Category: Bug of the Week

Bug o’the Week – Mid-summer Stories

Bug o’the Week
by Kate Redmond

Mid-summer Stories

Howdy, BugFans,

It’s August!!!  Or, to put it another way, it’s August – yikes!  Halfway(ish) through summer.  Here are some of the sights that the BugLady has enjoyed so far.  Many of these have already starred in a BOTW of their very own – you can look them up in the UWM archives by Googling “UWM Field Station (name of insect).”

FOUR-LINED PLANT BUGS: Most Mirid plant bugs are small and green or beige or mottled, and therefore pretty inconspicuous.  Not so the Four-lined plant bug, which is as showy as a nymph https://www.bugguide.net/node/view/1670391/bgimage as it is as an adult.  These urban/suburban/grassland bugs feed on plants – wild, cultivated, and agricultural, especially the mints – by piercing the plant tissue and feeding on the sap.

TREEHOPPER EXUVIA: On a recent trip to Spruce Lake Bog the BugLady noticed a number of Buffalo treehoppers https://www.bugguide.net/node/view/2014389/bgimage, and then she found this shed skin (exuvia).  Buffalo treehoppers have improbable nymphs https://www.bugguide.net/node/view/1014470/bgimage that leave equally improbable skins behind when they shed.  Adult treehoppers communicate with each other and with their young by vibrating their abdomens against whatever surface they’re sitting on.

EASTERN AMBERWING:  Good things come in small packages!  At 0.90” long, the Eastern Amberwing is our second-smallest dragonfly, but one of our flashiest.

CLYTUS RURICOLA:  What a dynamite beetle!  It’s a long-horned beetle (family Cerambycidae) that is sometimes called the Round-necked long-horned beetle, and it’s disguised as a wasp (just when you thought it couldn’t get better, here are some relatives https://www.bugguide.net/node/view/128534/bgimage and https://www.bugguide.net/node/view/2361925/bgimage).  Look for the adults on flowers, eating pollen.  The larvae live concealed in rotting wood, especially maple.

moth blinded sphinx female
blinded sphinx moth female
moth blinded sphinx male
blinded sphinx moth male

BLINDED SPHINX:  Back in mid-June, the BugLady threaded her way down a narrow boardwalk with tall grasses on all sides hoping to find some damselflies.  On her way back, she saw a male Blinded Sphinx moth and an egg-laden female in a state of disarray.  She hadn’t noticed them on her first pass, when she apparently brushed against them as they were sharing a “Get-a-Room” moment.  She added insult to injury by shoving a camera in their faces before she tiptoed away. 

CRAB SPIDER:  The BugLady loves trying to spot mini-crab spiders lurking on flowers.  Goldenrod crab spiders (obviously not restricted to goldenrods) can change color from white to yellow to white again, though each change takes a few days. 

BLACK AND YELLOW MUD DAUBER:  A solitary, thread-waisted wasp.  Yes, she can sting, but you’d have to work at it (bees and wasps that defend large, communal nests/hives are the most dangerous).  The mud she collects will be fashioned into a globular nest containing (usually) 6 to 15 egg cells https://www.bugguide.net/node/view/888662/bgimage that she provisions with spiders for her eventual young (she sips nectar, but her larvae are carnivores).

SCORPIONFLY:  First of all, Scorpionflies are not true flies (order Diptera), they’re found in the Order Mecoptera, along with several groups of odd-looking insects like hangingflies https://www.bugguide.net/node/view/971801/bgpage, forcepflies https://www.bugguide.net/node/view/2031144/bgpage, and Snow scorpionflies https://www.bugguide.net/node/view/1651225/bgimage.  And they’re not scorpions, either, though males of one family (Panorpidae) have a bulbous, stinger-like, appendage at the tip of their abdomen https://www.bugguide.net/node/view/205845/bgimage (they don’t sting, either).  For more details about Scorpionflies, see https://uwm.edu/field-station/bug-of-the-week/scorpionfly-revisited/.  In the final paragraph of that account, the BugLady says that there are more than 80 episodes in the BOTW.  Now there are more than 800. 

WASP ON WATER:  Insects that fly too close to the water risk getting trapped on the surface film – the water molecules that are exposed to air at the surface are “stickier” than those below.  What happens next?  If it’s lucky, the wasp will bump into something to climb up onto.  Otherwise……..

WATER STRIDERS…..Otherwise, it will become prey for some predator, and these water striders are likely candidates (this is a pair, indulging in a bit of hanky-panky).  They were skimming along the surface just a few feet from the wasp but were otherwise occupied.  Water striders are sometimes called Water spiders (they’re not – we need to enunciate) or Jesus bugs (because they walk on water).  Water striders monitor the water’s surface with their two front legs as they locomote with their four hind legs, and they are attracted by the mini-ripples produced by an insect struggling on the surface.  

BLACK-SIDED MEADOW KATYDID – the BugLady loves finding infant katydids, although this one didn’t want to be found – it immediately ducked in back of the nearest plant stem.  The folks at bugguide.net did a better job https://www.bugguide.net/node/view/2547384/bgimage.   They grow up to be pretty spiffy https://www.listeningtoinsects.com/black-sided-meadow-katydid, and they sing (exceedingly softly) from perches at the edges of wetlands in late afternoon and at night.

ARROW CLUBTAIL DRAGONFLY:  It takes about 45 minutes to get to this stage after the dragonfly naiad has climbed out of the water and pushed its head out of its split skin.  Its wings need a little more length and strength before this teneral (newly-minted dragonfly) can launch itself straight up into a tree.  It takes a few days before a teneral gains it’s adult coloring and the duckling turns into a swan https://www.bugguide.net/node/view/17871/bgimage.   

WASP WITH SPIDER:  A small, life-or-death struggle had already been decided when the BugLady saw them.  It was “man bites dog” – a wasp (Episyron quinquenotatus)(probably) had collected a small orb-weaver, paralyzed it, and was dragging it to a tunnel where she would stuff it into a chamber, lay an egg, and close the chamber off.  When the egg hatches, the eventual larva will feed on the spider, pupate in its chamber, and emerge the following summer.  

PHANTOM CRANE FLY:  Someone asked the BugLady recently if she believes in magic.  The obvious answer – How can you be out in Nature and not believe in magic?  Example: Phantom crane flies, flickering along in dappled sunlight at the edges of wetlands.  As Dar Williams sings, “We find magic everywhere.”

Go outside – find some magic! 

Kate Redmond, The BugLady

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

Bug o’the Week – Dun Skipper Butterflies

Bug o’the Week
by Kate Redmond

Dun Skipper Butterflies

Greetings, BugFans,

Seasoned BugFans know that the BugLady’s relationship with skipper butterflies is fraught.  These are small, speedy butterflies, most of which are either orange and brown, or brown and orange. Her interactions with skippers always start with the question, “What is it?” and end with “Are you sure?”

She’s (usually) pretty sure about Dun Skippers (Euphyes vestris), family Hesperiidae (the Skippers) and subfamily Hesperiinae (the Grass Skippers, so-called because the caterpillars of most species feed on and shelter in the leaves of grasses and sedges).  They’re also known as the Dun Sedge Skipper and the Sedge Witch.  Witch?  They’re one of three skippers (the others are the Northern Broken-dash https://www.bugguide.net/node/view/2068070/bgimage, https://www.bugguide.net/node/view/2010950/bgimage and the Little Glassywing https://www.bugguide.net/node/view/2135356/bgimage, https://www.bugguide.net/node/view/1991796/bgimage whose flight periods overlap and who are called the Three Witches.  The “Minnesota Seasons” website quips that they are thus named “because their dark wings make it difficult to tell ‘which one is which.’”  They occur in North America in grasslands and along moist stream, wetland, and woodland edges east of the Great Plains.  

[Nota Bene: the BugLady regrets, whenever she sees a range map like this https://www.bugguide.net/node/view/18403/data, not buying, decades ago, a copy of a National Enquirer in the checkout lane that featured a story about how a giant earthquake was going to fracture the continent from north to south along the Mississippi River.  The accompanying map showed the Mississippi drawn along the western edge of Minnesota, Iowa, Missouri, etc.]  

But we digress. 

Dun Skippers are small (about 1” to 1 ½” wingspread), deep chocolate-brown skippers that sport a few pale spots on the upper surface of the forewing if they are females, and a diagonal black line if they are males. 

They like wetlands because the caterpillar host plants are sedges.  Various sources report that Dun Skippers feed on the sun sedge (Carex heliophila), tussock sedge (Carex stricta), and Chufa/Nut grass (Cyperus esculentus), but the estimable Butterflies of Massachusetts website states that “It is amazing and unfortunate that the exact host plant used by Dun Skipper in Massachusetts is not known,” and they speculate that because of their wide distribution, Dun Skippers probably also use some grass species.  Adults sip nectar from white, pink, and purple flowers, and males also absorb minerals and moisture from damp ground, carcasses, and animal droppings (feels like there’s a Joseph Conrad allusion in there somewhere).

dun skipper male
dun skipper female

Males scan for females from perches on vegetation during the first half of summer.  Eggs are laid in the middle of sedge leaves, and when the caterpillars hatch, they feed nocturnally on the leaves and make shelters by rolling or webbing them together into tubes.  They overwinter as caterpillars, resume feeding in spring https://www.bugguide.net/node/view/1038810/bgimage, and then pupate in a silk-lined shelter low on the host plant, emerging as adults in very late spring/early summer.  There’s one brood per year in our neck of the woods, but more in the South.

Dun Skippers have a wide range and are adaptable enough to use a variety of habitats, so they’re predicted to do well in a warming climate.

Kate Redmond, The BugLady

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

Bug o’the Week – And Now for Something a little Different XXI – Oaks and Hickories

Bug o’the Week
by Kate Redmond

And Now for Something a little Different XXI Oaks and Hickories

Greetings, BugFans,

Back into the wonderful world of plants, in this case, of trees that are super-important to insects, as well as to other wildlife – and to us.

Oaks are our national tree (who knew??!!), and because of their beauty, strength, longevity, and utility, they’re packed with cultural and religious symbolism in America and throughout Europe. There are 90 species of oaks in North America (about 500 worldwide), with nine oak species native to Wisconsin. They are second only to maples in Wisconsin’s woodlands, where oaks are called a “keystone species” – a species whose presence shapes the structure of its community. If a keystone species is removed, the community changes dramatically. Hickories grow with oaks in mixed, deciduous woodlands.

Oaks are in the Beech family, and shagbark hickory is in the Walnut family. Both have leaves, twigs, and branches that are arranged alternately; oak has simple leaves, and Shagbark hickory has large, compound leaves whose leaflets spread out like a fan. Oaks are divided into two groups that can be recognized by their leaves. Trees in the white oak group (in Wisconsin, the white, chinquapin, swamp white, and bur oaks) have leaves with rounded lobes and tips, and species in the red oak group (the black, northern red, pin, northern pin, and scarlet oaks) have pointed tips. 

shagbark hikory
shagbark hikory

Both oak and hickory are slow-growing, sun-loving, good-looking trees that make great yard trees.  Their tap roots grow down, rather than sideways through lawns, sidewalks and driveways. They tolerate weather extremes, thrive in a variety of soils, resist disease, and last a long time, and some oaks have leaves that turn a burnished red in fall.

To the British government in the 1600’s, trees, especially oak and white pine, were the frosting on the Colonial cake. English forests had been heavily logged, and timber trees had been pretty much wiped out by the 14th century, forcing England to import wood for its ship-building, furniture, and later, iron industries. America’s dense forests were ripe for logging, and oak lumber and pine trunks for ships’ masts became major American exports.  

Ecologists talk about “Ecosystem services” — the benefits a plant or animal provides to other members of its community. Oak and hickory provide plenty! 

They cool the landscape (farmers used to leave an oak or hickory in the middle of the fields they cleared so that they and their livestock could rest in the shade), and their leaves absorb pollutants from the air. Data from the US Forest Service suggest that oaks sequester more carbon than any other woody group in the continental US, which helps alleviate climate change. Their leaves slow heavy rainfall, minimizing erosion.

Oaks and hickories are important plants for wildlife. According to the National Wildlife Federation, more than 100 vertebrates in the United States eat acorns, which they call “the cheeseburger of the forest ecosystem.” Oak leaves are eaten by lots of insects, too – according to Professor Doug Tallamy, caterpillars of 534 species of butterflies and moths in the Mid-Atlantic States depend on oaks for food, and some eat nothing else. The small critters that feed on oak provide food for larger ones; birds and mammals nest in its branches, and both predators and prey find shelter in their leaves and in bark crevices. Hickories are equally important.  

white oak
red oak
bur oak

And, of course, for millennia, oaks and hickories have provided humans with medicine, dyes, shelter, lumber, shade, and food (acorns from the white oak group can be used right away, but acorns from red/black oak mature the following spring and must be processed first). Ink was made from oak bark and galls, and large hickories can be tapped for sap like maples. 

Oak gall

Fun Fact about Oaks: every two to five years, oaks produce an extra-large crop of acorns – it’s called a mast year. Right after a mast year, populations of acorn-eaters boom, but the next year, the acorn crop crashes. Acorn-feeders decrease again until the trees surprise them with the next bumper crop.

The strategy works because by the time the next mast year happens, there aren’t enough acorn consumers around to eat them all, so some become new trees. Weather conditions may be a factor in signaling a mast year, but the trees in a local area may communicate with each other chemically or through underground threads of fungus (mycorrhiza) to synchronize their timing.  Other kinds of trees, like hickories and maples, also have mast years.  The summer of 2012 was very hot and dry, and in 2013, a number of species responded by producing a bumper crop of seeds. The mast year picture, taken in 2014, shows the forest floor the next summer, carpeted with thousands of maple seedlings. 

Maple mast year

There’s an acorn mast year/white-footed mouse population/Lyme disease connection.

Another Fun Fact about Oaks:  Many years ago, the BugLady read Bill Bryson’s A Walk in the Woods, the story of his adventures on the Appalachian Trail.  In one chapter, he talked about how, when oak leaves are under attack by Spongy (Gypsy) moths, the trees will send out stress chemicals that oaks downwind can “read” and react to by upping the tannin content of their own leaves, making them less palatable to the advancing caterpillars!  She contacted her “Go-to botanist,” who confirmed what was then an emerging field of study (thanks, Jim).  The BugLady was in school back in the day of the dinosaur, when part of the definition of a plant was that it had no “nervous system” and so could not respond to stimuli.

The BugLady originally wrote this for the newsletter of the Lake Michigan Bird Observatory.

It’s National Moth Week!

Kate Redmond, The BugLady

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

Bug o’the Week – Bronze Jumping Spider

Bug o’the Week
by Kate Redmond

Bronze Jumping Spider

Howdy, BugFans,

On a walk at Spruce Lake Bog in May, the BugLady spied this Bronze jumping spider (Eris militaris, in the family Salticidae) (thanks, Mike) sitting on an unfolding alder leaf.  He spied her, gave her a firm look and then went on his way, apparently unimpressed.

Turns out that the Bronze jumper, aka the Bronze lake jumper (or Saltique militaire, if you’re in Quebec), can be seen across 80% of the country, plus Canada, making it one of the most widely-distributed Jumping spiders we have.  It likes suburbs and countrysides, and it lives in sunny areas where there’s vegetation to sun on, to hide in, and to hunt in, and it’s sometimes found in leaf litter on the ground.  It also likes agricultural areas, especially orchards, where it picks off crop pests.

The Bronze jumping spider is common enough and its contributions to agriculture are recognized enough so that the effect of pesticides on these spiders has been noted.  Exposure to insecticides may subdue both their behavior and their personality, affecting spatial memory and inhibiting learning.  Males may have trouble hunting, though they can still capture prey, while females may be too weak to catch prey. 

Eris was the Greek goddess of strife and discord, an apparent allusion to the not-exactly-smooth movements of jumping spiders.  The species name militaris (“soldier-like”) was chosen by Nicholas Hentz, the scientist who named it, because of the spider’s daring hunting behavior.

Males and females are dimorphic (“two forms”).  Males (body about ¼” long) have a light cephalothorax (front section) and a darker abdomen https://www.bugguide.net/node/view/2012703/bgimage, and females (not much bigger) are the opposite https://www.bugguide.net/node/view/1333539/bgimage (and look a bit “teddy-bear-ish” to the BugLady).  Their faces disarm even the spider-averse https://www.bugguide.net/node/view/2461050/bgimage.  

They do not spin trap webs but, as their name suggests, catch their prey by jumping at it.  Small bees, flies, and wasps are all fair game, and so are caterpillars, moths, crickets, leafhoppers, and other insects – and spiders – that they find on their journeys.  They acquire their prey by spotting it (their vision is very good and they notice everything), creeping forward, closing the gap until they are 1 to 20 cm away, and then jumping at it by pushing off with their back pair of legs.  As they start to jump, they fasten a line of silk called a dragline to catch them if their leap – or their prey – carries them over the side of whatever surface they’re on.  A jump can cover 10 to 20 body lengths.  They’re also known to leap into the air after a flying insect. 

They carry their prey to a safe spot to eat – in the daytime, a sunny spot with good visibility.  In the evening, they may opt for “carry-out,” bringing their immobilized prey to a leafy shelter where they will spend the night.  They groom themselves after their meal. 

In early evening, Bronze jumpers make simple shelters between leaves, often using silk.  They are sun-lovers that bask in the sun when they emerge from their shelters in the morning, and that stay in their shelters when the weather is cool, cloudy, or rainy. 

Bronze jumpers shelter under dead wood or loose bark or in man-made dwellings in fall, often in the company of other Bronze jumpers (they are not social, just tolerant), and they may overwinter there, in an insulated microhabitat lined with silk.  They emerge, almost-mature, in spring, and romance ensues.

When boy meets another Bronze jumper, boy or girl (he can recognize members of his species more than four inches away), he “stands on tiptoe” and does a little dance, waving his front set of legs and sidestepping.  If the object of his attention is a male or an immature female, it will depart, often chased by the dancer – it’s usually a flight, rather than fight, response, and males rarely come to blows.

His dance signals his fitness, and if a female is not interested, she may whack his waving legs with her legs.  If she’s impressed, the pair may cohabit in a silk shelter for a while.  She will produce and guard an egg sac.

The BugLady found this account in a Penn State Extension page about the Bronze Jumper under the heading “Medical Importance:”

“This species is not medically important.  (Note: The original author of this publication had personal experience in this regard. While attempting to get the spider to look at the camera by using his index finger to get the spider’s attention, the male pounced upon the fingertip, bit it, and hopped off. The pain was immediate and surprisingly distracting. After only 15 seconds, the pain was gone and no other symptoms developed.”).

Kate Redmond, The BugLady

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

Bug o’the Week – A Tale of Two Robber Flies

Bug o’the Week
by Kate Redmond

A Tale of Two Robber Flies

Greetings, BugFans,

The BugLady was walking at Riveredge Nature Center one day in mid-June when she spied a small Robber fly perched on a leaf, hanging onto its prey.  When she put the picture up on the monitor, she recognized the predator as a small (barely ½”) Robber fly named the Stripe-legged robber fly (family Asilidae).  Then she tried to figure out what it was holding.  It kind of looked like a midge, and that’s how she (uneasily) ended up labeling the picture.  Then, as she often does, she entered her dragonfly list for the day at the Wisconsin Odonata Survey (https://wiatri.net/inventory/odonata/) website and sent her butterfly list to the Wisconsin Butterflies page (https://wisconsinbutterflies.org/).  Mike Reese, who runs the site, is also interested in Tiger beetles and Robber flies, and he knew what the prey was.  Many thanks, Mike.

First, the predator, the STRIPE-LEGGED ROBBER FLY

North America is home to a wide variety of alien/exotic/non-native plant and animal species.  Along with famous invasives like Purple loosestrife, Garlic mustard, Emerald ash borers, and Spongy (Gypsy) moths (see https://sewisc.org/), we also have non-native species that keep their heads down and are not invasive – butterflies, daddy longlegs, orchids, and more.  The Stripe-legged, aka the Glassy-winged, aka the European Longhorn robber fly (Dioctria hyalipennis) is one of two non-native Robber flies.  The species name “hyalipennis” comes from the Greek word hyalo (“glass” or “clear”) and the Latin word pennis (“wing” or “feather”). 

Their original haunts were sun-dappled shrubby/woody areas, parks, yards, hedgerows, and field edges in western Europe and northern Africa, but they found their way across the Pond and were first spotted around Boston in 1916.  Today they are found throughout the northeastern quadrant of North America (plus, inexplicably, in Seattle and Denver).  They’re not uncommon in the areas where they occur, and they’re said to be somewhat gregarious.

Like other Robber flies, they spot their prey from a perch and fly out to grab it.  And, like other Robber flies, they may go after prey that’s almost as big as they are.

One source pointed out that as Robber flies go, Stripe-legged robber flies are not particularly spiney, but since many of the small insects they eat are soft-bodied, like flies, small moths, and leafhoppers, robust spines on the legs aren’t as critical.  They also tackle pygmy grasshoppers, bees, and wasps.  Matt Pelikan, who writes an excellent Nature column for the Martha’s Vineyard Times, describes it: “Perched glassy-winged robbers are constantly alert, and visibly track any object that flies near them, adjusting their stilt-like legs and pivoting their heads to keep the target in view. Fast-moving insects are left alone, but when a suitable target putters past, Dioctria launches and zeroes in on its victim. As with most robbers, a high percentage of attacks connect.” 

He continues, “The process is too fast to watch. The robber grasps its victim and rams pointed mouthparts into its body, injecting a blast of enzymes that both paralyze the prey and begin to break down its tissues. Robbers, with spindly necks, surely don’t have neck muscles that allow them to “peck” their way through a victim’s exoskeleton; I surmise that they grasp the victim with their legs and pull it against their beaks, with the hairs and spines on a robber’s legs being there to assure a firm enough grasp to do this.

…  It doesn’t take Dioctria long to drain a typical victim: after five minutes or so, the emptied husk is tossed overboard, and the robber fly resumes scanning for its next meal.

A Piper Cub in a family of fighter planes, the glassy-winged robber fly may be the shortest, lightest, least well-defended, and slowest-flying member of this group. You might think those traits would be disadvantages in a predator. But a lot of dead leafhoppers argue otherwise. Dioctria is perfectly adapted to find and catch a class of prey that is both abundant and vulnerable.” 

And the Prey? A PAINTED PIXIE

When Mike looked at the picture, he identified the prey as another Robber fly – at ¼”-ish, the smallest one we have, a Painted Pixie (Beameromyia pictipes) (pictipes comes from “picti” – painted- and “pes” – foot).  He went on to say that he has seen them around southern Wisconsin, and the BugLady takes off her hat to him – if anyone can spot a midge-sized Robber fly, it’s Mike. 

Sources generally conclude that there’s little information about the Painted Pixie because it’s rarely observed.  So, the BugLady backed up a couple of notches taxonomically to its subfamily, Leptogastrinae.  Species in the subfamily tend to be small and inconspicuous.  Some species tweak the general Robber fly MO and hover before picking up prey that’s sitting on vegetation.  Or spiders from their webs – the Leptogastrinae eat more spiders than other groups of Robber flies do.  Here are some spectacular (sub)family pictures https://robberfly.org/leptogastrinae/

The genus Beameromyia is a very small genus with 15 species in North America and only 24 worldwide.  Most of our species are found in the Southwest.  These are tiny, slender, long-legged flies that have variously swollen hind legs.  They’re found in the east and Midwest in the semi-open areas, where they feed on very small spiders and flying insects.

[Caveat emptor – one site that presented pictures and “facts” about the genus Beameromyia was, in fact, just plugging in generic Robber fly information, and stated that “As members of the Asilidae, these predatory flies are characterized by their robust build and predatory habits.”] 

In a monograph on the revision of the classification of the subfamily published by the American Museum of Natural History in 1957, Charles H. Martin wrote that the range of

Beameromyia pictipes “seems to be a narrow belt extending from Kansas to Maryland.”  Robber Flies of the Southeast lists their range as the Eastern and Midwestern US, where along with dappled woods and edges, their habitat includes old fields and grassy dunes

And the BugLady’s photograph of the two?  Right time, right place, right toys. 

Finally, a correction:  alert BugFan Tod noted that in last week’s salute to spring, the BugLady misspelled the name of the Duskywing, writing “Juvenile’s” Duskywing instead of Juvenal’s.  Juvenal was a Roman author of satirical poetry, and the BugLady has no idea how that connects with butterflies.  Thanks Tod.

Kate Redmond, The BugLady

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

Bug o’the Week – Spring Summary

Bug o’the Week
by Kate Redmond

Spring Summary

Howdy, BugFans,

Now that summer has arrived with a vengeance, it’s time to take a quick look back at some spring bug experiences.

BUMBLE BEE ON PINK LADY’S SLIPPER – A website about Wisconsin’s native orchids lists “naïve bumble bees” as pollinators.  Naive bumble bees.  Lady’s slipper orchids do not offer a nectar reward to foraging insects, but it takes a few visits to the orchids before a bee figures that out and looks elsewhere.

FIRE-COLORED BEETLE, in the family Pyrochroidae (which means “fire color”) seems like an odd name for a mostly-black beetle, but some members of the family are https://www.bugguide.net/node/view/1235995/bgpage, and many of the others have that nice, red thorax.  The BugLady saw it from afar, sitting on the tip of a skunk cabbage leaf – she’s been accused of using her zoom lens as binoculars, and she pleads guilty.  This contributor to bugguide.net got a far better picture https://www.bugguide.net/node/view/1796471. 

She thinks this is Schizotus cervicalis, who goes by the awesome name of Flaming pillow beetle (because of the males’ puffy, red thorax).  Fire-colored beetles have an interesting relationship with Blister beetles, which is explained in a BOTW about a related Fire-colored beetle in 2012 https://uwm.edu/field-station/bug-of-the-week/fire-colored-beetle/. 

DARK FISHING SPIDERS are big (leg-spread up to 3”), long-legged spiders that really get people’s attention. This one, found in late May, was about half-grown and was in the process of regenerating a leg.  Its ability to regrow legs depends on age and molting.  The small, new leg emerges after a molt and grows after each subsequent molt, but most spiders don’t molt after they become adults, so the new leg might not fully develop.  Spiders can generally get along just fine despite a missing leg. 

JUVENILE’S DUSKYWING – Duskywings are skippers (family Hesperiidae) and skippers are butterflies (though some sources still call them “butterfly-like”), although at one time they were considered a transition group between butterflies and moths.  Skippers tend to have large, chunky, hairy bodies in proportion to their short wings, and they have a tiny, “crochet hook” at the tip of their antennae.  They get their name from their quick, bouncy flight.  The Juvenile’s Duskywing is an early season butterfly that likes to perch on the ground. 

NORTHERN PAPER WASPS are the wasps that tuck disk-shaped, open-faced nests up under the eaves https://www.bugguide.net/node/view/2109317/bgimage.  Most are yellow and black (Nature’s warning colors) but some are reddish https://www.bugguide.net/node/view/2316444/bgimage. 

STAG BEETLES (Lucanus placidus) emerge from their underground pupal cases in late spring.  Adults live only a few weeks and are said to feed on flower nectar (the BugLady would like to see that) and on tree sap, and the larvae feed on decaying trees and roots (they don’t kill the trees, but they help to dispose of them).  Read about one man’s encounter with these lunker (1 ½”) beetles https://insectlab.russell.wisc.edu/2016/06/23/buckets-of-beetles/.

ACANTHOCEPHALA TERMINALIS (no common name) is a leaf-footed bug that can be seen over several generations from late spring through early fall, though the BugLady has never seen one this large in mid-May.  The flanges on its hind legs explain the “leaf-footed” part of its name, and its species name – terminalis – refers to the golden tips of its antennae.  It is in the True Bug order Hemiptera, and though it’s not officially a Stink bug, it can deploy a smelly chemical when threatened (though it would rather fly than fight).  This is the only genus member here in God’s Country.

Their nymphs are pretty cute, too https://www.bugguide.net/node/view/1644287/bgimage.

CRAB SPIDER ON VIOLET – The BugLady was surprised to see an adult Goldenrod crab spider decorating a violet in the first week of May.

Were there butterflies?  Yes.

MOURNING CLOAKS are, for butterflies, very long-lived – when you see one in May, it’s about 10 months old and at the end of its trail.  One of the few butterfly species that overwinter as adults, Mourning Cloaks are often seen during January thaws and maple sap season (they tuck themselves back into a sheltered spot when the cold returns), and they’re an early butterfly in the woods in spring.  How do they do it?  They’ve got a lot of insulating hairs; they use isometric exercises to warm the flight muscles in their thorax, and they count on tree sap and rotting fruit for food, rather than flowers.  It will mate, lay eggs, and die, and its caterpillars will eat, metamorphose, and fly for a while, but then it will aestivate (become dormant) to avoid the wear and tear of summer before returning to the air to finish out the year.

HOBOMOK SKIPPERS are the first of the skippers to hit the airways, appearing in sunny clearings and edges as the wild geranium starts to bloom.  They’re on the wing before the BugLady develops her annual case of “Skipper Brain” – for a brief time, she is (almost) positive of her skipper IDs.  Hobomok Skippers are part of a series of butterflies named by Thaddeus W. Harris and others after Native American chiefs. Hobomok was the “chief of the Wampanoag Indians, who helped the Pilgrims upon their landing in Plymouth in 1621.”

And were there dragons and damsels?  Oh, you bet, though the dragonfly season has gotten off to a very slow start!  The majority of invertebrates that the BugLady’s camera finds are dragons and damsels. 

EBONY JEWELWING – What would a spring report be without a spectacular male Ebony Jewelwing?  Along with very showy rubyspots https://www.bugguide.net/node/view/2178678/bgimage, jewelwings are in the Broad-winged damselfly family Calopterygidae (“beautiful wing”), the river damsels.  Don’t look for them around quiet ponds.  They put their beauty to good use in their showy courtship displays. 

DOT-TAILED WHITEFACE – No doubt that this is a whiteface – here’s the dot-tail https://www.bugguide.net/node/view/26379.

We were so busy celebrating National Moth Week last week that we neglected to celebrate the simultaneous National Pollinator Week!

Kate Redmond, The BugLady

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

Bug o’the Week – A Quartet of Moths

Bug o’the Week
by Kate Redmond

A Quartet of Moths

Greetings, BugFans,

In honor of National Moth Week, here are three lovely moths that the BugLady has found recently, plus one from BugFan Freda (the BugLady’s definition of a “lovely moth” includes being identifiable).

In the past, moth books, including Holland’s venerable, century-old Moth Book, upon which the BugLady cut her teeth, entomologically speaking, pictured moths in a pinned position, with the front wings stretched forward so that their trailing edge stands at right angles to the body, and the hind wing extends behind it.  Yes, this dorsal view makes visible the patterns on the upper surfaces of all four wings, but most moths just don’t sit like that out in the field, and posture can be a great clue in identifying them.  Newer guides, like the Peterson Field Guide to Moths of Northeastern North America and Sogaard’s Moths and Caterpillars of the North Woods show the moths at rest – wings extended in a V, wings folded, wings stacked over their bodies, or wings wrapped around it.   

Remember, the Order Lepidoptera includes both the butterflies and the moths, and although they are less charismatic, moths overwhelmingly outnumber butterflies by 180,000 species to 20,000 globally and by 11,000 species to 700 in North America.  Although numerous, moths are shy and retiring and most do no harm, so biographical information for many is scanty.

The DARK-SPOTTED PALTHIS, AKA the Angulated snout-moth (Palthis angulalis) is a poster child for how different a pinned specimen https://www.bugguide.net/node/view/1263477/bgimage can look compared to a live moth.  Even its dorsal view https://www.bugguide.net/node/view/2178817/bgimage doesn’t really match the gnarled and twisted side view.  Thanks to BugFan Freda for sharing.

Dark-spotted Palthis moths are in the family Erebidae and in the subfamily Herminiinae (which used to be a separate family), the Litter moths, so called because the caterpillars of many species feed on dead leaves.  They have a wingspan of about an inch, and there can be a lot of variation in color https://www.carolinanature.com/moths/palthisangulalis.html.  Males have long, sensory organs (palps) attached to their mouths that are sometimes called “a snout” https://www.bugguide.net/node/view/1291220/bgimage, and several authors said that they resemble jet planes because of the way the curled/folded outside edges of their swept-back wings.    

They’re found in woodlands across the eastern half of the continent, with some records in British Columbia.  Caterpillars https://www.bugguide.net/node/view/2485329 eat living or dead leaves, flowers, and fruits of a wide variety of woody plants like basswood, birch, alder, maple, willow, some conifers, and more, and some herbaceous plants like aster and goldenrod.  

The STRAW BESMA (Besma endropiaria) is in the family Geometridae, whose caterpillars are called the Earth-measurers or inch worms.  Straw Besmas are found in woodlands east of the Great Plains. 

Sogaard describes the caterpillars https://www.bugguide.net/node/view/1142291/bgimage as “looking like a reddish twig” and goes on to say that they are “prime examples of what was dubbed ‘vegetable disguise’ by Alfred Russell Wallace” (the naturalist/polymath who lived from 1823 to 1913, whose independently published theory of evolution through natural selection is said to have spurred Charles Darwin to collect his thoughts and publish on the matter).  They feed on a variety of hardwoods like alder, birch, oak, and especially sugar maple, and they overwinter as pupae.

The YELLOW-DUSTED CREAM MOTH (Cabera erythemaria), another Geometrid, is found in sunny woodlands and edges and thickety stream sides.  At first glance, it’s another little, white moth, but a second glance reveals fringed wings peppered with tiny, black dots and divided by subtle, yellow lines.  The BugLady couldn’t find any explanation of the species name erythemaria, which suggests that something is red, unless it refers to markings on the caterpillar.

Caterpillars https://wildcolumbia.org/wp-content/uploads/2023/03/original.jpg love willow leaves, but they also feed on birch and blueberry.  They overwinter as caterpillars.

(When the BugLady was researching the Yellow-dusted Cream moth, the always-excitable internet posed a few related questions, like “Are Yellow moths dangerous?” and “Are yellow moths poisonous?”  No and No.)

The DECORATED OWLET (Pangrapta decoralis, family Erebidae) looks (and sits) like a small butterfly and is another species whose unique posture would be lost in a pinned specimen.  The BugLady posted it on her Facebook page as an as-yet-unidentified moth and got an ID within hours (thanks, Robert).  It comes in a variety of colors and patterns https://www.bugguide.net/node/view/2265925/bgimage, https://www.bugguide.net/node/view/2412939/bgimage, https://www.bugguide.net/node/view/2017389/bgimage, https://www.bugguide.net/node/view/682515/bgimage, and researchers suspect that it is part of a complex of three sibling species – species that look the same but are “reproductively isolated” – they do not interbreed.  In other words, we may not be able to tell them apart, but they can.  They are close relatives that have recently diverged. 

They are found over much of Eastern North America, and their caterpillars https://www.bugguide.net/node/view/936111/bgimage eat blueberry and huckleberry (this one was found in a bog, surrounded by blueberry and huckleberry).  They overwinter as pupae.

Go outside – say hello to a moth.

Kate Redmond, The BugLady

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

Bug o’the Week – Wildflower Watch – Daisy Fleabane

Bug o’the Week
by Kate Redmond

Wildflower Watch Daisy Fleabane

Howdy, BugFans,

Daisy fleabane (Erigeron sp.) is blooming.  If you’re not familiar with it, the name “teeny daisy” – given to it by the BugLady’s then four-year-old, firstborn child – describes it well.

It’s in the Aster/Composite family Asteraceae, so each fleabane “flower” is actually a whole bouquet made up of a mass of tiny, central flowers called disc flowers and an outer rim of ray flowers.  But the Asteraceae like to mix things up – some family members, like dandelions, consist of only ray flowers, while others, like Beggars’ ticks, have very conspicuous disc flowers and inconspicuous ray flowers, and still others, like Blazing stars (Liatris) and thistles, have only disc flowers.

The word “bane” in a plant’s name usually predicts trouble – for someone, anyway.  In this case, flies, gnats, fleas and other bothersome insects were (allegedly) repelled by the smoke when the plant was burned, and the flowers were dried and added to mattress stuffing and tied into brooms. 

Astringent, anti-inflammatory fleabane plants, flowers, and oils were widely used medicinally by both the Native peoples and the European settlers to treat migraines, gout, sore muscles, epilepsy, skin issues, “female problems,” fevers, heart troubles, and more, and the dried flowers were used as a snuff to break up nasal congestion.  The Lakota name for fleabane translates to “sore mouth medicine.”  It was also one of the plants that were smoked in pipes.

Bugs like it, too.  As always, the BugLady found insects and spiders who came to rest, to eat, and to be eaten, and with all that going on, some pollination happens, too.  Today’s episode is a bit moth-heavy because we are approaching National Moth Week. 

BI-COLORED PYRAUSTA MOTH – The BugLady has been seeing these small moths (wingspread just over ½”), but they don’t stick around to have their portraits made – they make a rapid, scrambling flight and then tuck themselves in under a leaf.

A CRAB SPIDER waiting for a little carry-out.

WAVY-LINED EMERALD – If you’re going to feed in plain sight in the daytime, you need a disguise.  This caterpillar makes its own by clipping bits of fresh petals and sticking the pieces to spines on its back https://www.bugguide.net/node/view/1038322/bgimage.  When the vegetation dries, the trim makes it hard for birds to spot them.  Here’s what it will look like when it grows up https://www.bugguide.net/node/view/2260155/bgimage.

A ROBBER FLY enjoying a meal.

IRIS WEEVIL – The BugLady has seen more Iris weevils on fleabane and ox-eye daisies than she has on irises.  Adults chew into the iris flower’s ovary and oviposit there.  While the adults are feeding on the flowers, pods, and seeds, the larvae within eat seeds and their surrounding tissues.  This doesn’t affect the health of the plant, but the weevils are not welcomed by people who want to harvest iris seeds.

KATYDID – Katydid nymphs are awesome.

RIPIPHORUS BEETLE – One of the “wedge-shaped” beetles in the family Ripiphoridae (which comes from a Greek word meaning fan carrier, a reference to the fancy antennae sported by the male).  Ripiphorus fasciatus is a beetle dressed like a fly, a disguise that undoubtedly allows them to cozy up to other insects on flower tops.  Females oviposit there, and their unusually-energetic larvae stand erect on the flowers, ready to board ground-nesting, solitary bees so that they can be transported back to the bee’s egg chambers.  There, they enter an egg chamber and then enter the larva in the chamber and consume it from the inside.  Look fast – males live for a single day, and females for not much longer.

SYRPHID FLY – Some syrphid/flower/hover flies are chunky bumble bee mimics, but some are delicate and beautifully-patterned, and when they land on your skin (to check out its salt content) your skin feels minutely cool.

ARCTIC SKIPPER BUTTERFLY – Officially the BugLady’s favorite skipper because although it is, like many skippers, brown and orange, you can’t mistake it for any other species.  They have a preference for bluish/purplish flowers, but fleabane works, too.

SPOTTED THYRIS MOTH – This chunky, little moth has a wingspan of just under a half-inch, so it fits easily on the fleabane’s disc flower.  Although they’re a day-flying moth, they’re easily overlooked, because they’re slightly smaller than a honeybee, and so they’re probably more common than we realize.  The Prairie Haven blogger (https://www.prairiehaven.com/?page_id=8920) says that “They looked like tiny crumpled butterflies.”

TACHINID FLY – Lots of tachinids are bulky, bristly, and house-fly-shaped.  Not Cylindromyia.  Tachinid flies are parasitic flies, many of which are considered beneficial biological controls of agricultural pests.  Not Cylindromyia.  This wasp-mimic targets a few species of predatory stink bugs that are, themselves, biological controls, plus some of the giant silk moths (Cecropia, Polyphemus, etc.).  

BLACK AND YELLOW FLOWER BUPRESTID – A.K.A. the Yellow-marked Buprestid, Hairy Yellow-marked Buprestid, Spotted Flower Buprestid, Beautiful Flower Buprestid, and Flat-headed Sapwood Borer.  Buprestids, many of which are tough-looking, bullet-shaped beetles, are known as the Metallic Wood-borers (though this one is dull and hairy rather than shiny).  Adults eat pollen and nectar and are hard to spot on yellow flowers; larvae are wood borers. 

All of the stars of today’s episode have also starred in their own BOTWs, which you can find by typing into the search box “UWM Field Station Arctic Skipper,” or “Iris weevil,” or whatever. (it took the BugLady an embarrassingly long time to figure that out).

Go outside – check the fleabane.

Kate Redmond, The BugLady

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

Bug o’the Week – And Now for Something a Little Different XIX – American White Pelican

Bug o’the Week
by Kate Redmond

And Now for Something a Little Different XIX American White Pelican

Howdy, BugFans,

2026: The BugLady spent the morning watching pelicans; photographing pelicans on the water, on the beach, and, in small squadrons, in the air; and editing pictures of pelicans.  They’re having a moment in her neighborhood at the edge of Lake Michigan.  There are two floating about far offshore right now – brilliant in the sunlight.

Here’s an article she wrote about them two years ago for the newsletter of the Lake Michigan Bird Observatory.

2024: Just before 3:00 PM on October 6, the last new species of the Big Sit! was spotted from the tower – two White Pelicans that were working their way north along the shoreline. A single bird flew south over the tower the next day. 

Wait! – pelicans live where the land touches the oceans, right? Well, yes. And – no. Brown Pelicans are certainly creatures of salt water, and when one shows up in Wisconsin, it’s a big deal, but American White Pelicans are native not only to the coasts but also to the Upper Midwest and to the prairie potholes of the northern Great Plains.

They’ve been present in Wisconsin for a long time, though it’s not known whether the birds reported by Indigenous tribes and early European settlers were breeding or migrating. They made a big target for the early settlers, despite the fact that, as one said “they have an oily flavor, whether alive or dead, which is so disagreeable that it is impossible to eat them.”  Wisconsin’s first modern breeding records occurred in 1995 (Green Bay) and 1997 (Horicon Marsh), and the newcomers probably hailed from North Dakota. For an interesting history of White Pelicans in Wisconsin, see https://swibirds.org/fff/2020/6/19/american-white-pelican.  Here’s a map of their present range https://www.allaboutbirds.org/guide/American_White_Pelican/maps-range.

The American White Pelican’s scientific name, Pelecanus erythrorhynchos, means “red-billed pelican.  The German naturalist who named it based his description on the writings of an English ornithologist who called it the Rough-billed Pelican. John James Audubon, waxing poetic, added “American” to its name, saying, “In consequence of this discovery, I have honored it with the name of my beloved country, over the mighty streams of which may this splendid bird wander free and unmolested to the most distant times, as it has already done in the misty ages of unknown antiquity.“

White Pelicans typically feed on minnows, shiners, carp, and suckers, but they’ll eat game fish, tadpoles, crayfish, and salamanders, and sometimes they adopt commercial catfish ponds. Unlike Brown Pelicans, they don’t plummet into the water from the sky; they hunt while swimming on the surface.  White Pelicans often forage alone, but a group may cooperate to encircle a school of small fish, drive it toward shore, and then share the results.  They sometimes steal food from other birds, even from the beaks of other pelicans that are feeding their young. During the breeding season, they often feed at night, locating fish by touch. 

A bird this size has few predators, but foxes and coyotes do damage in breeding colonies, and ravens, gulls, Great Horned Owls, Red-tailed Hawks, and eagles prey on eggs and nestlings.

After a courtship that includes strutting, bowing, head swaying, circling in the air, and jabbing at potential nest spots, pelican pairs settle down in communal nest areas, often on islands for protection. They lay two or three eggs but usually fledge only one young. Competition is stiff – it takes about 150 pounds of food to launch a young bird – and the first chick to hatch may eventually eliminate its nest mates (siblicide). Chicks can crawl by two weeks, walk by the end of three weeks, and fly by 10 weeks. When they’re about three weeks of age, chicks leave their nests and gather with other chicks in a group called a “crèche,” but they return to the area of their old nest to be fed.

FUN FACTS ABOUT WHITE PELICANS

  • The North American bird with the largest wingspread is the California Condor (9.5+ feet). With a nine-foot wingspan, the White Pelican is the second largest, and at almost 30 pounds, is one of the heaviest flying birds.
  • White Pelicans are hardy enough to overwinter in Wisconsin if they can find open water. They can be seen on this bird cam on the Mississippi near LaCrosse very early in spring and into late fall  https://explore.org/livecams/raptor-resource-project/mississippi-river-flyway-cam.
  • Adult White Pelicans have a vocabulary of grunts, but nestlings are more vocal, making loud begging calls. Even pelican embryos get into the act, squawking from inside the egg when they are too hot or too cold. To hear Pelican sounds https://www.allaboutbirds.org/guide/American_White_Pelican/sounds.
  • White Pelicans don’t have a brood patch – an area of bare skin where body heat is transmitted to their eggs. Instead, the parents incubate eggs by placing the webs of their feet over them.

DID YOU KNOW – that a pelican’s beak can, indeed, hold more than its belly can? A lunge fills the pelican’s stretchy pouch with a few gallons of water, and hopefully some fish, too. It tilts its head to let the water drain out of the bill, and the fish are swallowed right away. Pelicans need three or four pounds of fish each day.

On another note, June is Wisconsin’s Invasive Species Action Month. For more information see the Southeastern Wisconsin Invasive Species Consortium (SEWISC) https://sewisc.org/, and https://dnr.wisconsin.gov/topic/Invasives?utm_source=newsletter_101&utm_medium=email&utm_campaign=sewisc-quarterly-newsletter-summer-2026.

Go outside – whack an invasive.

Kate Redmond, The BugLady

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

Bug o’the Week – Wetland Homage – Waterlily leaf beetle

Bug o’the Week
by Kate Redmond

Wetland Homage Waterlily leaf beetle

Greetings, BugFans,

2026: The final installment in National Wetlands Month, though the BugLady would argue that wetlands should be celebrated every month.  The BugLady attempts to photograph this burnished beetle everywhere she sees them – some in aquatic settings as they peruse the flowers of yellow water-lilies, and others on marsh marigolds and skunk cabbage in the adjacent swamps.  They are not huge – most would have to stretch to reach a half-inch – and they often appear to be gold.

2013: The BugLady can hardly pass by a water lily without taking a picture of it, and she confesses that she sometimes “sanitizes” the leaves somewhat during the editing process, Photo-Shopping out some of the mess of frass (Bug poop) and aphid exuviae (shed skins) and holes and discolorations that characterize the leaves of water lilies (especially white water lilies) in mid-summer.  She was reminded recently by BugFan Caitlin that water lily plants are the Center of the Universe for an amazing community of critters that live both above and below the leaf surface.  Someday she will track the colonization of the leaves from the beginning of the season and write a BOTW about it.

Although they are sometimes (confusingly) called Long-horned leaf beetles, Waterlily leaf beetles are in the huge Leaf beetle family Chrysomelidae, and not the long-horned beetle family (equally confusingly, there’s another leaf beetle with the same name).  The subfamily Donaciinae (the aquatic leaf beetles) contains five genera and about 55 species (mostly in the genus Donacia, which today’s beetle probably is, too.  You’d need a microscope and a higher pay grade than the BugLady’s to determine the species).  Donacia comes from Donax, which is Greek for “reed,” and they’re called “reed beetles” in Great Britain. 

WLBs can be found in “weedy” ponds and lakes and very slow streams all over North America.  The adults are leggy, up to a half-inch long, often metallic, with antennae about half as long as their body; they are jumpy and can move fast, and they’re a little camera shy.  The layer of silky hairs that covers their undersides repels water in their often-soggy habitats (settle down, there).  Find them on the surface of a variety of emergent and floating-leaved plants.  Some are generalist feeders and others are plant specialists; some are generalists while the leaves of their favorite plant are still submerged, but they make a bee-line for it when it emerges.  Adults enjoy the leaves of water lilies, arrowhead, potamogeton, and water milfoil, some sedges, rushes and reeds, and they may, like this beetle, eat pollen.

When it’s egg-laying time https://www.bugguide.net/node/view/2309633/bgimage, females of many species of WLB chew a hole in a lily leaf, insert the end of their abdomen, and glue their eggs to the underside of the leaf in concentric arcs – like a mini-rainbow.  Some other species accomplish the same thing while perched on the edge of the lily leaf, and a few crawl up the plant stem, while still others climb under the leaf and down the plant stem. 

According to a report by Paul S. Welch in the Annals of the American Entomological Society, Vol. 9 (1916), the “aquatic” moth (its caterpillar is aquatic) Nymphula maculalis (the Polymorphic Pondweed moth) (really!) takes advantage of the holes excavated in yellow water lily by the female Donacia.  The moth also arranges her eggs on the leaf’s undersurface in up to six concentric arcs, using the spots around the rim of the hole that are not occupied by beetle eggs.  In his study, the author didn’t find a single mass (clutch?) of moth eggs that was not associated with a Donacia egg hole.

The BugLady has never seen a WLB larva (your typical small, whitish, C-shaped beetle grub), probably because most spend their larval lives plugged into a submerged plant stem, never “coming up for air.”  How do they do that?  The eggs hatch in about 10 days, and the larvae drop down through the water column, typically finding the roots and rhizomes (underground stems) of their host plants in the muck (some also feed on stems and petioles).  In the words of Ann Haven Morgan in her Field Book of Ponds and Streams, “When the stems of aquatic plants are broken beneath the water, a flood of air bubbles comes pouring to the surface from the air spaces within them” [that’s why, BugFans, the leaves of floating-leaved vegetation float instead of getting dragged under water – the stems are buoyed up by pockets of air].  “……MacGillivray and others found stems with dozens of little Donacia larvae hanging to them feeding upon the plant tissues, and all breathing air, though they were three or four feet below the surface of the water.”

Pennak, in the venerable Freshwater Invertebrates of the United States, enlarges on the concept.  Insects typically breathe through paired pores called spiracles that are located on the sides of the abdomen.  In the WLB larva, the only spiracles that are operational are the two at the end of the abdomen, and each of these two pores is associated with a sturdy spine.  The larva uses the spines to excavate holes in plant stems, which taps into their inner air pockets, and the air flows out over the spiracles.  Pennak notes that both ends of a larva will be embedded in plant tissue simultaneously. 

Fast-forward to the day, a few weeks later, when a mature grub is ready to pupate.  Using silk produced by glands in its mouth, the larva creates a waterproof cocoon near where it has been feeding.  How do you build a dry haven when you’re underwater?  You tap into the same air, present in the plant tissues, that has been sustaining you as you feed.  You snug your cocoon up against a stem and cut holes through it and into the plant and you allow air to leak in.  As the final touches are being put on the cocoon, the water has been driven out.  O little engineers! 

Although it develops into an adult fairly quickly, the WLB aestivates inside its cocoon until it emerges at the beginning of the next summer.  In a study of a European Donacia, researcher Christian Otto suggested that this arrangement may help the beetle avoid periods of low dissolved oxygen concentrations or may help the beetle time its appearance with the start of the growing season.  When it’s time to exit, the beetle breaks through the cocoon’s tip, carrying enough air under its elytra (wing covers) and belly hairs to sustain it on its trip to the surface. 

Go outside – find a wetland.  Look at stuff!

Kate Redmond, The BugLady

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

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