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).��

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.��Corduliids are found worldwide, and as a group, their ranges tend to be northerly.��

They are medium to large (1 ½” to 3” 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.��

Every spring, the BugLady takes lots of pictures of the very spiffy , a species found commonly in the northeast quadrant of the continent.��She 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 North” and across much of Canada and the northern US.��Some 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 .�� 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.��Paulson (Dragonflies and Damselflies of the East) reports that the American Emerald “sometimes hovers among plants in an effort to flush prey, often successful.” As befits a northern species, they are more active in cooler temperatures.��

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,” 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.��They can tolerate pretty cold water, but in cold water they need more than one summer to mature.��They .��Here’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.��The 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).��Shurtleff’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.” Scudder read a paper by Shurtleff posthumously at a Society meeting and praised his achievements, and later immortalized him in a dragonfly’s name.��   

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

The BugLady

The post American Emerald Dragonfly appeared first on Field Station.

The BugLady thought it was time to give this episode from 2008 a make-over – many new words and pictures.

Mayflies, order Ephemeroptera (which means “short-lived wings”) are a large and complicated group, and because the BugLady has not learned the secret mayfly handshake yet, what follows is general information about the Order Ephemeroptera.�� Mayflies are not related to house flies (order Diptera). They’re considered to have some primitive insect characteristics, and fossil evidence tells us that they’ve been around since the Carboniferous Age (354 to 290 million years ago). Sources list 611 species in 21 families in North America (you can see physical differences in some of the mayflies pictured) and 3,350 worldwide.

Mayflies, aka lakeflies, willowflies, fishflies (though there’s a fishfly in the unrelated order Neuroptera), or shadflies (like shadbush flowers, they’re conspicuous in spring when the shad fish are spawning) have an interesting life cycle. Immature mayflies (naiads) are aquatic, growing up in (mostly) well-oxygenated, unpolluted streams and rivers, though there are species that favor shallow, still water. Adults are usually found at the edges of their natal wetlands. Depending on their family, naiads live under rocks, on the stream bottom, in tunnels, or on decaying submerged vegetation, at specific depths, and within specific ranges of dissolved oxygen. They are classified by their modes of locomotion as clingers, burrowers, sprawlers, crawlers, climbers, and swimmers, and one source calls them “microhabitat specialists.”

Most insects spend a disproportionate part of their lives as immatures, but mayflies take that to an extreme. Depending on water temperature and water quality, the egg stage can last as long as a year and the immature (naiad) stage for three years. Most adults live for three days, tops.
Although mayflies are most conspicuous in spring, some species are present in fall.�� Like cicadas, they practice what the BugLady calls the “Normandy Beach strategy of reproduction” – if you throw enough soldiers onto the beach, some will reach the beachhead (or, in the case of the mayfly, live long enough to mate). At their appointed time, mayflies emerge from the water, often at dawn or dusk, by the googol (more about that in a sec). Males form dense, dancing clouds in the calm air (they are fragile) above the water. Females fly in and pair up, and copulation is brief. Males may dance again the next day.

Female mayflies lay 500 to 3000 eggs, singly or in batches or all at once, placing them onto/under the water’s surface while in flight or from a perch on a rock, and some species crawl underwater to oviposit. The eggs sink to the bottom and go with the flow. Naiads are aquatic, living under water, feeding on algae and on tiny bits of organic debris delivered by the current (adults do not have functional mouthparts and do not feed – “ephemeral”). As they grow, naiads go through as many as two dozen molts (four times the number of molts that most insects with incomplete metamorphosis undertake).

Although they have external gills along the sides of their abdomen (the gills of species that live in still water are larger), naiads can usually absorb sufficient oxygen through their exoskeleton in well-oxygenated waters. They use their gills to keep the water moving over their body, and this mini-current also delivers food. Gills are used in low-oxygen situations.

When it’s time to emerge as adults, they have an unusual penultimate step. The naiad swims to the surface or floats up on an air bubble (one source said that the naiad empties its abdomen of digested food, replaces it with air, and “becomes” the air bubble!). It swims to shore and molts into a smoky-winged, not-quite-reproductively-mature subadult phase called a “sub-imago” or “dun.” A few minutes to a few hours later, it molts again into the final, clear-winged adult stage called the “imago.” The imago has longer “tails” for increased stability in flight and longer legs to grasp its mate. For photos of molting sequence, .�� Mayflies are the only insect that molts after reaching the winged, adult stage.

What can you mistake them for? Because they both fold their wings above their abdomen, adults might be confused with caddisflies, which also have aquatic immatures, but . Mayfly naiads are , but mayflies almost always have three “tails.” Stoneflies have two tails, and a stonefly’s gills are on its thorax.

And the Human-Mayfly Intersection?

First, as eggs, naiads and adults, mayflies are important strands of food webs in and around the water. Eggs and naiads are a favorite food for other aquatic insects, snails, crayfish, leeches, and fish, and adults are eaten by birds, bats, dragonflies, spiders, frogs, and shrews. Since mayflies are relished by trout, fly fisherpeople (and bait manufacturers) go to a good deal of effort to keep track of what’s emerging and to tie flies that “match the hatch.”
Second, mayflies are sensitive to changes in water quality and are indicators of clean water. Like many other insects, their numbers are declining, most notably due to water pollution.

Finally, those dramatic, synchronized emergences of zillions of adults are cause for some lakeside and river communities to call in the snowplows in summer as the mayflies’ slippery bodies impair visibility and cover roads and bridge surfaces. Mayflies are totally harmless but some people are allergic to large quantities of mayfly bits.�� See pictures at  and radar at  (and what an amazing shot of a mass of newly-emerged mayflies on the water’s surface!).

Nice , and .
For a .
The BugLady has no experience with this site and is not endorsing it, but she was tickled to find .

The Bug Lady

The post Mayfly Revisited appeared first on Field Station.

The BugLady loves common names. They tell an amazing amount of information about the way a plant/animal looks, acts, sounds, what it was used for, what it might resemble from the Old Country, folklore, etc, etc. What common names don’t do is tell you who the plant/animal is, scientifically. The Mayfly isn’t remotely related to a housefly. It’s in the order Ephemerata (houseflies and their cohorts are Diptera), and it truly is ephemeral. Plus, the giant hatches for which mayflies are famous are not restricted to the month of May.

Female mayflies lay 500 to 1,000 eggs each, dropping them into or placing them under the water’s surface. Immature mayflies (naiads) are aquatic, living under water, especially running water, for 6 weeks to 3 years, and going through 21 molts as a naiad. Mayfly naiads chew on plant material and fish chew on mayfly naiads. Many species are habitat specialists, and pollution is threatening their survival.

When it’s time to emerge as adults, they have an unusual middle step. The nymph molts into a smoky-winged, transitional adult phase called a “sub-imago” (or “dun”) for a few hours, and then molts again into the final, clear-winged adult stage called the “imago;” (“spinner,” to fisherpeople). No other insects molt after reaching the winged, adult stage.

Mayflies emerge from the water by the googol, impairing visibility for drivers and causing the snowplows to be mobilized in some lakeside communities to clear their slippery little bodies off the roads. The BugLady calls this the “Normandy Beach” reproductive strategy—if you put enough soldiers out there, some will reach the beachhead (e.g. live long enough to mate).

They are eaten by birds, bats, dragonflies, toads, frogs and fish. Adults do not have functional mouth parts and do not eat; they only live for a few hours (ephemeral, get it?)

 
The BugLady

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