Bug o’the Week – Cuckoo Leafcutter Bee

Bug o’the Week

Cuckoo Leafcutter Bee

Greetings, BugFans,

The story of the Cuckoo leafcutter bee has several moving parts.  It starts with the family Megachilidae (of recent BOTW fame https://uwm.edu/field-station/leafcutter-bees-pollinators-extraordinaire/), a large and diverse group of solitary bees that includes the leafcutter, mason, and resin bees, and others.  Leafcutter bees are famous for their modus operandi – they cut tidy circles from the edges of leaves https://bugguide.net/node/view/55892 or petals and use them to wrap their egg packets https://bugguide.net/node/view/1252173, line the walls of tunnels (typically pre-existing tunnels in wood), and make walls between egg chambers.  There are 630 species in the Megachilidae in North America, and 4,100 species worldwide.

Within the Megachilidae, the tribe Megachilini contains the genus Coelioxys – the Cuckoo leaf-cutter bees, aka the Sharp-tailed bees (Coelia means “belly” and “oxys” means “sharp”).  The Coelioxys aren’t the only bees that are “cuckoos,” a term that refers to bees that lay their eggs in another bee’s nest; Rusty Burlew, on the Honey Bee Suite website, tells us that 20% of all bee species are nest parasites (another source put it at 15%) and that this behavior occurs in most bee families (which means, he says, that there’s “a whole lot of poaching going on”).  

The host bees aren’t just babysitting.  Cuckoo bees are “kleptoparasites” (kleptoparasitism means “parasitism by theft”).  Their offspring take advantage of the work of the nest-building/host female, eating the food stores she has collected and killing their rightful owner.  There are 46 species in the genus Coelioxys, and each species targets different species of bees, mostly from within their own Megachilidae family.  

Because they no longer make nests for their young (one website suggests that they’ve been nest parasites for so long that they’ve forgotten how), they are minimally-hairy (oddly, they have hairs on their eyes), and they lack the dense, pollen-collecting hairs under the abdomen that many leaf-cutting bees sport https://bugguide.net/node/view/30569/bgimage.  For that reason, they’re not good pollinators.   

One website says that “Cuckoo leafcutter species appear very similar to the casual observer, and species identification is often best left to an expert,” and the BugLady plans to take that advice (for a change).  Females have pointy abdomens https://bugguide.net/node/view/1593995/bgimage, and males’ abdomens are toothed https://bugguide.net/node/view/2050487/bgimage.  Most of our northern species are basic black with white lines, sometimes with red in the legs, but some Southern species are fancier – https://bugguide.net/node/view/1616384/bgimagehttps://bugguide.net/node/view/2093977/bgimagehttps://bugguide.net/node/view/1409086/bgimage.  Most are less than a half-inch long.   

Female Cuckoo bees are bee-watchers; they visit flowers to sip nectar, but also to spy on potential hosts and follow them back to their tunnels.  When its owner leaves, looking for more pollen, the cuckoo bee enters the tunnel and uses the sharp tip of her abdomen (a modified stinger) to puncture the leafy walls of an egg chamber and to lay her eggs inside.  Her larva will use its sickle-shaped jaws to bisect the host egg or larva, and it will kill any of its own siblings in the chamber.  It pupates in the egg chamber, and its emergence the following year will be synched with the flight period of its host.

Fun Facts about Cuckoo Leafcutter bees:

  • The genus name is pronounced “seal-ee-OX-ees.”

FOR THE RECORD: to every author out there who likened the actions of cuckoo bees to cuckoo birds (family Cuculidae), a clarification.  New World species of cuckoos (except for three species in South America) build their own nests and care for their own young; some (but not all) Old World members of the cuckoo family (the 56 members of the subfamily Cuculinae, the Parasitic cuckoos) are, famously, brood parasites.  The difference between a nest parasite and a brood parasite is that brood parasites, like our Brown-headed Cowbird, leave their eggs in other birds’ nests with the expectation that the adoptive parents will raise their young.  This often comes at the expense of the nest-maker’s brood, since the cowbirds hatch first, grow fast, monopolize the feedings, and may elbow the other chicks out of the nest. 

Kate Redmond, The BugLady

Bug of the Week archives:

BREAKING NEWS: in another fit of Political Correctness, the Entomological Society of America has renamed the Asian giant hornet, aka the Murder hornet, (a hornet that is, indeed, from Asia) “in an effort to reduce negative and nationalistic associations.”  It’s now the Northern Giant Hornet.  The BugLady supposes that the Asian multicolored ladybug will be next, but as BugFan Mike suggests, maybe the Negro bug https://bugguide.net/node/view/5184, nominally in the Ebony bug family, should come first.  

Bug o’the Week – the Dragonflies

Bug o’the Week

Cuckoo Leafcutter Bee

Greetings, BugFans,

The story of the Cuckoo leafcutter bee has several moving parts.  It starts with the family Megachilidae (of recent BOTW fame https://uwm.edu/field-station/leafcutter-bees-pollinators-extraordinaire/), a large and diverse group of solitary bees that includes the leafcutter, mason, and resin bees, and others.  Leafcutter bees are famous for their modus operandi – they cut tidy circles from the edges of leaves https://bugguide.net/node/view/55892 or petals and use them to wrap their egg packets https://bugguide.net/node/view/1252173, line the walls of tunnels (typically pre-existing tunnels in wood), and make walls between egg chambers.  There are 630 species in the Megachilidae in North America, and 4,100 species worldwide.

EASTERN PONDHAWK WITH MITES: When the BugLady first saw this dragonfly, she thought that for some reason his abdomen had gotten muddy, but a peek through the camera lens revealed that he was carrying a huge load of water mites.  Adult water mites are (mostly) free swimming carnivores, but they go through a tick-like nymphal stage in which they attach to and feed on other aquatic invertebrates (see their story at https://uwm.edu/field-station/water-mite-redux/). 

EXUVIA ON POTAMOGETON: The leaves and flower stalks of aquatic plants in the genus Potamogeton are dragon and damselfly magnets.  Here, a female Violet/Variable Dancer damselfly stands on a leaf as she oviposits in an underwater stem.  The empty damselfly skins (exuvia) that decorate the flower stalk show that it has been a busy place.   

EASTERN FORKTAIL: A female Eastern Forktail damselfly oviposits directly into the flower stalk.  The stalk will sink, and when her eggs hatch, her young will swim out into the water.

COMMON WHITETAIL: A recently-emerged female Common Whitetail dragonfly crawled out of the water, climbed 15” up the river bank, and then trekked another two feet across mown grass to find the perfect spot to stop and gather strength for her life in the air.  Dragonflies may take a few days to achieve their mature coloration – here’s what she’ll look like when the spots on her wings intensify https://bugguide.net/node/view/7160, and here’s the male https://bugguide.net/node/view/27710

RACKET-TAILED EMERALD: These very inquisitive dragonflies fly back and forth above the trail as you walk along.  When the sun is at your back, the glowing eyes of an approaching emerald are a religious experience! 

Slender Bluet
Marsh Bluet

SLENDER BLUET DAMSELFLY:  Bluets can be a confusing bunch of damselflies.  Some species are very distinct – one is neon blue at one end and yellow at the other, one is rainbow-colored, one is orange, and a few Eastern species are red.  But for many of the blue and black species, scrutinizing the male’s rear appendages is the best way to identify them (the Marsh Bluet terminates in a tiny pipe wrench).  You can narrow the field by eyeballing the comparative amounts of blue and black on the abdomen and putting them into the “blue-type,” “black-type,” or “intermediate-type” category.  This young male, who is in what BugFan Bob calls “that embarrassing purple stage,” will be a spectacular black-type bluet when he matures https://bugguide.net/node/view/1613844/bgimage.  And one of these days, the Slender Bluet will get a BOTW of its own.

DOT TAILED WHITEFACE: Not long out of the water, this Dot-tailed Whiteface clings to its shed skin (which clings to an Equisetum stalk) as it pumps up its wings.

DRAGONFLY DOW (dead on the water): Whether it was chased by a predator or just miscalculated, this dragonfly got too close to the water and adhered to its sticky surface film.  Beautiful even in death, its body is returning nutrients to the pond that nurtured it.

COMMON GREEN DARNER: Common Green Darners, one of our biggest dragonflies, are with us from May through September.  Wisconsin has two populations – migratory and resident.  Migratory darners like these, photographed in early May, arrive from the southeastern part of the US, mate, and put their eggs into the water, and their naiads develop during the summer.  About the time these early birds are wearing out (mid-June), the resident population begins to emerge, and they fill the skies until the end of summer.  The migrants emerge as adults at the end of August, and fly south, leaving no eggs in the ponds, but the eggs of the resident population overwinter under the ice.  A dragonfly do-si-do.

AMERICAN RUBYSPOT: Dragonflies and damselflies are fascinating, and they do some amazing things.  They can be a challenge to photograph and to identify, and some are just plain beautiful! 

RIVER JEWELWING: River Jewelwings are much less common where the BugLady lives than are the spectacular Ebony Jewelwings (https://bugguide.net/node/view/1840629/bgimage), so she was thrilled to get a picture of one.  Jewelwings and Rubyspots are members of the Broad-winged damselfly family Calopterygidae (which means “beautiful wing”), and they’re sometimes called river damsels because of their preferred haunts. 

SKIMMING BLUETS: The BugLady aimed her camera at an odd-looking configuration on a water lily leaf and saw one-and-a-half damselflies.  Apparently, a male and female were flying in tandem when a hungry bird came along and bit off the female’s abdomen.  When the pair landed, two Mesovelid bugs (aggressive scavengers and predators), sensed “blood in the water” and zipped in to sip her bodily fluids (hemolymph).  Just when you thought it was safe to go back in the water….

Go outside – look for dragonflies!

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Striped Fishing Spider

Bug o’the Week

Striped Fishing Spider

When the BugLady was on Riveredge’s excellent floating pier in the Milwaukee River last spring, she looked over and saw two, spectacular Striped fishing spiders on rocks above the waterline.

Fishing spiders are in the Nursery web spider family Pisauridae and in the genus Dolomedes, (the fishing spiders), so called because even though most of their diet is made up of aquatic invertebrates, these large spiders are hefty enough to catch tadpoles and small fish (as one website said, “They’re big enough to saddle up and ride”).  Because they’re found near water, they’re often called “dock spiders.”

They are marvelously adapted to locomote across – and under – the water.  These are pretty hairy spiders, and their “hydrophobic” (water-repellant) hairs allow them to dive under the surface film (to pursue or to escape) and to swim without really getting wet, and the air bubbles trapped in those hairs provide them with enough oxygen to stay under for about 30 minutes.  They can not only stand https://bugguide.net/node/view/311363/bgimage, “row,” and run across the water, they can glide across its surface using their raised front legs as a sail.    

Different spider families have unique eye arrangements – here are the eight eyes of a typical nursery web spider https://bugguide.net/node/view/1151143/bgimage.  Weber, in Spiders of the North Woods, says that their eyes glow green at night in the light of a flashlight. 

They catch their prey by ambushing and/or chasing it, not by making trap webs, but they do produce silk.  Fishing spiders spin silken lines to keep from being carried downstream, and females lay a trail of pheromone laced web across the water’s surface for males to follow.  They use silk to construct egg sacs, which they carry in their jaws, and later suspend it in a nursery web (wolf spiders also carry an egg sac around, too, but at the rear, attached to their spinnerets).  And, of course, newly-emerged spiderlings disperse by parachuting away from their siblings https://uwm.edu/field-station/spider-flight-rerun/.   

STRIPED FISHING SPIDERS (Dolomedes scriptus) (scriptus means “written”) are also called Writing fishing spiders because the markings on their abdomen look like a broad letter ”W” https://bugguide.net/node/view/122617/bgimage.  They are found around wetlands in southern Canada, much of the eastern US, and a few Great Plains states, and they prefer fast-flowing streams and rivers. 

Some have a white stripe around the sides of their cephalothorax and abdomen, and some don’t https://bugguide.net/node/view/1219135/bgimage.  There are several other species of large fishing spiders in the area that Striped fishing spiders can be mistaken for and, as always, BugFan Mike reminds us that the most accurate way to ID spiders is by aiming a hand lens at its naughty-bits (he may have used more technical terminology).  Males are smaller and have a slimmer abdomen than females https://bugguide.net/node/view/1225089/bgimage.  The books say that this species grows to a 2 ½” leg-span, but the BugLady is pretty sure that the two females she saw exceeded that.  

Their normal prey is mostly insects that they find on or in the water.  Striped fishing spiders typically sit on the shore or on floating leaves with their three front pairs of legs extended onto the water.  They can sense the ripples caused by insects that are swimming on the surface film (like water striders), or are trapped on it (like moths that dipped too close), or are swimming below it, and they rush out to apprehend them.  They also eat dragonflies, various fly and mosquito larvae that come to the surface to breathe, and other fishing spiders.  The BugLady found an article about a Striped fishing spider that was seen eating a small crayfish.  By the time it was discovered, the spider had anchored the crayfish with silk and had eaten most of its abdomen.  Researchers speculated that the spider had grabbed the crayfish from behind, avoiding its pincers as it injected its cocktail of toxins (their bites are not a problem for people unless you happen to be sensitive to them).  

Great predators though they are, they are also prey.  Striped fishing spiders are eaten by fish, frogs, birds, and even large dragonfly naiads.  And there’s a spider wasp (wasp family Pompilidae) that specializes in the Dolomedes spiders!  Anoplius depressipes https://bugguide.net/node/view/84121/bgimage, which at first glance resembles some solitary wasps in the family Sphecidae, collects fishing spiders and caches them in nest cells for her young to eat when they hatch.  Let the Missouri Department of Conservation “Discover Nature” Field Guide  tell it: “In the early 1900s, entomologists — including Missourian Phil Rau — noted an unusual sight: a wasp flying very low over a stream, dragging a spider across the surface film like a wind skier. It remained a mystery species among insect geeks until entomologist and nature writer Howard Ensign Evans identified it as Anoplius depressipes, one of the so-called blue-black spider wasps. It turns out this species hunts fishing spiders (Dolomedes spp.) and possesses specialized flattened front feet that are fringed with hairs, which allow it to walk on water, just like its prey. When transporting a spider, this species grasps the spider with its middle or hind legs, faces forward, then extends its forelegs and uses them like water skis while it propels itself and its prey across the top of the water, beating its wings, like an air boat in the Everglades https://bugguide.net/node/view/2039627/bgimage. This spider wasp sometimes dives down into water to chase its prey, since water spiders often swim underwater when frightened. Not surprisingly, it nests in burrows in stream banks.”

Curious thing – bugguide.net’s collection of pictures of any one species may contain three pictures or 300-plus.  There were only 13 shots of Anoplius depressipes, but seven of them had captured the wasp on water with prey https://bugguide.net/node/view/262134/bgimage!

Much has been written about female spiders dining on their inamoratos (it’s called sexual cannibalism); it’s not inevitable, but it does provide a nutritional boost for egg-making.  Male fishing spiders woo cautiously, and because she is already tuned in to the vibrations that insects make on the surface film, his signals must be different (his rhythm is slower than that of a trapped and frantic insect).  If she misreads his signals, or he misreads hers, or she’s just plain hungry, or if she gets the message, sizes him up, and he is found wanting, it doesn’t bode well for him. 

She may lay as many as 1,000 eggs, spinning a two-layered, waterproof sac around them.  She guards her offspring by carrying them with her jaws for a week or so until she senses that they’re hatching inside the sac https://bugguide.net/node/view/1572784/bgimage https://bugguide.net/node/view/277075/bgimage (she doesn’t eat for the duration – her mouth is already full).  She installs the sac in a three-dimensional jumble of silk in some leaves or twigs https://bugguide.net/node/view/1304813/bgimage and hangs around for another week or so https://bugguide.net/node/view/886889/bgimage to protect her spiderlings https://bugguide.net/node/view/886890/bgimagehttps://bugguide.net/node/view/1025906/bgimage.  The partially-grown spiderlings will overwinter in a sheltered spot.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Striped Hairstreak Butterfly

Howdy, BugFans,

Hairstreaks are spiffy little butterflies that are named for the hair-like markings found on their underwings.  Most have thin, twin tails (sometimes two pairs of tails) on the trailing edge of their hindwings, with bright blue/blue and orange eyespots nearby. Says Clarence Weed, writing about hairstreaks in Butterflies Worth Knowing (1922), “the slender tails, together with the enlargement of wings in back of them give the impression of a false head.  Along with this unusual development of the wing is to be considered the fact that these butterflies nearly always alight head downward so that the false head, furnished with what looks like waving antennae, takes the place that would naturally be occupied by the true head.”  Can you see a “face” here https://bugguide.net/node/view/1727485/bgimage?  Sometimes you see hairstreaks with a chunk of hindwing missing due to a predator thinking it was grabbing the tasty end of the butterfly and getting a less vital part instead.

They’re in the family Lycaenidae, which also includes the Blues/Azures, Coppers, and Harvesters, and they’re in the hairstreak subfamily Theclinae.  These are not big, charismatic butterflies – Wisconsin species tend to be on the quietly-elegant side – but there are brightly-colored species in and near the tropics.  Here’s a brief tour of some hairstreak species: https://bugguide.net/node/view/1753150https://bugguide.net/node/view/1856226/bgpage,


The more commonly seen Wisconsin hairstreaks are those that frequent bright flowers (especially butterfly weed) on sunny landscapes, and it’s not uncommon to find several species on one plant.  But some of our species, including the Striped Hairstreak, are also found in the shade.

Look for Striped Hairstreaks (Satyrium liparops) around woody and swampy openings and edges and in grasslands from the Rockies to the Atlantic (including southern Canada).  There are more of them the farther east you get.  Although they are found over more than half of the continent, they’re never common within that range.  “Scattered lightly over the landscape,” say the folks at the excellent Butterflies of Massachusetts website, “widely distributed although nowhere abundant.”  They speculate that Striped Hairstreaks may have benefitted, at least initially, from the clearing of Eastern forests for agriculture in the 1600’s.

These are small butterflies – 1” to 1 ½” – with a long and a short set of tails, and brown upper wings https://bugguide.net/node/view/239864/bgimage (pictures of hairstreaks with their wings spread are hard to get), and their underwings have a scattering of wide, slightly darker bands that are bordered by parenthesis-like white stripes.  The Edwards and the Hickory Hairstreaks have similar markings, so check your field guide.

They’re out and about in mid-summer.  Males scan the landscape for females from perches in the vegetation, and if they see a rival, will battle by flying around each other in an upward spiral.

[Quick aside.  When the BugLady was in grad school, her minor, briefly, was Ethology – Animal Behavior.  In one lecture, the professor was describing bloodless standoffs between two male fish that puff up and flare their fins at each other.  And the BugLady wondered – if you’ve never seen yourself in the mirror, and you (presumably) don’t have a sense of self-awareness, how do you know if your rival is bigger/tougher than you are, and you’d better back off?  Is life one big game of chicken?]

Anyway, females lay eggs, one by one, on the twigs of the caterpillar host trees, which include some species in the rose family like apple, hawthorn, Juneberry, and cherry, plus some species in the heath family (blueberry) plus a few others.  The eggs overwinter, and when they hatch the next spring, the caterpillars https://bugguide.net/node/view/656623/bgimage selectively eat the buds and flowers first (they are anthophagous), and then the tender leaves and fruit.  That sounds dire, but there are too few of them to cause real damage, and there’s only one brood per year.

Adults feed on nectar from wildflowers and from the flowers of shrubs like staghorn sumac, viburnum, and meadowsweet, and from chinquapin oak.  Butterflies of the Great Lakes Region tells us that “Early in the morning, they [adults] will sip dew from leaves as they bask,” and also that “The males perch low to the ground and are more sedentary and less interactive than the males of many hairstreak species. Adults spend a good deal of time walking on foliage and other perches rather than flying from place to place.  On cool mornings, basking males may find curled leaves at the tops of small bushes…and lie nearly flat against the interior leaf surface with closed wings held nearly perpendicular to the sunlight.  Here they absorb the maximal amount of solar radiation as well as energy from the leaf surface by radiation and conduction.  This allows them to warm up quickly and defend their territory from other males…”

Kate Redmond, The BugLady


BugFan Molly shared this link with the BugLady recently https://www.thecaterpillarlab.org/.  The BugLady knows nothing about it, and she is not on its board of directors.  But – great pictures, and check out the store!

Bug of the Week archives:

Bug o’the Week – Southern Spreadwing Damselfly

Howdy BugFans,

Full disclosure: the BugLady’s copy of Bob Dubois’s Damselflies of the North Woods (aka The Bible) automatically falls open to the page that shows the rear ends of the male Spreadwings.


So – what’s a Spreadwing damselfly? The order Odonata has two sub-orders – Anisoptera (dragonflies) and Zygoptera (damselflies).  Damselflies are further divided into the Broad-winged damsels (jewelwings and rubyspots), the Narrow-winged damsels (bluets, dancers, forktails, sprites, and more), the Spreadwings (family Lestidae), and a few other small groups.  “Spreadwing” describes how they perch – with their wings positioned in a backward-trailing “V.”  Usually.  Unless it’s cold and rainy or it’s a teneral (newly-emerged).


Spreadwings are large for damselflies (1.5” to 2”) and are not particularly brightly-colored.  Males have intense blue eyes and females’ eyes are pale blue or brown.  Sources agree that both male and female spreadwings can be tricky to ID – definitive identification requires examination of the damselfly’s nether regions with a microscope or hand lens, and in the field, females are best known by the company they keep.  Male Southern Spreadwings (https://bugguide.net/node/view/43409/bgimage) look a lot like male Northern Spreadwings https://bugguide.net/node/view/820173/bgimage, which look a lot like male Sweetflag Spreadwings (https://bugguide.net/node/view/477197/bgpage).  Photographers, alas, want labels for our pictures, and we sometimes take leaps of faith.

They aren’t strong flyers, and when they perch, it’s often at about a 45 degree angle, not quite as close to the ground as the sprites and bluets often perch.  They’re found near still waters with lots of vegetation, preferably with no predatory fish – the ideal habitats for their aquatic offspring.  A few live in streams or rivers with a very slow current, and some species are adapted for life in an ephemeral or temporary pond.

Male spreadwings hang out in the vegetation along the shoreline, but females stay away from the water until they are ready to reproduce.  Females lay eggs in plant stems above the waterline, sometimes alone https://bugguide.net/node/view/36973/bgimage, but generally in tandem with a male https://bugguide.net/node/view/1555986/bgimage (he’s guarding his genetic investment).  A few spreadwing species follow the general Odonate formula of hatching quickly, feeding, and then spending the winter underwater as a small, partly-grown naiad (immature).  Other species of spreadwings, the Southern Spreadwing among them, overwinter as eggs and push the restart button in spring.

Bob DuBois, in Damselflies of the North Woods describes their egg-laying practices this way, “This egg-wintering strategy allows them to utilize temporary ponds and vernal ponds that dry up during the summer or fall, because the eggs do not need to be wet all the time….The eggs immediately take some of the initial developing steps, but before hatching occurs they slip into a state of embryonic diapause (rest).  In this state, the drying-resistant eggs spend the winter inside plant stems where they withstand temperatures as cold as it gets in our region ….… after the snows melt and water levels rise in the spring, the dead plant is wetted, providing the moisture needed along with the right increasing temperatures and day-length cues to complete the hatching process. ….. The nymph stage is short for these egg-diapausing species – just two or three months in spring and early summer – because the fast-growing nymphs need to complete their development of about ten instars and emerge before the temporary ponds they live in dry up.

The biography of SOUTHERN SPREADWINGS (Lestes australis) is similar to that of other spreadwings.  Adults are found on the shorelines of quiet, weedy ponds and marshes.  They’re the earliest Lestes species on the landscape, and they have a very short flight period, appearing in May and fading before the end of June.  Adults eat small insects that they snag in the air, and naiads feed on the tiny aquatic invertebrates that they swim around with.

One of the reasons that Southern Spreadwings are so hard to distinguish from Northern Spreadwings is that they both used to be subspecies of the same species, the Common Spreadwing, and therein lies what Paul Harvey used to call “The rest of the story.”  Any birder can tell you of the joys of “lumping” and “splitting,” in which the Powers That Be split a species, creating another potential check-off for your life list, or lump two or three species, lowering your total (brace yourself birders – the Red Crossbills are about to explode).

Anyway, the Common Spreadwing was split.  Says Paulson of the Southern Spreadwing, in Dragonflies and Damselflies of the East, “With some structural differences and a somewhat different flight season, it probably deserves its rank as a full species, but genetic differences between the two are less than those between most species of spreadwings.”  To add to the confusion, Southern Spreadwings, whose historical range as a subspecies is south of Wisconsin, are moving north.

Scientists and citizen scientists are scrambling to define the edges of the range of the two species.  It may be impossible to know which of the early/pre-split Common Spreadwing records were the (now) Northern or the (now) Southern species, especially where the ranges of the subspecies overlapped.  Bugguide.net plots its range maps based on photos submitted by its members, and although they’re here, Wisconsin is not included on the Southern Spreadwing’s map yet.

Do Southern Spreadwings have resident populations here in Wisconsin or do they just migrate here?  DuBois says “It is not known if this species breeds successfully in our region, or if adults seen here move up from the south.”  They’ve been recorded in 13 Wisconsin counties https://wiatri.net/inventory/odonata/speciesaccounts/SpeciesDetail.cfm?TaxaID=168, and we know there is breeding activity, but are our winters too cold, for too long, to allow the egg in the stem in the open to make it to spring?

Finally, and at the risk of causing Lestes Overload – also moving into our neighborhoods is the Great Spreadwing (Archilestes grandis), a large (up to 2.4”) species native to the west and south whose range now extends to Massachusetts and Ontario (and includes Wisconsin https://wiatri.net/inventory/odonata/speciesaccounts/SpeciesDetail.cfm?TaxaID=126.  The range expansion may be due to climate change, or it may be explained by a proliferation of ditches and farm ponds (the naiad is tolerant of pollution) that allowed the species to hop-scotch across the continent.  Keep your eyes peeled.

The BugLady recommends this lovely offering from Chicago’s Field Museum of Natural History: https://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/388_0.pdf

Also – many thanks to BugFan Freda, whose pictures of the Southern Spreadwing are far better than the BugLady’s.

Think damselflies.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Agreeable Tiger Moth

Greetings, BugFans,

Years ago, the BugLady photographed a Giant Leopard moth https://bugguide.net/node/view/1967163/bgimage.  It was a tough shot – the moth was tucked up under the eaves of a house.  It’s – OK — but she wants another shot at it, and she also wants to photograph its very classy caterpillar https://bugguide.net/node/view/1746675/bgimage.  She fantasizes that when she does find one, the pictures will turn out better than her first attempt (one last amazing Leopard moth picture https://bugguide.net/node/view/924700.

Anyway, when she saw this Agreeable tiger moth caterpillar, she thought maybe it was a Giant Leopard moth, but it lacked the Giant Leopard moth’s scarlet bands around the segments (intersegmental rings).

Agreeable tiger moths (Spilosoma congrua), aka Yellow-legged tiger moths, are in the family Erebidae and the tiger moth tribe Arctini (from a Greek word meaning “bear,” a reference to their woolly caterpillars).  Adults are white, with a few black spots, and with a wingspread of about one-and-one-third inches https://bugguide.net/node/view/1930658/bgimage https://bugguide.net/node/view/1082541/bgimage, and they have pretty cute faces https://bugguide.net/node/view/632611/bgimage. There are a number of related tiger moth species whose adults are white and somewhat spotty, and they can be hard to distinguish http://daytoninsects.com/white-tiger.html.

The caterpillars come in two color morphs – black with yellow/orange intersegmental rings https://bugguide.net/node/view/322343/bgimage, and (like the Giant Leopard moth) black with red decorations https://bugguide.net/node/view/889559/bgimage.  Tiger moth caterpillars are bristly (woolly bears are tiger moths, too), and in some species, the hairs cause skin irritation.  The Agreeable tiger moth’s bristles are, well, agreeable.

They’re mostly found east of the Great Plains in woodlands, grasslands, gardens, etc.  Usually, animals that occupy a huge range are generalist feeders, and the tiger moths certainly are.  Agreeable tiger moth caterpillars eat a variety of herbaceous plants including dandelion and plantain, which are everywhere, and pigweed (Amaranthus sp.), and they also nibble on mushrooms https://bugguide.net/node/view/259755/bgimage.  The BugLady found a paper in which the authors speculated that an Agreeable tiger moth caterpillar that was seen feeding on a bracket fungus was probably eating the algae that grew on the fungus too, but fungi and algae appear to be only a tiny part of the species’ diet.

Some of their food plants contain toxins, chemicals that plants produce in order to discourage grazing (with varying degrees of success).  Insects that eat toxic plants either develop ways to rid their bodies of the poisons quickly, or they develop a way to sequester them in their body.  Agreeable tiger moths sequester chemicals called iridoid glycosides, which make them bitter and distasteful (but probably not lethal) to potential predators.  Sometimes, these chemicals are used in reproduction.

Adults fly from late spring through mid-summer here in God’s Country, and even longer in the South.  Some tiger moths (like the Woolly bear) overwinter as caterpillars, but the Spilosomas spend the winter in a pupal case https://bugguide.net/node/view/335864/bgimage inside a cocoon they construct using some of their own hairs https://bugguide.net/node/view/889561/bgimage.  Here’s a good series of pictures of the whole life cycle https://bugguide.net/node/view/311410/bgimage.

In her research, The BugLady came across an article that (irresistibly) began “This past weekend I attended the third annual “Caterwauling for Caterpillars” night” – a night that included a sighting of an Agreeable tiger moth caterpillar along with some other awesome caterpillars.  Here’s the blog: https://kylefromohio.blogspot.com/2017/09/caterpillar-extravaganza.html.

Bizarre Tiger Moth Fact: The hairs of a species in India are so irritating that they can lead to a serious skin and systemic condition called Lepidopterism when the population of a local tiger moth booms.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Carpenter Ants

Howdy, BugFans,

The BugLady lives in a log cottage that’s rough cedar on the inside (think splinters), so when, one night, this Carpenter ant queen dropped down from the ceiling onto a book she was reading, she may have overreacted a tiny bit, and the ant met with an unfortunate accident.  Here’s a healthier individual https://bugguide.net/node/view/787312/bgimage. (Thanks to honorary BugFan PJ for confirming the ID)

Disclaimer: the BugLady doesn’t give advice on insect control or eradication.  That being said, if you see carpenter ants in your house, or if you hear the faint, rustling sound of chewing (it’s been likened to cellophane crinkling), get help.

Carpenter ants (called “sugar ants” in Australia) are in the ant family Formicidae and the genus Camponotus (which means “flat back”).  There are about 1,000 species in the genus worldwide – 50 in North America – and since the BugLady doesn’t know which species she had, the term “carpenter ant” here is generic.  They’re usually found where there are trees, but some nest in soil and others enjoy grasslands and even deserts.  They’re active all year round in warmer climates, but here in God’s Country, they enter a state of suspended development called diapause in the winter (unless they’re in the walls of a heated dwelling).

These tend to be large ants, and depending on species, they come in black, yellow, red, or brown, as well as two-toned.  They’re called polymorphic (“multiple-forms”) because there are three sizes of workers https://bugguide.net/node/view/729102/bgimage – minors, medias, and majors – plus large queens and half-sized males.

Like other communal insects, carpenter ants have a complex social system.  A queen mates with as many males as possible during her nuptial flight and uses that stored sperm for the rest of her life, which can be as long as 15 years.  She seals herself into a small cavity in wood or under bark and lays about 20 eggs.  When they hatch, she nourishes the larvae herself, using her fat reserves and protein from her wing muscles, and when they emerge from their pupal cases as adults, these new workers break out of the chamber and take over the nest duties https://bugguide.net/node/view/636620/bgimage.  The larger workers are guards and foragers; the smaller ones excavate and tend to the nest and care for the queen and the nursery (they feed their charges by regurgitating food – trophallaxis).

She lays eggs twice a year.  Some of the early spring eggs, specially nurtured, will become winged, fertile, royal ants (swarmers), and the rest are workers.  The late summer eggs produce workers that emerge the next year.  A nest usually doesn’t produce its first swarm until it’s three or four years old and contains several thousand ants.  A thriving carpenter ant colony often includes a parent nest and one or more satellite nests.  The parent nest is humid, excavated in damp wood, and the ant eggs need this high humidity.  Once the eggs hatch, the workers tote the larvae to satellite nests where the humidity is lower.

What fuels carpenter ants?  They’re omnivores and scavengers and sometimes predators, but the wood they chew is not a part of their diet (unlike termites, they don’t have the proper gut flora to digest cellulose).  Workers mostly eat carbs – sap, fruit, the liquid from extrafloral nectaries (https://uwm.edu/field-station/ants-in-my-plants/), (and discarded candy https://bugguide.net/node/view/1911307/bgimage), and they farm aphids, scales, and treehoppers https://bugguide.net/node/view/1537739/bgimage for the sweet honeydew these insects excrete.

The developing larvae require protein, which workers collect in the form of dead (and sometimes live) insects https://bugguide.net/node/view/957396/bgimage.  When they find one, a group may gather and carry it back to the nest, or they may eat it on the spot, carrying the nutrients back in their crops, and leaving the shell behind.  They usually forage at night.

When they have a long-term food source (like a herd of aphids) carpenter ants lay a pheromone trail for their sisters to follow, and they may use underground tunnels to get to their food source, too.  They can go without food for six months, but they may respond to a food shortage with a little cannibalism.

Who eats carpenter ants?  People do, for one.  The adults and larvae are eaten around the world, and Wikipedia tells us that in the early days of this country, lumberjacks in Maine ate carpenter ants to prevent scurvy.  We share them with wildlife like bears, skunks, big brown bats, salamanders, songbirds, wild turkeys, and, famously, Pileated Woodpeckers.

Carpentry is their raison d’etre, and in their proper place, they are important decomposers (a study in the Northeast determined that 75% of carpenter ants are found in dead trees).  They tunnel in wood that’s been softened up a bit by moisture (an important thing to remember if you’re trying to avoid carpenter ants in your walls), and their tunnels open up a decaying tree to more moisture and to fungi.  They tear the soft wood with their sturdy jaws https://bugguide.net/node/view/1615668/bgimage forming long tunnels called galleries https://bugguide.net/node/view/1783110/bgimage.

The tunnels are clean and are sometimes described as looking “sanded.”  Wood shavings that result from their excavating, along with desiccated bits of food, and deceased ants are removed from the tunnels – dumped out of a hole in the trunk that’s sometimes called a “window.”

Fun Carpenter Ant Fact: when the workers are alarmed, they may warn their sisters by whacking their mandibles and abdomen against the inside of the tunnel walls, making a loud sound that is sometimes audible even to us.

Another Fun Carpenter Ant Fact: they are gentle souls that would rather live to fight another day, but if they are mishandled, they will bite (painfully) and then squirt a little formic acid into the bite for good measure.  They don’t sting.

BugFan Bill invites BugFans who would like to dive a deeper into the world of insects and insect issues to check out the Conservation and Ecology – Insects in the Midwest Facebook group https://www.facebook.com/groups/183261300269413.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Bugs in the News XI

Howdy, BugFans,

Hawks are still flying; bugs, not so much.  Lots of grasshoppers along the trail, and a variety of flies and some sweat bees on the late-blooming dandelions (and just two weeks ago the BugLady was photographing late dragonflies).  It’s definitely feeling like November on the hawk tower.  The BugLady’s trusty 50-year-old hand anemometer measured a 49 mph gust the other day.

Here are some interesting articles and beautiful pictures from the BugLady’s overflowing media folder.

Learn about the 14 WAYS SPIDERS USE SILK – https://www.smithsonianmag.com/science-nature/fourteen-ways-spiders-use-their-silk-180978354/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20211027-daily-responsive&spMailingID=45847821&spUserID=ODg4Mzc3MzY0MTUyS0&spJobID=2102995663&spReportId=MjEwMjk5NTY2MwS2

BUMBLEBEE VOMIT – A former Governor of Wisconsin famously referred to honey as “bee poop” (guess what our state insect is?).  Speaking of bodily functions, here’s an article about bumblebee vomit – click on the link in the short, italicized paragraph (“Want to learn more about the science behind bumblebee vomit?  Click here to see some of the resources we used to help write this episode!”):   https://www.npr.org/2020/03/13/815715527/the-buzz-on-bee-barf-sticky-science-behind-bumblebee-vomit?utm_source=npr_newsletter&utm_medium=email&utm_content=20200317&utm_term=4464619&utm_campaign=news&utm_id=2548916&orgid=675

And – while we’re at it, HONEY is remarkably good for bees: https://www.smithsonianmag.com/science/honey-has-health-benefits-for-bees-180978917/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20211025-daily-responsive&spMailingID=45834577&spUserID=ODg4Mzc3MzY0MTUyS0&spJobID=2102700229&spReportId=MjEwMjcwMDIyOQS2

AWESOME MOTH SHOTS — https://aeon.co/videos/witness-the-majesty-of-moths-taking-flight-at-6000-frames-per-second.  Thanks, BugFan Bill.

ICE WORMS fall within the BOTW mission (the BugLady thinks maybe she saw the movie…).  https://www.npr.org/2021/07/13/1011376403/its-summer-and-that-means-the-mysterious-return-of-glacier-ice-worms?utm_source=npr_newsletter&utm_medium=email&utm_content=20210713&utm_term=5565492&utm_campaign=news&utm_id=2548916&orgid=675&utm_att1=

SPECTACULAR MACRO PHOTOGRAPHY, although, alas, we can’t say “no insect was harmed to make this picture.”  https://www.npr.org/sections/pictureshow/2021/08/19/1025545652/military-photography-bugs-pablo-piedra?utm_source=npr_newsletter&utm_medium=email&utm_content=20210820&utm_term=5679937&utm_campaign=news&utm_id=2548916&orgid=675&utm_att1=

The SPOTTED LANTERNFLY is established in New York and Pennsylvania and has been seen in Ohio and southeastern Indiana.  Here’s more about the beautiful, invasive insect that will be a game-changer for the fruit-growing industry – https://www.smithsonianmag.com/smart-news/see-spotted-lanternfly-squash-it-officials-say-180978545/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20210830-daily-responsive&spMailingID=45541229&spUserID=ODg4Mzc3MzY0MTUyS0&spJobID=2067368472&spReportId=MjA2NzM2ODQ3MgS2.

MURDER HORNETS 2021 – the BugLady is blown away by pictures of people in moon suits, vacuuming up Murder hornets.  https://www.smithsonianmag.com/smart-news/entomologists-eradicated-first-asian-giant-murder-hornet-nest-2021-180978543/

DRAGONFLY WINGS – something unexpected to lay at the door of climate change – https://www.smithsonianmag.com/smart-news/warmer-climate-may-cause-male-dragonflies-lose-their-patchy-wings-180978141/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20210712-daily-responsive&spMailingID=45289685&spUserID=ODg4Mzc3MzY0MTUyS0&spJobID=2043035771&spReportId=MjA0MzAzNTc3MQS2

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Forked Fungus Beetle Redux

Howdy, BugFans,

The BugLady has been out counting migrating raptors.  Here’s a rerun of an episode about an amazing beetle that the BugLady encountered in the late spring of 2014.

Every once in a while, life hands you a special treat.  Late one recent afternoon, the BugLady was walking through the beech woods, moving far too slowly, considering the size of her mosquito escort, scanning a fallen log that was adorned with a few deteriorating shelf fungi (can you spell “bug-nerd?”).  Suddenly, part of a fungus twitched.

If you’re singing along, we’re on page 192 of your Kaufman Field Guide to Insects of North America or page 583 of the Audubon Society Field Guide to North American Insects and Spiders – the forked/horned fungus beetle (Bolitotherus cornutus) (“crowned”).  The Forked fungus beetle is in the Darkling beetle family Tenebrionidae and is the only species in its genus.  It’s found east of the Mississippi, at night, in the woods, in the company of woody, polypore shelf fungi.

Males look like half-inch long “triceratops.”  Their horns can vary in size quite a bit, and most males have a small, forked, rhino-like horn at the end of their snout https://bugguide.net/node/view/788389/bgimage that the BugLady does not see in her photographs (hers is a bi-ceratops).  Females don’t have horns, but the lower edges of their heads are widened, and they wear an extra bit of armor plate on their opposite ends (more about that later).  They are drab, knobbed, pitted, exceedingly “thick-skinned,” and primordial.  Oh, but then there’s that beautiful gold fringe on the underside of the male’s horns https://bugguide.net/node/view/1864012/bgimage – The Beetle with the Fringe on Top.  It has been suggested that the hairs serve some general sensory function, but the BugLady couldn’t find any corroboration of that, and considering the Forked fungus beetle’s lifestyle, the hairs must take quite a beating.

About the natural history of the Forked fungus beetle we know plenty, thanks to research done in the 1950’s by M. Pferrer Liles and in the ‘60’s by Ann Pace (http://www.americaninsects.net/b/forked-fungus-beetles.html).  All stages of the beetle live, overwinter, reproduce and feed in/on woody shelf fungi (here in God’s Country they like the “artist’s fungus,” Ganoderma applanatumhttps://bugguide.net/node/view/422117/bgimage.  Once they find a good fungus, a small population of beetles may occupy it for as long as nine years, moving on when the fungus is no longer usable.  Larvae https://bugguide.net/node/view/1519099/bgimage turn the fungus into a honeycomb of tunnels.  Though there may be several larvae in a tunnel, they stay out of each other’s way; but if, in its travels, a larva stumbles across a Forked fungus beetle pupa, it might cannibalize the pupa.  M. Pferrer Liles noted that larval tunnels often contained masses of white mycelium (fungal strands) that had grown around and permeated the body cavity of a dead Forked fungus beetle larva.  Fungus mummifies larva – sounds like something the BugLady saw on “The X-Files.”

They have few predators.  A braconid wasp parasitizes the larvae, and a few nocturnal mammals try to eat them (more about that later, too).

So, what was the twitching all about?  The male initiates courtship by climbing onto the female, facing the opposite direction and griping her elytra (hard wing covers).  Scientists have actually measured a Forked fungus beetle’s grip strength, because having won Fair Maid, he may be dislodged by the horns of her other ardent suitors.  Males use the horns in pushing contests, and the guy with the biggest horns usually wins; likewise, bigger beetles have longer legs and a stronger grip.  Anyhow, there he sits, rubbing her head with his feet and, yes, twitching.  In this position, the underneath of his abdomen rubs against two “tubercles” on the top of her thorax.  The friction may produce a rasping sound that can be heard six or more feet away (the BugLady didn’t hear it, but the sound is typically made at night, and the movements can be made without producing the sound).  Courtship may last several hours.

When copulation is imminent, he turns around so they are facing the same direction.  According to one source, females do not pick their suitors, but they can decide which male shares his bodily fluids with them.  If she is not receptive to the male, she can block the transfer of his spermatophore by not opening the heavy plates at her rear.  After mating, the male stays in place for a long time, guarding his investment from other males.

A female lays very few eggs a year (a dozen at most), and before each egg, she must court.  Eggs are laid singly, in the early evening, in cracks on the tops and sides of the fungus.  She picks her nursery carefully – studies have shown that larvae that develop in larger fungi not only have a better survival rate, but the male larvae will have larger horns when they mature (and they’ll get all the girls).  Once laid, each egg is plastered over with what was tactfully described as “a dark, excrement-like material” that is smoothed down by hairs on the female’s abdomen.  Here are some pictures of life stages https://bugguide.net/node/view/97208/bgimage.

Forked fungus beetles lead unhurried lives.  The larvae stay in their eggs for several days after hatching, eating the capsule itself before burrowing into the spore-bearing tissues of the fungus.  New adults stay in their pupal cases for a few days after emerging, until their color darkens (here’s a newly emerged male http://bugguide.net/node/view/97192/bgimage).  An adult may live for four or five years, never venturing far from its natal fungus.  In fact, until 1999 scientists were unsure about whether Forked fungus beetles could even fly (they can), and assumed that FFBs hoofed it across the forest floor to new sites.  There are two generations per year; larvae overwinter within their fungi; adults stay in fungi, decaying stumps, and under tree bark.

It’s hard to imagine that a beetle that looks as though it heaved itself up out of the very wood itself would need a sophisticated defense system, but the Forked fungus beetle has a dandy one.  Oh, sure, a startled adult Forked fungus beetle, like many other kinds of beetles including Tenebrionids, plays dead (death feigning).  It tucks its legs into dedicated grooves on the underside of its body, and blends in with its surroundings.  But, it’s got a chemical trick up its sleeve, too.

When it feels threatened, a Forked fungus beetle releases a nasty-smelling, irritating potion that causes a potential predator to reconsider.  Rather than squirting the liquid like a squeeze bottle, Forked fungus beetles carry the chemical deterrent in two “eversible” abdominal glands that turn inside out like a pocket.  What’s unique is the timing and the trigger.

In Secret Weapons, Eisner says that “An unusual feature of B. cornutus is that it may extrude its glands preemptively, in response to the mere anticipation of an attack.  All you need do to cause the beetle to evert its glands is to breathe on it.  This readiness to deploy its chemical weapons may serve the beetle well, especially in defense against predators such as mice, which could afflict a fatal injury with their very first bite.”  Eisner goes on to say that the Forked fungus beetle defines a “breath” as a warm, moist, pulsing puff of carbon dioxide.  Producing a chemical defense is costly, energy-wise, and the Forked fungus beetle is unusual in using it before its predator actually makes contact.  The unfortunate herbivore that mouths an inhabited fungus may suffer the same fate.  Forked fungus beetles do not use a cannon to kill a gnat – when nibbled by an ant, they depend on the toughness of their exoskeleton.  For many close-up pictures, including some of a beetle spraying, see http://www.performance-vision.com/FungusBeetle/.

Last but not least – yes – phoresy!  Those legged, pink dots on the female’s head are mites!  A number of different species of mites have been documented on Forked fungus beetles.  In one study, researchers checked Forked fungus beetles in a museum collection for phoretic (hitchhiking) mites and found them on about one-third of the beetles.  The mites are species that live in fungi – some eat spores – and they take advantage of the Forked fungus beetle’s longer legs to get around.

Those horns remind the BugLady of one of her favorite cartoon characters, The Tick.  And as the Tick once said, “Mysteries abound.”

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Therion Wasp

Greetings, BugFans,

The BugLady stood on a boardwalk in a wetland for about half an hour trying to photograph this amazing wasp as it dodged through thickets of sedges, ferns, and orchids, staying below knee-level, never landing.  This is the best picture she got.  She ID’d it as an ichneumon wasp in the genus Therion.

A quick review of Ichneumon wasps, since we haven’t been there for a while.  Ichneumonidae is a very large family indeed, with 25,000 known species worldwide (5,000 of them in North America) and as many as 75,000 additional species that may be waiting to be discovered!  They live everywhere they can find prey (except Antarctica), and there are so many species spread out over so many areas that the life stories of most are not known.

They range in length from 1/8th of an inch to 3 inches, and some are very colorful.  Many have long, slim abdomens that flare at the end, some tipped with impressive ovipositors https://bugguide.net/node/view/2001653/bgimagehttps://bugguide.net/node/view/1950499/bgimagehttps://bugguide.net/node/view/1828581/bgimage.  With a few exceptions, Ichneumons don’t sting, and you have to mess pretty seriously with those that do in order to get them to do it.  Their long antennae (often at least half as long as their body) have lots more segments than do those of other wasps, and many species have a white or yellow band midway along each https://bugguide.net/node/view/1924235/bgimage.  They’re tough to identify – the Field Guide to Insects of North America says that most of the photos submitted to be used in the book could not be identified, even by experts.

“Ichneumon” comes from a Latin word that was derived from an Ancient Greek word meaning “tracker,” so-named because of the way females hunt for other invertebrates.  The larvae of Ichneumons are parasitoids – sometimes on spiders, but mostly on insects that have complete metamorphosis (egg–larva-pupa–adult).

She lays her egg, often accompanied by a shot of venom, on or in her prey, usually the larva of a beetle, butterfly/moth, or another wasp; and many species of ichneumon target particular genera or groups of prey.  When it hatches, her larva starts feeding on the non-essential parts of its host, keeping it alive by leaving the vital organs for last.  Without ichneumons, the world would be overrun by caterpillars.

Adults feed on nectar, sap, and water (some species also eat pollen), and bugguide.net tells us that many adult ichneumons overwinter as adults under loose tree bark.

There’s a genus of Ichneumon wasps that is named Ichneumon, and the resulting confusion between genus and family has caused some Ichneumonid experts to refer to the family as Darwin wasps.  Darwin, along with his Victorian contemporaries, was so horrified by the parasitoid lifestyle that he famously said: “I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars.”

Most sources list 14 species in the genus Therion in North America (20 globally), and they can be difficult to tell apart, so the BugLady assumed her well-worn seat, way out on that taxonomic limb and guessed that this is Therion circumflexum (no common name).  She felt better about her guess when she found a 1973 paper by C. N. Slobodchikoff, in which he states that “It has recently been shown that all North American Therion can be considered as members of a single species Therion circumflexum,”and he refers to the rest of the named “species” as morphological types.  Apparently, it’s been re-thought since then.  There’s not a huge amount of information available about the species, but at least the contributors to bugguide.net have gotten better pictures of it than the BugLady did: https://bugguide.net/node/view/644490/bgpagehttps://bugguide.net/node/view/752769/bgimagehttps://bugguide.net/node/view/482314/bgimage.

Therion circumflexum (“circumflexum” is Latin for “bent about”) is in the subfamily Anomaloninae, and its posture in flight, with outstretched antennae and an elevated rear, is typical of the subfamily.  Weighing in at a little more than an inch long, it’s one of the larger members of the genus.  It’s found not only in North America but also in the UK, northern Europe, Asia, and even North Africa, and its habitat is listed as “oak-chaparral and willows.”

They often perch vertically, and they spend lots of time grooming – antennae first, then mouth, then legs and wings, and finally, abdomen.

After mating, females fly away, but males lie on the ground for a minute or two, abdomens curled up, wings and legs splayed, looking like dead wasps, before they, too, leave.  Females search for caterpillars during zig-zag flights and also on foot, in vegetation, using their antennae.  They target the larvae of moths and butterflies, and their diet is more catholic than that of many other ichneumons.  Females locate a potential host by smell, and then they sweep their antennae over its exterior, making sure that the caterpillar isn’t hairy or spiny and therefore difficult to deliver an egg into.  If it passes muster, she uses her short ovipositor to insert an egg.  The host larva may undergo its full (though weakened) development before the Therion larva delivers the coup de grace, and the ichneumon matures within the pupa of its dead host.

Nature red in tooth and claw.

Kate Redmond, The BugLady

Bug of the Week archives:

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