Bug o’the Week – Stilt-legged fly

Greetings, BugFans,

The BugLady had a “Stop the Presses” moment as she was writing this week’s BOTW.  When she hiked down to the mailbox, she saw a fly that she had never seen before, from a family she’s never seen before, skating over the top of a leaf, and she bumped it to the head of the line.  She photographed it badly, but here’s a good image https://bugguide.net/node/view/190234/bgimage.

In last week’s episode we considered a beetle that mimics a bumblebee; this is a fly that is imitating an ichneumon wasp https://bugguide.net/node/view/435323/bgpage (and no one messes with wasps), and some of its relatives are ant-mimics https://bugguide.net/node/view/84097/bgimage.

It’s a Stilt-legged fly/Small-footed fly in the family Micropezidae, a family with only about 30 species in North America and some 600 species worldwide (they’re a different bunch than the tiny, iridescent Long-legged flies https://bugguide.net/node/view/1543910/bgimage in the family Dolichopodidae).  Stilt-legged flies are most diverse in the tropics, where their larvae are dung-dwellers.  They’re famous for raising their short, front pair of legs so that they look like antennae as the flies walk around https://bugguide.net/node/view/789265/bgimage; their actual antennae are pretty short.  They live in damp and dappled wetlands and woods.  Kaufman, in hisField Guide to Insects of North America tells us to look for them “crawling slowly about the base of trees, or on low foliage.”

Micropezids feed on decaying organic matter or in plant roots as larvae (the larva of an Australian species lives in the water of a pitcher plant and eats decaying invertebrates that it finds there).  Some adults are predaceous and others eat rotting fruits and droppings of birds or other animals.  As a group, they fly below the radar, and there are a lot of gaps in our knowledge of their natural history.

This stilt-legged fly, Rainieria antennaepes (no common name), is the only Rainieria in North America.  According to bugguide.netantennaepes refers to the fly’s habit of passing off its legs as antennae.  It’s found east of the Rockies and into southern Canada.

Sometimes, as it walked around, the fly would bow its head down toward the leaf surface https://bugguide.net/node/view/1031146/bgimage, allowing it to suck up food with its forward-facing, “vacuum cleaner” mouthparts, which look like a tiny gas mask (see the last picture at https://sites.duke.edu/dukeinsects/insect-orders/diptera/taeniaptera-trivittata).

About its life history, the BugLady could find little – according to the website americaninsects.net, “Larvae often develop in decaying leaves or other rotting plant material. The pupa is made from the final larval skin, and so the pupa resembles the last larval instar.”

Even though parts of its life are a mystery, the BugLady found a number of videos featuring the adults.  In the first, even though the BugLady has admired The Early Birder’s great insect shots, the “semaphore” he refers to looks like grooming behavior to her https://www.youtube.com/watch?v=Ba3inwK11Ys.  Check out the video of a stilt-legged fly snacking on a bit of cheese at http://bugoftheweek.com/blog/2019/4/1/wasp-or-fly-stilt-legged-flies-mimetic-micropezidae, and this, from another of the “Bug of the Week” series out there http://blog.growingwithscience.com/tag/rainieria-antennaepes/.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Once Upon a Fungus

Greetings, BugFans,

When the BugLady was walking in the woods at Riveredge the other day, she found some plate-sized, stocky, very aromatic, gilled mushrooms growing out of the ground – possibly one of the (glorious name) Fetid Russulagroup.  They were pushing up under last year’s leaf litter; some were partly covered, but some were discernable only as an upward swelling of oak leaves.  The cap of the Russula is concave, so water and other stuff collects in it.  A microclimate.

She saw something moving on the rim of an “over-the-hill” fungus, and she had the good grace to think “what’s a bumblebee doing in a place like this?”  The AMERICAN CARRION BEETLE is counting on that reaction, and it enhances the illusion by buzzing its wings as it flies.  No-one messes with bumblebees.

Turns out there were a bunch of American Carrion beetles on that and other mushrooms, on the cap, and deep in the flesh and gills (she also photographed a half-dozen on some carnivore scat, but she may not be able to show that shot in polite company).

Carrion beetles have a fascinating lifestyle, which was chronicled in the early days of BOTW https://uwm.edu/field-station/carrion-beetles/.  They perform ecosystem services in the form of corpse-removal, but they also feed on rotting fungus and animal droppings.

[Sidebar: Russulas can be hard to tell apart; many are considered inedible, but some are mild enough to eat, and some have a spiciness that sneaks up on you (but remember: “There are old mushroom hunters, and there are bold mushroom hunters, but there are no old, bold mushroom hunters”).  They get their nutrients from the roots of trees.  Sometimes the mushrooms, which are the fruit of a large, underground system of mycorrhizal strands that connect with plant roots, grow in a straight line above a tree root.  Just as the fungi get their food from a tree root, the lovely, parasitic woodland flower Indian pipe (which was blooming in the woods, but not nearby) gets its nutrients from a variety of Russula hosts (for which the Indian pipes are dubbed “mycorrhizal cheaters”).  They’re not alone – beetles, slugs, some rodents and deer eat Russula mushrooms.]

When she looked at the mushrooms more closely, the BugLady discovered that there was more going on.  Along with the gang of American Carrion beetles were a few red-rimmed MARGINED CARRION BEETLES https://uwm.edu/field-station/margined-carrion-beetle/.

And, a GOLD AND BROWN ROVE BEETLE, which the BugLady swears is not luminescent, though the yellow hairs on its rear are iridescent.  Find its story here https://uwm.edu/field-station/gold-and-brown-rove-beetle/.

And, between the layers of oak leaves, an ANT NURSERY, with workers poised to rescue the eggs when, suddenly, their roof disappeared.

And a cloud of tiny flies, attracted to the mushroom by its very mushroomy odor.

And the exuvia (shed exoskeleton) of a spider that paused to molt there.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Summer Survey 2019

Salutations, BugFans,

The BugLady hopes that you’ve been getting out on the trail and drinking in the lushness of the summer.  If this heat and humidity are the “new normal,” we might as well get used to it.

Insect photography in summer uncovers the common themes of eating and reproducing (sometimes, in the case of ambush bugs, simultaneously).

Paper wasp –

A Northern paper wasp has a super power – she chews on plant materials, mixes the cellulose with saliva, and spits out paper that she forms into a hemispherical, “open-faced” nest (https://bugguide.net/node/view/1554212/bgimage) on plants and under eaves and porches; the large and dangerous football-shaped paper nests are made by bald-faced hornets.  Look for her on flowers, feeding on nectar and collecting small insects for the larvae.  Having collected prey, according to bugguide.net, “The wasp then malaxates, or softens the food and in doing so absorbs most of the liquid in the food. This solid portion is given to older larvae and the liquid is regurgitated to be fed to younger larvae.”  Bugguide also tells us that “P. fuscatus has unusually variable color patterns, allowing individual wasps to recognize each other’s faces.”

Planthopper nymph

Been seeing plant stalks that are a bit fuzzy these days?  It’s not your glasses – if you look closely, you’ll see that they are tiny bugs.  This one is the nymph of a planthopper, probably in the family Flatidae.  For more about them, meet the other (original) “Bug of the Week,” this one written by an actual entomologist: http://bugoftheweek.com/blog/2013/1/9/junes-snowfall-planthoppers-family-flatidae-missing-video.

Syrphid/hover/flower fly

Syrphid flies are bee mimics that can be found feeding harmlessly on nectar and/or pollen on flower tops.  The BugLady loves the exquisite patterns on their abdomens.  “Hover fly” comes from the males’ practice of hovering in the air, hoping to attract the attentions of a female.  They are great little pollinators.

Jumping spider meets syrphid fly

Jumping spiders are beautiful, bold little spiders that look you right in the eye and don’t back down (though they’re great at zipping around to the back of a leaf when they see a camera). Find out more about them at https://uwm.edu/field-station/jumping-spider/.  We all are, potentially, someone else’s lunch.

Syrphids again

When the BugLady photographed these delicate, green aphids, she did not notice the pale larva just north of them on the stem until she put the picture on the screen.  It’s the larva of a syrphid/hover/flower fly, and it eats aphids.  Death from above.

Land snail

It’s humid here by the lake – gotta’ keep moving or stuff will grow on you.  The wall-snail population is possibly a sign from the cosmos that it’s time to round up a pressure washer.  Or get more snails.

Ambush bug

The BugLady loves these small-but-mighty ambush bugs that hang out on flower tops and often take prey that’s much bigger than they are.  They grasp in firmly with their hook-like front legs and inject meat tenderizers.  Here, its catch is a sweat bee.

Rainbow Bluet

What’s a summer survey without an Odonate?  This incredible creature is about 1 ¼” long from his peachy face to the sky-blue tip of his abdomen.

Creepy aphids

First of all, this clump of aphids was being protected by some very alert ants, and when the BugLady brushed against the plant, she suddenly had about 20 ants on her hand and sleeve (she’s a wee bit ant-averse).  The ants were there for the honeydew secreted by the aphids, which is a staple in the diet of many ant species.  But then, the BugLady put the aphid picture up on the screen and saw the creepy “eyes.”  BugFan Freda pointed out that the aphids are plugged into the stem, drinking plant juices, and their eyes are facing down.  The glowy “eyes” are the twin tailpipes (cornicles) at the rear of the insect).  But still…..

Baltimore Checkerspot

Baltimore Checkerspot caterpillars feed on a late-blooming wetland plant called turtlehead.  In fall, the gregarious caterpillars make a communal web on their food plant and stay inside, inert, for the winter.  When they emerge in spring, they need to eat some more before they’re ready to form a chrysalis, but there’s no turtlehead around, so they pick alternate hosts, including white ash.

They’re spectacular with wings open https://bugguide.net/node/view/1245900/bgimage, and the caterpillars are orange and black, too https://bugguide.net/node/view/1076839/bgimage.  Orange and black were the colors of the livery worn by the servants of Lord Baltimore at the time that the early settlers were arriving in this country, and it’s his name, not the city’s, that’s attached to the oriole and the butterfly.

Thread-waisted wasp

Like the paper wasp, these wasps cruise the flower tops looking for nectar (she also finds sustenance in extra-floral nectaries – for the amazing EFN story, see https://uwm.edu/field-station/ants-in-my-plants/).  Solitary where the paper wasp is social, each thread-waisted wasp makes her own mud nursery for her offspring, and she provisions it with small insects and spiders, depending on her species.

The Black and yellow mud dauber (Sceliphron caementarium) (caementarium means “mason, or builder of walls”) is found in a big chunk of North America.  Her nest may contains about as many as 25 brood chambers (https://bugguide.net/node/view/1480753/bgimage), each cached with a few dozen spiders.

Black firefly

Fireflies (lightning beetles is a more accurate name) wow us with their nocturnal light show, blinking or streaking across the sky with a species specific signal to the females waiting below (https://uwm.edu/field-station/lightning-beetle-again/).  But, the Black firefly (Lucidota atra) is a day-flying firefly and would have to use a lot of energy to compete with the sun (males may glow briefly immediately after they emerge from their pupal case).  If he cannot glow, how does he woo?  By flying close to the ground, searching for the “perfume” of the pheromones released by the female.


The BugLady is sickened by the number of dead ash trees sticking out of wetlands and uplands, and this is the beetle that’s responsible.  The Emerald ash borer is an immigrant from northeast Asia that left its natural checks and balances at home.  Its larvae burrow in and feed on the living tissues just under the bark of an ash tree, creating squiggly tunnels called galleries.  Eventually, there are so many galleries that the tree’s “plumbing” is disrupted and it can’t move nutrients up and down the trunk.

Thanks to the EAB we have a new indoor sport during the Polar Vortex – figuring out whether it has gotten cold enough for long enough to kill the majority of the larvae.  Not yet.

Katydid nymph

With a little luck (OK – a lot of luck) this infant will grow up to be a good-sized bush katydid, probably this one https://bugguide.net/node/view/1275677/bgimage.  in the meantime, it looks like a tiny, jeweled creature.

Go outside – look for bugs!

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Tree Crab Spider

Howdy, BugFans,

The BugLady was checking around the edge of a gravel parking lot near the Ozaukee Washington Land Trust’s Lake Twelve property (because there are bugs there, too) when she found this beauty (it took two trips and two different cameras to get a few almost-in-focus shots – sometimes it’s like that).

She had two immediate reactions: 1) what is it? And 2) it looks like an octopus clinging to a reef!

It’s a crab spider in the tree crab spider genus Tmarus, probably Tmarus angulatus (thanks, as always, to BugFan Mike).  Mike says that there are a few documented records of this species in Wisconsin, but they are probably more common, it’s just that we don’t typically hunt for spiders in trees.  And, of course, they seem to have the “camouflage” thing figured out.

Crab spiders (family Thomisidae), best known for the species that ambush insects on flower tops, are long-time favorites of the BugLady https://uwm.edu/field-station/an-album-of-crab-spiders/.  They get their name from their tendency to hold those four, extra-long front legs in a crab-like pose and for their tendency to move sideways.  Crab spiders don’t spin trap webs to catch their prey, they ambush it on the hoof.  They paralyze their prey and then introduce (bugguide.net says “vomit”) digestive enzymes into it, wait for its innards to soften, suck out the tenderized tissue, and throw away the empty.

They do spin silk, protecting themselves from a fall by playing out a drop line as they hunt, and this Tmarus spider was guarding her eggs in a chamber she created by bending and webbing together a slender day lily leaf.  She will stay nearby for about a month to protect her eggs from predators.

About the genus Tmarus the BugLady could find very little.  The spiders appear regularly on state biodiversity lists, and there are a bunch of scholarly articles about new species being discovered in different countries around the world (one article from Sri Lanka was titled “Twigs that are not Twigs”).  The BugLady was gratified to find that the spectacular Tmarus marmoreus spider in Australia is, indeed, nicknamed the Octopus spider https://www.brisbaneinsects.com/brisbane_spiders/OctopusCrabSpider.htm.  It hunts by dangling from a line of silk with its front legs poised and ready.

Their knobby bodies are usually well-camouflaged on bark and other vegetation, where they look like buds or broken twigs.  The Field Guide to the Spiders of California and the Pacific Coast States tells us that with “forelegs along either side of a stem, they wait for an insect to wander between them.”  According to the Kansas School Emporium’s Checklist of Kansas Crab SpidersTmarus spiders have been observed eating ants, which most spiders avoid.

Tmarus angulatus, sometimes called the Tuberculated crab spider, is small spider with a body about a half-inch long (females are larger than males) that is found across the US and southern Canada.  Some are pale and some were dark, and the BugLady saw a picture of a gravid female with a dark cephalothorax (front end) and a pale abdomen, with a caption that said that she looked like a spittlebug nest.  Well, maybe.  Here’s a little gallery of shots of Tmarus angulatus looking like the flower head of a rush https://bugguide.net/node/view/646754,

pale-colored https://bugguide.net/node/view/1168821,

in the open https://bugguide.net/node/view/1516412/bgimage,

a male https://bugguide.net/node/view/1516412/bgimage,

oriented with its legs up https://bugguide.net/node/view/1238420/bgimage,

very well camouflaged https://bugguide.net/node/view/1043877/bgimage,

and https://bugguide.net/node/view/1223511/bgimage,

and a nice egg-to-spiderling series https://bugguide.net/node/view/298740/bgimage.

Tmarus angulatus was described and named in 1837 by Baron Charles Athanase Walckenaer (1771 – 1852), who is described as a French civil servant and scientist.  In fact, he squeezed the pursuits of several lifetimes into his 80 years.  He was a geographer who was named Conservator for the Department of Maps at the Royal Library in Paris, was Secretary for life of the Academie des Inscriptions et Belles Lettres (where he introduced the French to the English genre of the biography), was a co-founder of the Societe entomologique de France, member of a group of early anthropologists called the Societe des observateurs de l’homme, was mayor of a section of Paris, found a map of the Americas drawn by Columbus contemporary Juan de la Cosa (the earliest known map of the new World), and was an arachnologist and entomologist (author of Histoire naturelle des insects).

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Majestic Long-horned Beetle

Howdy, BugFans,

The BugLady is always excited when she finds an insect she’s never seen before – even more so when it’s a giant, orange and gray “Holy S@#&!” beetle. 

She was moseying along the trail at Riveredge Nature Center at the beginning of July when she saw a flash of orange in the vegetation.  A big flash.  She craned and fidgeted and crossed her fingers while the beetle crawled around, revealing itself by degrees.  After posing for a few shots, it flew out noisily and landed on her jeans for a second, and then moved on. 

It’s a spectacular beetle, (Dr. John Hamilton, writing in The Canadian Entomologist in 1885 says that “this appears to be a rare Cerambyan, and among the choicer.”), but there’s not much information out there about it (it isbig enough and beautiful enough, but apparently, it’s not bad enough to warrant attention). 

To put it in context – with about 390,000 species (25,000-plus in North America), beetles (order Coleoptera) are the largest order in the whole animal kingdom, not just in the Class Insecta.  Long-horned beetles (family Cerambycidae), those darlings of the beetle world (because https://bugguide.net/node/view/199424/bgpage, and https://bugguide.net/node/view/674692/bgimage, and https://bugguide.net/node/view/128536/bgpage, and https://bugguide.net/node/view/1379236/bgimage, and more), number about 30,000 species worldwide with only about 1,000 in North America.  The MLHB is in the Flower longhorn subfamily Lepturinae, a group of sometimes-dramatically-wedge-shaped longhorns (https://bugguide.net/node/view/131694/bgpage) that hang out on flower tops by day.  There are a dozen species in the genus Stenocorus in North America – more elsewhere.

At 1 ¼” the Majestic long-horned beetle (Stenocorus schaumii) is indeed majestic.  It comes in two colors (https://bugguide.net/node/view/1499994/bgimage) and some are more chiseled than others https://bugguide.net/node/view/6759/bgimage (the BugLady’s MLHB was not svelte), and females are notably larger than males.  It is mostly eastern-ish – bugguide.net says New Brunswick to North Carolina to Manitoba to Oklahoma.  A number of the search hits were from eastern Canada, in French. 

Cerambycid larvae are vegetarians; some are pests of living plants, some feed inside dead or dying wood, and the interests of many do not collide with ours.  MLHB larvae feed/develop in ash, beech, maple, serviceberry, and other hardwoods, and the adults eat nectar and pollen. 

The MLHB was described by LeConte and is one of several insects named for German entomologist Hermann Rudolf Schaum, a go-to guy for all-things beetle in the mid-1800’s, who wrote and corresponded prolifically with American entomologists.  Schaum apparently believed that the Continent should be the clearinghouse for insect classification.  In a history of American entomology called Brethren of the Net: American Entomology, 1840-1880, author Willis Conner Sorenson tells us that “Schaum…..objected to the notion that ‘American insects ought to be described by American entomologists.’  The result, he said, had been the proliferation of isolated descriptions, a practice that had been characterized by Schaum’s colleague Erichson, as ‘the nuisance of science.’  Schaum regretted that American entomologists had added to this nuisance.” 

Entomology as Blood Sport.

Kate Redmond, The BugLady 

Bug of the Week archives:

Bug o’the Week – And Now for Something a Little Different – Slime Molds

Hi, BugFans,

The BugLady wrote this article for a recent newsletter of the Friends of the Cedarburg Bog (an organization that would love your support).

Slime molds are strange and wonderful life forms that can exist as tiny, single cells, but can also form a mass of cells that acts like an organism – and moves!

Back in the days when fungi (now placed in their own Kingdom) were classified as plants, slime molds were classified with the fungi. Today, slime molds defy exact classification (slime molds can’t be plants because slime molds eat!). They’re placed in a catch-all group that some people call the kingdom Protista, made up of often unrelated single-celled or colonial single-celled organisms that have similar structures and life styles. Australian researcher Chris Reid calls Protists “a taxonomic group reserved for everything we don’t understand.” They’ve been around for a billion years.

They may be so small that they live their whole lives under our radar, moving slowly through the soil; or they may aggregate to form bright yellow or white, spongy blobs on the forest floor, or pink spheres on decaying wood, or tiny, brown cattail shapes on branches. Or, they might start as the first and end as the second. They have great names, like wolf’s milk, tapioca, pretzel, white coral, red raspberry, chocolate tube, dog vomit and scrambled egg slime.

Two of the main groups are the cellular slime molds (Dictyosteliida) and the plasmodial or acellular slime molds (Myxogastria). Both kinds start out as tiny, single-celled amoeba-like critters in soil or rotting material, both can use chemicals to communicate, and both, at some sign from their environment, may congregate and go into reproductive mode, transforming from a single-celled organism to a giant “megacell” (one scientist calls them “a bag of amoebas”). They feed on bacteria, algae, and fungal spores and help organic materials to decompose. They are eaten by many small animals (there are little, shiny, brown beetles apparently feeding – and cavorting – in the pink slime mold), and some are said to be edible by humans.

Their orientation is deliberate; their ability to pick the most direct route to food mimics the efficient layout of expressways and railroad systems; they were the inspiration for the Sci-fi movie “The Blob;” the math that describes their orderly aggregation is applied to video games; and some can anticipate change, learn to solve mazes and remember. And when they are chopped up, they reassemble and remember.

For more information, see

https://www.scientificamerican.com/article/brainless-slime-molds/ and

https://www.pbs.org/newshour/science/the-sublime-slime-mold and


Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – The Dance Fly

Howdy, BugFans,

The BugLady loves these fancy little flies (and their habitat preferences, for the damp and the dappled, are similar to hers).  Dance flies are abroad in June, and they are one of the BugLady’s “nemesis bugs;” they seem to object to being in focus, but this small spider managed to capture one.  They starred in a BOTW episode at the very end of June, ten years ago: https://uwm.edu/field-station/dance-fly-family-empididae/

Go outside – look at bugs.  Tell the BugLady what you see.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Iris Weevils at Play

Greetings, BugFans,

As long-time BugFans know, the BugLady gets a kick out of weevils.  She found these cute little Iris weevils (Mononychus vulpeculus) recently, scampering around on flowers at the Ozaukee Washington Land Trust’s Cedarburg Environmental Study Area (CESA) site (for directions to and maps of their properties, see https://owlt.org/visit-our-preserves).  Obviously, iris weevils are not exclusive to iris – the BugLady sees them on ox-eye daisy and daisy fleabane (she did find two of them sitting on an iris petal that had tiny holes punched in it, but they were camera shy).  Iris weevils were half of an episode about weevils that was posted four years ago https://uwm.edu/field-station/gardening-with-weevils/

For a story about another CESA adventure, see https://uwm.edu/field-station/the-ants-of-cesa/.

Support your local Land Trust. 

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Luna Moth

Greetings, BugFans,

The BugLady’s favorite insect is the Tiger Swallowtail (Mom likes me best), but in the crowded field for second place, the Luna Moth is pretty close to the top.  

Luna moths (Actias luna) are in the Giant Silkworm/Royal Moth family Saturnidae (of previous BOTW fame https://uwm.edu/field-station/giant-silk-moths-family-saturnidae/), whose family members have ringed eyespots reminiscent of Saturn.  The LM’s name came from eyespots that resemble moons (eyespots that make predators ponder whether their target might be different than they originally thought).  Actias is a small genus with about two dozen species worldwide, and the LM is the only American species.  They are found in wooded areas east of the Great (on rare occasions, LMs have made their way to Europe).

And giant they are, with wingspreads that often exceed four inches.  Males and females look pretty much alike; her egg-laden abdomen is larger than his, and his antennae are fancier than hers.  Both have what’s called quadripectinate antennae, which means that they are comb-like, with four “tines” per unit of the antenna https://bugguide.net/node/view/754599/bgimagehttps://bugguide.net/node/view/293789/bgimage, and the female https://bugguide.net/node/view/426762/bgimage.  Their long, twisted tails are said to interfere with bat radar, and they also present a false target for predators – bats manage to snag some LMs, but many others get away after the bat mistakenly grabs them by those spectacular tails.  

(LMs make photographers sweat (“please don’t let me screw up, please don’t let me screw up….).  Here are some photographers who didn’t screw up https://bugguide.net/node/view/20728/bgimage,https://bugguide.net/node/view/617459/bgimagehttps://bugguide.net/node/view/655366/bgimagehttps://bugguide.net/node/view/917529/bgimage, and (possibly posed) https://bugguide.net/node/view/1532344/bgimage).

Warming weather signals them to emerge from their cocoons, which they accomplish with the aid of an enzyme (named cocoonase!!) that they secrete to soften the dried silk and of a hard spur at the base of each front wing, which they use to break through it; here’s a video and of an LM eclosing (emerging) https://www.youtube.com/watch?v=FECzFIRPeD4, and some still shots https://bugguide.net/node/view/481690/bgimage.  Then they pump up their wings and begin their short lives as adults.  Females emit a pheromone that calls males to her perch.  His feathery antennae allow him to sense a mere handful of scent molecules from two or more miles away and to follow the increasingly concentrated scent trail to her.  Lunas are nocturnal, and most mating occurs after midnight.   

Adults have neither mouth nor gut, and they live only about a week, dying soon after they reproduce.  There is one brood per year here in God’s Country, and two or three in the south. 

Females lay between 200 and 400 eggs, singly and in clumps, on host plants.  LM caterpillars feed on the leaves of birch, hickory, walnut, maple, and sumac, and add sweet gum, pecan, and persimmon in the south (they aren’t considered forest pests).  They show regional favoritism – LMs in our area prefer birch and do badly if moved to a different food plant.  One theory is that LM caterpillars are capable of processing the defense chemicals produced by their host trees, and they may become specialists in detoxifying a particular species.  Young caterpillars https://bugguide.net/node/view/1434316/bgimage are knobbier than older ones https://bugguide.net/node/view/1191475/bgimage.  

Mature caterpillars become dark red before pupating; they drop to the ground and use silk to wrap themselves in a leaf for the winter https://bugguide.net/node/view/1191457/bgimage, camouflaged in the litter of the forest floor.  LM pupae are not passive – if they are disturbed, they will move noisily within their cocoon.  Jim Sogaard, writing in Moths and Caterpillars of the North Woods tells us that “The pupa has a clear ‘window’ through which even dim light can stimulate the brain.  Photoperiod likely contributes to breaking diapause [the suspended animation of winter].  If a cocoon is moved, the pupa within may noisily reorient itself to the light.”  Here’s a nice stage-by-stage series: https://bugguide.net/node/view/945719

A two inch long LM caterpillar looks like a feast for any predator that finds it despite its green camouflage, but the caterpillar has a bag of tricks that includes rearing up on its back legs, warning its would-be attacker by making clicking sounds with its mandibles, and then regurgitating the noxious contents of its intestine. 

LMs are not common, and they are becoming less so.  Their natural predators include bats, owls (one source told of a Screech Owl that fed on males that came to visit a female calling from a branch), spiders, and toads. 

Human activities also impact them: 

  • A tachinid fly imported in 1906 to control gypsy moths now parasitizes the caterpillars of almost 200 species of native butterflies and moths, including the giant silk moths.
  • Habitat loss due to urban street trees being cut and deciduous woods becoming more fragmented.  The caterpillars can’t adapt to non-native tree plantings.
  • Pesticides that affect not only the leaves that the caterpillars eat, but also the immobile pupa, and even the short-lived adults.  
  • Light pollution – LMs are strongly attracted to lights at night, exposing them to predators and, with the clock ticking loudly, distracting them from the task at hand.

Fun Luna Moth Fact – a bunch of butterflies have been featured on US postage stamps, but in 1987, the LM became the only moth (before or since) to be so honored.

Just in case you still haven’t seen enough LM images, https://www.marylandbiodiversity.com/viewSpecies.php?species=345

Look for them in the month of June. 

To paraphrase the Bard, “O brave new world, that has such creatures in’t!

Kate Redmond, The BugLady

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Bug o’the Week – Water Boatmen and Backswimmers Rerun

Salutations, BugFans,

Life is busy, and besides, May is National Wetland Month, so here’s a rerun from ten years ago.  A few new words and pictures. 

Water boatman

The BugLady will visit these guys together because even though they are, in a sense, photo-negatives of each other, they are often mistaken for one another (until you know the secret handshake). The majority of aquatic animals, from orcas to Mergansers to muskies to water boatmen tend to be dorsally dark and ventrally light (have dark backs and light bellies).  This coloring is protective because a predator looking down from above has to distinguish its dark-backed prey from the dark water surface, and a predator looking up from below sees a light belly against a surface that reflects the light of the sky.  The backswimmer, which spends its life rowing around belly-up, flip-flops the usual color scheme and has a dark belly and a light back. 


These two aquatic, boat-shaped, less-than-a-half-inch-long, “True Bugs” (Order Hemiptera) are not in the same family, and the water boatman also departs from the usual mouthparts and diet of its compatriots, but they have many similarities.  They are found in still waters – preferably with aquatic plants – including ponds, lake edges, sewerage ponds, bird baths, and even swimming pools (lots of websites devoted to getting rid of water boatmen and backswimmers in swimming pools), and they are more active in the dark than in the light.  They locomote via rowing movements of their flattened third pair of legs (backswimmers) or second and third pair of legs (water boatmen) and are often seen swimming or grabbing plant stems in a head-down position. They are strong fliers, although the up-side-down backswimmer must climb out of the water and flip over onto its belly before it can spread its wings and take off.

Both bring a tank of oxygen with them as they swim underwater.  The backswimmer stores air in two hair-covered troughs on the ventral side of its abdomen (it can stay underwater for as long as six hours), and the water boatman wraps a bubble of air under its wings and around its abdomen and also picks up dissolved oxygen from the water (it is so buoyant that it must grab vegetation in order to keep from floating to the surface).  Both overwinter as adults, and some water boatmen may remain active under the ice.  The males of both groups stridulate – rub rough area on their front legs against their head – “chirping” underwater to attract mates. 

Backswimmers (family Notonectidae) are piercer-predators that kill and suck the bodily fluids out of any prey they can subdue – invertebrate and vertebrate alike – including tiny tadpoles and fish fry (but big fish eat backswimmers).  Each set of legs is used for a different function – the front pair for catching their prey, the middle pair for holding the prey tight, and the flattened, hairy third pair acts as oars.

These little “Davids” will sometimes go after Goliath, piercing the leg of a human swimmer or wader, a habit that has earned them the name of “water bee” or “water wasp.”  It is a painful, burning bite that can have lasting effects in those who may be “susceptible to poisons,” according to Anne Haven Morgan in the Field Book of Ponds and Streams.

The often red-eyed Water boatmen (Family Corixidae) are a bit smaller than backswimmers.  Collector-gatherers, they swim along the bottom of the pond, head down, in search of food, and they use their front pair of legs to scoop it up.  Lacking the standard piercing beak issued to other aquatic true bugs, they ingest living material – diatoms, algae, protozoa, nematodes, small insects – that they find when they stir up debris on the bottom of a body of water. Some suck juices from algae. 

The eggs and the adults of water boatmen are eaten by birds and by humans (an Egyptian and a Mexican delicacy, according to some references) and were said to have been introduced to England as a food source.  The Handy Bug Answer Book by Dr. Gilbert Waldbauer recounts how bundles of rushes that are put into ponds in Mexico as a substrate for water boatmen to lay their eggs upon are removed, dried, and beaten to loosen the eggs.  The eggs are then cleaned and ground into flour to make a cake called “hautle.”

Besides their surprising edibility and the fact that they are said to smell like bedbugs, the water boatman’s only other claim to fame is that the males of some species make ultrasonic mating calls with what Monty Python would call their “Naughty-bits.”  Do not try this at home.

Kate Redmond, The BugLady

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