsin Odonata Survey () to see if anyone had reported a Common Green Darner yet.ÌıThey are early migrants from the southeastern part of the country, traveling north with the warm weather, and they’re often the first dragonfly species of the year.ÌıHere’s an episode about them from nine years ago.ÌıNew pictures, a few new words.Ìı

2017

A Common Green Darner was reported near La Crosse (WI) on March 24 of this year, and a few others have been seen since then (and even though the winter of 2016-17 has been “Winter Lite,� the BugLady is ready for spring and dragonflies). The BugLady wrote very brief biographies of the green darner in 2010, in BOTWs about spring dragonflies and about dragonfly swarms, but there’s much more to the Common Green Darner story.

They are in the darner family Aeshnidae, a group of large, powerful dragonflies (“darnerâ€� because their long, darning needle-like abdomen has led to folk tales about their sewing people’s lips or ears shut). 

Most of our Wisconsin darners are in the famously-confusing mosaic darner genus Aeshna.ÌıCommon Green Darners (Anax junia) (“Lord of Juneâ€�) are one of two species of Anax darners found in the state.ÌıCommon Green Darners are, well, very common, not just here but across the country.ÌıAnd Central America. And Hawai’i.ÌıAnd Canada. And there are populations in Tahiti and the West Indies.ÌıAnd strong winds have blown individuals to Great Britain, China, and Russia.ÌıThe other Anax, the stunning Comet Darner (Anax longipes) is a rare visitor and even rarer breeder in Wisconsin .  

Common Green Darners are big, with a 3â€� long body and a 3 ½â€� wingspan, and their striking “wrap-aroundâ€� compound eyes may be made up of as many as 50,000 simple eyes apiece.ÌıTheir wings often show a golden tinge in flight. They practice sexual dimorphism – both males and females have a green thorax, but males have a predominantly blue abdomen with a purple stripe, and females have a maroon/rust-colored abdomen with a darker stripe.ÌıTenerals (newly-emerged adults) may take a week or more to solidify their adult color patterns and have female-ish coloration in the interim, and a chilly darner is a darker-colored darner.ÌıBoth males and females have prominent cerci (claspers) at the abdomen’s tip.ÌıCommon Green Darners have a characteristic bull’s-eye spot on their “foreheadâ€� that Comet Darners lack. They can move each wing independently, which lets them hover, and even fly backwards.ÌıThey perch vertically, frequently in low vegetation, so they usually spot the BugLady long before she spots them.Ìı

The long, slim, immature green darners (naiads) are found in still or very slowly-moving, shallow waters, preferably without sunfish and bass (nice set of naiad pictures here ).ÌıAdults frequent the air above those habitats but may be seen far from water.Ìı

Two populations of common green darners – one migratory, the other resident – form tag teams in the air over Wisconsin.ÌıMigrants from the south arrive early, often in late April, as their prey (small, aerial insects) start to appear. They are the offspring, or the offspring’s offspring, of the darners that flew south in the fall (no, they apparently do not return to their natal ponds). “Shiveringâ€� their wing muscles to heat up the thorax allows them to be active in cool weather, and they also bask in the sun.Ìı This is so effective that temperatures as high as 110 degrees have been measured inside the thorax (which challenges the whole definition of cold-bloodedness).ÌıThe picture of the female with the battered wings was taken in early July, suggesting that she was a migratory female who was reaching the end of her trail.Ìı

The migrants mate and die by early summer, leaving their eggs in the water, just as the naiads of the resident population emerge as adults, leaving their empty shells (exuviae) on shoreline vegetation.ÌıThese residents live a month or two as adults, depositing their eggs in late summer as the migrant adults emerge.ÌıResident naiads overwinter under the ice in a state of suspended animation called diapause and take 10 or 11 months to mature (possibly more, in the chilly waters “Up Northâ€�), while the migrant naiads need less than half that time in the warm waters of summer.Ìı

Mating commences when a male clasps a female at the back of her head in mid-air (one source said that she can reject his advances), and then they retire to a perch to mate.ÌıFemales oviposit in the open, in woody and herbaceous plant material below the water’s surface, with the male typically retaining his grip on her head.Ìı

The books say that these are the only darners that oviposit in tandem.ÌıThe books also say that a couple flying in tandem may be strafed by rival males.ÌıThe attendant male doesn’t have many options; he may flap his wings at the intruder, shake his abdomen, land in vegetation, and even bite his challenger.ÌıAccording to Paulson, in Dragonflies and Damselflies of the East, females may curl their abdomen under and close their wings when under attack.ÌıThe BugLady once photographed (badly) an unattached male as he dive-bombed a second male whose abdomen was deeply submerged (presumably with an ovipositing female at the other end of it).Ìı

The BugLady once found a female stuck in an especially dense and sticky, dragonfly-eating patch of blanket algae.ÌıDid the female attempt to perch on the algae as she oviposited and get her wings stuck, only to be abandoned by her mate? Or, alternatively, did she get thirsty and then get stuck? Dragonflies “drinkâ€� by immersing their abdomen – water enters through the exoskeleton (the BugLady was able to fish her out with a stick).Ìı

The naiads are active predators that will eat anything they can grab using their foldable “lower lipâ€� (labium) – zooplankton, other aquatic insects (including dragonfly naiads), tadpoles, larval salamanders, and fish fry are all fair game.ÌıIn his wonderful write-up of the Common Green Darner, Kurt Mead (Dragonflies of the North Woods) muses that “If dragonfly larvae were eight to sixteen inches long, as they probably were 300 million years ago, we would dare not swim in fresh water for fear of being attackedâ€� (read the whole account at ) (there was a lot of oxygen in the atmosphere in those days, and some invertebrates grew to lunker size). Despite their spiny exteriors and their ability to shoot forward by expelling a spurt of water forcefully from the rear of their abdomen, they are eaten by frogs, fish, and by other aquatic insects. There’s even an “aquaticâ€� parasitic wasp that lays its eggs in those of the green darner – Aprostocetus polynemae apparently walks down a twig or leaf stem into the water to find dragonfly eggs.Ìı

Adults catch insects in the air and may eat them in mid-flight or on a perch.ÌıThey can also pick prey from a leaf or from the ground, and they’ve been known to stake out bee hives, to the distress of the bee-keeper.ÌıAt least one ambitious Common Green Darner killed a hummingbird, and this fact is mentioned in every darner write-up, though the BugLady suspects it’s pretty uncommon. Adults are preyed on by robber flies, birds, spiders, and by other dragonflies; the people who monitor the fall raptor migration tell us that the southward movement of American Kestrels syncs with that of the darners, and that kestrel migration is fueled by darners.Ìı

So, Common Green Darners migrate. Like birds, they respond to a suitable weather front – cold fronts for the southern flight and warm fronts for the far less conspicuous northern trip.ÌıThe journey south may take several weeks of stop-and-start flying (averaging 7 miles a day but capable of far more, depending on the wind), and they may be accompanied by black saddlebags and variegated meadowhawk dragonflies.ÌıLate summer/fall migration is dramatic, huge swarms may take hours or days to pass a fixed point.ÌıBluffs on the west edge of Lake Michigan are great places to catch the show at eye level.Ìı

The Common Green Darner is the State Insect of Washington – so much more exciting than Wisconsin’s honeybee (and you thought the state insect was the mosquito!).Ìı 

As always, don’t eat them – they carry parasites.Ìı

Unfinished business – in response to the recent BOTW about deer flies, a few French scholars pointed out to the BugLady that she had misspelled the term “je ne sais quoiâ€� as “jean es se qua.â€� She had consulted Monsieur Google about the correct spelling, and she had, alas, believed him.Ìı

The BugLady 

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Greetings, BugFans,

The dragonfly season is starting – migrant Common Green Darners and  are filtering into the state, and visions of sugarplums (in the form of Chalk-fronted Corporals, Baskettails, and Eastern Forktails) are dancing in our heads! June will see the first of the Emeralds (family Corduliidae).Ìı

Also called Green-eyed Skimmers (though the name Skimmer belongs more properly to a different family, Libellulidae), the Emerald family is a large and varied one (about 50 species in North America and 400 worldwide) that includes the bog haunters, emeralds, baskettails, sundragons, and shadowdragons.ÌıCorduliids are found worldwide, and as a group, their ranges tend to be northerly.Ìı

They are medium to large (1 ½â€� to 3â€� long) dragonflies, and although they may be dark in coloration, many have metallic markings on their thorax and . Many species have a pale ring between the second and third abdominal segments. When they perch (which is not often enough for dragonfly photographers), they tend to perch vertically, hanging from vegetation at a 45 degree angle.Ìı

Every spring, the BugLady takes lots of pictures of the very spiffy , a species found commonly in the northeast quadrant of the continent.ÌıShe doesn’t see the larger, American Emerald (Cordulia shurtleffii) nearly as often – it’s more common near bogs, sedge marshes, forested lakes and ponds, and fens “Up Northâ€� and across much of Canada and the northern US.ÌıSome American Emeralds have (slightly) flared abdomens, like the Racket-tailed Emerald does, but the yellow band at the top of the Racket-tail’s abdomen is thick and uneven compared to the .Ìı may resemble and overlap in size with some of the Striped Emeralds in the genus Somatochlora.  

Adults eat soft-bodied insects that they grab out of the air, from mosquitoes to butterflies to mayflies to royal ants to recently-emerged dragonflies and damselflies. They forage in woodland openings and edges and sometimes, early in the season, mingle with swarms of baskettails.ÌıPaulson (Dragonflies and Damselflies of the East) reports that the American Emerald “sometimes hovers among plants in an effort to flush prey, often successful.â€� As befits a northern species, they are more active in cooler temperatures.Ìı

Kurt Mead, in Dragonflies of the North Woods, tells us to “Look for the males’ ‘dart and hover,’ ‘dart and hover’ behavior as they patrol their shifting territories along boggy edges of small lakes and ponds.�  After , a longish process carried out partially in flight, Mead says that “the female taps the surface of the water with her abdomen when laying eggs, often among sedges and other emergent vegetation.�  

The sturdy, hairy, aquatic naiads are “sprawlers,â€� hiding in the mud and under the debris trapped in their hairs, and ambushing their prey – scuds (freshwater shrimp), mosquito and midge larvae, mayfly nymphs, and the occasional tiny fish and tadpole – as it passes by.ÌıThey can tolerate pretty cold water, but in cold water they need more than one summer to mature.ÌıThey .ÌıHere’s a teneral – a recently emerged adult – that has the .

The BugLady was curious about the American Emerald’s species name shurtleffii (ah – the etymology of entomology!), so she did a little digging.ÌıThe species was described by the renowned entomologist Samuel Scudder in 1866. Scudder named it after a young physician named Carleton Atwood Shurtleff (1840 to 1864), a polymath whose interests included botany (native orchids) and entomology (he studied insect wing venation).ÌıShurtleff’s parents sent his collections and papers to the Boston Society of Natural History after his death in 1864 “from a disease contracted at the siege of Vicksburg.â€� Scudder read a paper by Shurtleff posthumously at a Society meeting and praised his achievements, and later immortalized him in a dragonfly’s name.Ìı   

Carpe diem (or as the BugLady’s t-shirt says, “Carpe Insectum.â€�)

The BugLady

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