Bug o’the Week – Dung Beetle

Salutations, BugFans,

 

Sometimes, the secret of getting a good picture is “Right time, right place, right toys.”  The BugLady has been longing to do an episode on dung beetles – they’re amazing insects, and they live right here in Wisconsin, but clearly, she has not been in the right place at the right time, kicking over the right clods (first dictionary definition).  Thanks to BugFan Freda for pictures of an international dung beetle, which will stand in for Wisconsin species.

“Dung beetle” refers to beetles whose lives are intertwined with dung, but the term is not exclusively a taxonomic one.  True, most of its practitioners belong to the beetle family Scarabaeidae and the subfamily Scarabaeinae, but the name is also applied loosely to any beetle that makes its living in dung.  In Wisconsin, that includes a member of the Clown beetle family Histeridae and a member of the Water scavenger beetle family Hydrophilidae, who swims in dung, but whose relatives swim in water.

 

Researching the dung beetle is like researching a rock star.  There are True Facts, YouTube videos, Facebook, kids’ pages, and even a graphic novel or two!

 

Because they have Super Powers.

Like many scarabs, dung beetles are drab, stocky, and well-armored, some with a horn or an exaggerated “brow” that’s used in fighting, and with legs adapted for gripping, digging, and pushing.  They use their antennae to catch the scent of excrement.

 

Though they don’t especially like cold weather, dung beetles live in a variety of different habitats (deserts, grasslands, agricultural lands, and woodlands) on all continents but Antarctica.

 

Why are dung beetles dung beetles?  Because, as adults and as larvae, they eat and live, in and around animal droppings.  They prefer the droppings of herbivores and omnivores, which tend to be somewhat under-digested.  Adults eat the liquid portion, not the roughage, and the larvae feed on the solids.  Some species eat carnivore poop, fungi or decomposing fruits.  They don’t drink.

 

They meet and mate around dung.  Dung beetles are divided into three groups, depending on style – dwellers, tunnelers, and rollers.  Dwellers keep it simple – adults don’t excavate the soil or manipulate the dung, they just lay their eggs on top of a manure pile.  The larvae hatch and feed within the maturing manure pile, but the adults move to one that is fresher and wetter.

Tunnelers dig into the soil below a dung pat and make tunnels and egg chambers.  The male hauls bits of dung into the tunnels, and the female arranges them (it stays fresher underground) and lays eggs.  Both parents may stay in the manure with the larvae, and the male uses his headgear to defend his female, food and family from rival males with prolonged, underground pushing contests.  Tunnelers dodge some of the parasites and predators that find “dwellers.”

 

It’s the Rollers that most intrigue us.  An adult male locates a pile of good stuff (not too dry), breaks off some pieces, and compacts them, forming a ball.  This he offers to a female, and if she’s willing, they roll it away to a likely spot, watching as they go for rival beetles that may try to steal it (early naturalists thought that the other beetles were just helping the happy couple).

 

When they find a soft substrate, they bury the brood ball by hollowing out the space below it so it sinks into the ground.  After mating, the male leaves to sow his wild oats elsewhere, and the female makes a few more brood balls and lays a single egg in each, sealing them by smearing them with a paste of saliva, feces, and dung.  In some species, she stays to tend the grubs, which are described as “six legs and a mouth.”  She only lays a handful of eggs in her lifetime, and she works to ensure their survival!

 

Dung balls are also made and buried as food caches.

 

Dung beetles provide a variety of important ecological services (one of which is that without them we’d be knee-deep in, well,……).  They aerate the soil, recycle nutrients, improve water circulation, and disperse seeds, all of which encourages plant growth and improves conditions for grazing animals.  Fewer cow pats means less habitat for dung-loving, cow-biting flies (one cow pat can generate 3,000 flies).  And they break down and prepare the dung for species that will use it after they do.

DUNG BEETLE FUN FACTS

  • Instead of searching for their supper, some smaller species ride around on their suppliers and wait for a deposit to be made.

 

  • On the Great Plains, a wonderful owl called a Burrowing Owl (kind of the meerkat of owl species http://www.birdweb.org/birdweb/bigger_image.aspx?id=3889&type=p) collects the droppings of large grazers and places then around the entrance to its underground home.  Beetles find the dung and do their thing, and the owls have a steady supply of protein morsels.

 

  • A dung beetle may fly 30 miles to find dung, can roll a ball that weighs up to 10 times its weight, and can bury dung that is 250 times heavier than it is in a single night.

 

  • Dung beetles use celestial signals to chart a course from Point A to Point B.  Diurnal species roll their dung balls in a straight line, navigating by the sun (going around obstacles and then correcting).  Nocturnal species use polarized moonlight, and one species even uses the Milky Way to orient.

 

  • In various parts of Asia, dung beetles are used medicinally or are eaten.  In ancient Egyptian beliefs, the forming, transporting, and burying of a dung ball was a metaphor for the daily renewal of the sun.

 

Do dung beetles light your fire?  Find out more about them in this BBC Earth video by the venerable David Attenborough: https://www.youtube.com/watch?v=Zskz-iZcVyY,

 

And in this TED talk: https://www.mensaforkids.org/teach/ted-connections/dance-of-the-dung-beetle/,

 

and in this bulletin about dung beetles in Wisconsin: https://fyi.extension.wisc.edu/wbic/files/2016/08/Dung-Beetle-Ext-fact-sheet-final.pdf,

 

and in this article about the amazing dung beetle-nematode connection (it’s not gross – promise): https://www.theatlantic.com/science/archive/2018/10/dung-beetles-sexually-transmitted-worms/571804/.

 

Kate Redmond, The BugLady 

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

Bug o’the Week – Asian Multicolored Ladybug Redux

Greetings, BugFans,

 

The BugLady heard a funny sound while she was reading the other night, the kind of small thunkthunkthunk that made her wonder if there might be a small leak in the roof.  After a little reconnoitering (and, mercifully, dry fingers) she traced the sound to a ladybug that was bouncing off of the inside of the lampshade by her chair.  First (live) Multicolored Asian ladybug of the year.

Please enjoy this rerun of an episode from a few years ago – some new words and new pictures.

 

We didn’t do it,” say the websites of Departments of Natural Resources in a number of states, trying to make it very clear that they are NOT releasing Asian ladybugs in order to feed Wild Turkeys.  In fact, a Kentucky site declares emphatically that the state of Kentucky has never released them, but points a finger at neighbors to their South who have.  (In Wisconsin, the rumor is that the DNR stocks rattlesnakes to control turkeys – also false, on so many levels).

 

Multicolored Asian ladybugs (Harmonia axyridis) need no introduction – they’ve been around for a century (but especially for the last 30 years), and we know them by many names – Southern, Japanese, Harlequin, Halloween, and Pumpkin beetles, plus Aziatisch lieveheersbeestje (Holland), Asiatischer Marienkafer (Germany), and in Britain, jokingly, the Many-named ladybug.  Plus a few words that wouldn’t get past the censors.  The BugLady is intrigued by the genus name, Harmonia (which the beetle shares with a plant) but could find no explanation for it.  There are three Harmonia beetle species on our continent; all are introduced and well-established, and the Multicolored Asian ladybug is the most widely distributed.

The name “ladybug” is, of course, a bit misleading, since these are beetles (Coleoptera), not True bugs (Hemiptera), so “ladybird beetle” is more accurate.  There are close to 500 North American species in the ladybird beetle family (Coccinellidae) (from the Latin “coccinus” (scarlet) which comes from the Greek “kokkos” (berry)), and many of their lifestyles are similar.  See https://uwm.edu/field-station/ladybugs-three/ to find out more about the natural history of ladybugs.

 

There’s some discussion about when and how the Asian ladybug was finally established in North America.  It was brought to California in 1916 to control aphids but died off, was reintroduced there in 1964 and 1965, and it was released in a dozen Southern and Atlantic Seaboard states plus Nova Scotia between 1978 and 1982.  Each time, it did its job for a season or two, but then failed to thrive.  A number of sources cite a release in Louisiana in 1988 as the one that “took,” and the beetle subsequently traveled to almost all corners of the continent under its own steam (apparently, it doesn’t like the far, northern Rockies).  The alternate theory is that the successful colonizers arrived without fanfare in the Ports of New Orleans and Seattle and seeded themselves.  Whatever the truth, the Asian ladybug became common in the Midwest about 20 years ago, in the Northeast 25 years ago, and in the Northwest 30 years ago, and its numbers have grown considerably beyond “abundant.”  The Audubon Society Field Guide to North American Insects and Spiders, published in 1980, does not mention it at all!

On its home turf in the Far East, the Asian Ladybug feeds in forest and orchard trees, eating aphids (50 to 60 per day, say some sources, and up to 5,000 in a lifetime), and a few other small, soft insects, plus insect eggs, and it was deployed against soybean aphids in Japan (both the adults and the larvae are carnivores).  Those same soybean aphids, immigrants from Japan, made their first North American appearance – in Wisconsin, in fact – in 2000.  In the US, the beetle is used to control aphids in orchards (it’s very important to the pecan harvest), on roses and other ornamentals, and on agricultural crops including soybeans, alfalfa, corn, and tobacco, lessening the need for insecticides.  It also has a fondness for native lady beetles, and in fall, the Asian ladybug may be omnivorous.

 

The predators that kept their numbers in check in Asia were left far, far behind, and other than a few parasitic wasps, almost nothing goes after Asian ladybugs here.  Their red/red-and-black colors tell birds and other potential predators to think twice.  What are they advertising?  Along with some other beetles like lightning and soldier beetles, ladybugs ooze hemolymph (the insect equivalent of blood) that contains a bad-smelling, bad tasting chemical from their leg joints in order to discourage predators (it’s called reflex bleeding).  The chemical occurs in higher concentrations in the hemolymph of Asian beetles than it does in native beetles, and the Asian ladybug also manufactures a designer chemical called harmonine, which is antimicrobial.

At 5 mm to 8 mm long (9/32”), the Asian ladybug is a bit larger than its native cousins.  There are at least 16 different color phases (see http://bugguide.net/node/view/397), from red to orange to utterly plain to densely-spotted (one source said that a beetle with lots of spots is more likely to be a female).  They have reddish-brown legs, and most individuals have a black “letter” on the prothorax (the first of the three segments of the thorax) – either an “M” or a “W,” depending whether the beetle is coming or going.  The larva is likened to a tiny, spiny alligator.  In good weather with plentiful food it takes about a month to grow from egg to adult, and there are several generations per summer.  They overwinter as unmated adults – in Asia, they seek out crevices in tall, sunny, light-colored rock faces.

So – granted that this exotic beetle does a really good job of controlling equally exotic aphids on important crops, is there another side of the coin?  Let’s unpack a few sentences from the preceding narrative.

 

It has a fondness for native ladybugs.”  A dramatic decline in populations of native ladybugs has followed the arrival of Asian ladybugs, simply because it’s such a super competitor.  It has no compunctions about cannibalism; it eats a lot of aphids, robbing native beetles of food; diseases that afflict native ladybugs bounce off the Asian ladybug; and it even carries a microbe that kills the competition.  In Minnesota, the populations of three native ladybugs have plummeted.  Citizen Science, anyone? http://www.lostladybug.org/participate.php.

In fall, the ladybug may be omnivorous.”  And it especially likes to feed on sugary, ripening grapes, usually taking advantage of an opening in the fruit made by a bird or wasp.  The beetles get caught up in the harvest and pressed with the grapes, and whole batches of wine and grape juice have been tossed – even recalled from stores – due to the subsequent “ladybug bouquet.”

 

They overwinter as unmated adults.”  A few sites call it a “Home Invasion.”  On warm, sunny days right after the first crisp days of fall, they look for those ancestral crevices in those ancestral light-colored cliffs and find –-the sunny sides of light-colored buildings that are insufficiently sealed, allowing entry.  They just want to be warm and dormant all winter, and then they want to leave in spring.  They don’t breed or chew on the houseplants or carpets or the dog or the dog food or the floor joists – in fact, they (allegedly) don’t feed at all.  The BugLady’s not so sure about the no-eating part because she finds them in the compost bucket and around the sticky rim of the honey jar, but maybe hers just haven’t settled down to the ascetic life yet.

 

Sometimes there are astronomical numbers of the things.  They swarm.  It literally “rains beetles.”  They gather by the thousands in attics and walls.  Ladybugs use a chemical attractant called an aggregation pheromone to summon a crowd, and that pheromone persists, guiding future generations to the spot.  Their hemolymph stains surfaces and their odor persists – one source describes it as the sour smell of rotting leaves (this will get us ready for the Brown marmorated stinkbug, though).

 

Other than the odd nip, they don’t injure humans (Cowboy up, BugFans – their “jaws” are tiny and your skin is tough), though some people are allergic to them.  One sufferer, then the head of the Entomology department at a Kentucky university, reported runny eyes and clogged sinuses after contacting the hemolymph; other people experience asthma or contact dermatitis.

 

Ladybugs are for sale in garden stores and websites (there are elaborate instructions about preparing the garden so that the ladybugs don’t fly away home).  Although some sites don’t say which species they’re supplying, most sell the native Convergent ladybug (Hippodamia convergens) which are captured in the wild in their winter aggregations.

 

DNA studies tell us that Asian ladybugs in America were introduced from Asia, but Asian ladybugs in Africa, South America, and Europe came from eastern North America!  The United Kingdom’s Ladybird Survey laments that “Despite the American experience, the animal was also released into Italy and elsewhere in Europe.”  It’s been spotted in England, and the word is out to monitor native UK species.  Humans are, indeed, slow learners.

 

And, yeah – we did do it.

 

The BugLady

Bug o’the Week – Spotless Antlion – a Tale in Three Parts

Howdy, BugFans,

 

PART ONE – THE BACKGROUND:

As we all know, there’s a huge difference between looking and seeing.  The BugLady has a wooden pier across the top of the dune that protects her from Lake Michigan.  One day, at the end of June, she looked down and had an “Oh, Duh!!!” moment when it finally registered that the little pits in the sand at the top of the dune were the handiwork of a fascinating insect called a doodlebug or antlion.

Eight years ago, she wrote about antlions in the person of the Spotted-winged antlion (mistakenly using the term “nymph” interchangeably with “larva” to describe the immature antlion – please disregard).  Anyway, read the amazing story about how they dig pits and capture supper at https://uwm.edu/field-station/spotted-winged-antlion/, and watch a great video of same at https://www.youtube.com/watch?v=tcGjPItaKEg.

Some antlion highlights:

 

Antlions/doodlebugs are named for their immature stage, and there is no separate name for the adults, which don’t eat ants.  They are in the family Myrmeleontidae, which is in the Order Neuroptera (the “nerve-winged” insects), an order that has some unique members like

lacewings https://bugguide.net/node/view/114661/bgpage,

and mantisflies https://bugguide.net/node/view/1273550/bgpage,

and owlflies https://bugguide.net/node/view/1230894/bgimage, and more, but which no longer includes the dobsonflies (hellgrammites), alderflies, and fishflies (now in order Megaloptera).

 

The “doodle” in “doodlebug” refers to the squiggly trail that is left by a pit-digging larva as it walks around (backwards) looking for a place to excavate.  Doodlebugs are usually found in places that are somewhat sheltered and are soft underfoot, like fine-grained soil, sawdust, tree holes, and, yes, dunes.

Adults look like damselflies, only more fragile; they are weak, crepuscular/nocturnal flyers that come in drab colors and have conspicuous antennae (here are some good pictures https://bugguide.net/node/view/115388)https://bugguide.net/node/view/552173/bgimage).  Their larvae are the stuff of horror films – hairy, short-legged, and pear-shaped, with impressive, toothed mandibles that are not wasted on vegetables https://bugguide.net/node/view/264599/bgimage, and https://bugguide.net/node/view/611552/bgimage.

Adults are short-lived (maybe a month), but the larvae are not.  Eggs are laid in a soft substrate, and when they hatch (in about a month) the larvae start to feed.  Depending on food supply, they will spend between one and three years as larvae, molting three times before they pupate in a silk cocoon.  They’ve been at it for 150 million years.

 

Doodlebug larvae feed on small invertebrates, but not all species dig pits – some ambush their prey above-ground (and those species walk frontwards, not backwards).  In his Guide to Observing Insect Lives, Donald Stokes suggests that we drop an ant into a pit and watch the action.  Several BugFans have confessed to the BugLady that they did this and then felt such remorse about the almost-inevitable Death from Below that they helped the ant to escape.  A doodlebug injects toxic chemicals into its prey with its hollow “fangs,” pre-digesting the tissues and allowing the antlion to imbibe its prey’s liquefied innards. Adults eat pollen, nectar, and/or very small, soft insects; not much is really known about their feeding habits, but they sport impressive bristles on their legs.

Some birds have figured out that there’s something edible at the bottom of an antlion pit, and the BugLady read an account of a wasp that parasitizes doodlebugs by allowing herself to be grabbed, using her heavily armored hind legs to hold open those lethal jaws while she inserts an egg in the doodlebug’s neck, and then escaping, leaving her eventual larva to feed on doodlebug.  And there’s also a bee fly whose larvae parasitize antlion larvae and pupae.

 

PART TWO – THE DELIBERATION:

After the lightbulb finally went on, the BugLady established a Doodlebug Sanctuary and spent some time trying to photograph the pit-makers.  She saw the adult in mid-August, about six weeks after she recognized the pits, and by mid-September, the larvae had stopped refreshing their pits after rainstorms (which could be their normal phenology, but we had lots of rain about then.  We’ll see).

There are only about a half-dozen antlion species in Wisconsin, so coming up with an ID should be easy, right?  One problem she encountered is that one antlion species looks pretty much like the next to the BugLady.  Another is that species’ scientific names keep appearing and then totally disappearing from the literature.

 

She narrowed it down to two possibilities – Myrmeleon immaculatus, widely distributed in Wisconsin and in the US, and the much less common Cryptoleon signatum/Brachynemurus signatus.  Most (but not all) sources say that antlions in the genus Brachynemurus chase their prey rather than making pits, and Myrmeleon immaculatus is listed in a WDNR bulletin as the only pit-builder in the state.  Both are listed for Sheboygan County in a 1972 survey (https://scholar.valpo.edu/cgi/viewcontent.cgi?article=1173&context=tgle), which contains a lovely account of light-trapping Brachynemurus signatus in the sand dunes of the county.  Brachynemurus signatushas an abdomen that is much longer than its wings, but the adult that the BugLady photographed was only minutes old, and so may not have been done expanding or have developed its “finished colors.”

 

PART THREE – SO, IT MUST BE MYRMELEON IMMACULATUS:

The BugLady found a common name for Myrmeleon immaculatus in a reference from 1897 – the Spotless antlion.  Its diet consists mainly of ants, but it will consider anything that it can overpower in its pit, like spiders, flies, mites, small beetles, and caterpillars.  It will also consider cannibalism, especially when pits are densely spaced, and adults that emerge and walk across the sand looking for something vertical to climb must negotiate a minefield of occupied antlion pits on their journey.

 

Doodlebugs decide where to dig based on microclimate (soil texture and temperature are big factors), not on a survey of potential prey availability, and they if they guess wrong, they have to move to a more populated neighborhood.  Larvae that make small pits capture small prey (and ignore large prey that wanders in), and doodlebugs that make larger pits accept a greater diversity of prey sizes.  Hungry larvae dig smaller pits.

 

Eggs are laid in sheltered spots and are camouflaged by sand and debris that stick to them because of the tacky substance Mom coats them with.  The pupal case also seems to be disguised as a sand heap https://bugguide.net/node/view/556979/bgimage.

 

On his bugeric blogspot, Eric Eaton says that you can become a doodle bug whisperer! “Folklore states that if you lean over a doodle bug pit and repeat the phrase ‘doodle bug, doodle bug, come into view’, it will spit sand and move. There is some truth in the legend. Doodle bugs respond to vibrations and the human voice can cause just the right amount of vibration to spring an antlion to action.”

 

Kate Redmond, The BugLady

Bug o’the Week – Gray Field Slug

Salutations, BugFans,

 

The BugLady found this impressive (1 ½” to 2”) slug climbing around on her cottage in early October.  It has been almost 11 years since we last considered slugs (time flies!).  For a quick Slugs 101 review, see https://uwm.edu/field-station/slug/.  Recent BugFans please note that slugs, while not insects, are fair game because BOTW uses the kindergarten definition of “bug,” not the entomological one.  Thanks (as always) to the very versatile BugFan Mike for help with the ID.

One reason that slugs seem so foreign to us is that they lack familiar landmarks like legs, wings, and body segments.  So, what are you looking at when you’re looking at a slug?  They lead with two pairs of retractable, regenerate-able, sensory tentacles.  The top (dorsal) pair, which is used for sight and smell, has eyespots at the tips (slugs can see light and dark and blurry shapes but can’t focus on images), and the lower pair is used for smell, taste and touch and to move food to the mouth.  These four appendages can be aimed in different directions simultaneously, but the lower pair is often pointed downwards in order to pick up cues from the slug’s substrate.  The mouth, complete with rasping “teeth,” is on the underside of the head.

 

A saddle-shaped cover behind the tentacles, called the mantle, protects the slug’s innards; there’s an all-purpose opening on (almost always) the right side of the mantle called the pneumostome (one author calls it a “blowhole”), which has reproductive, excretory, and respiratory functions.  Beyond the mantle is the tail.  The muscular lower surface of a slug is the “foot;” its rhythmic undulation allows the slug to move, and it produces the infamous mucous/slime that keeps its body moist and “greases” its passage.

About that slime.  It’s a multipurpose substance that is both sticky and slippery, that aids in locomotion (some species use it as a bungee cord), that absorbs water, that protects slugs from bacteria and fungi, that leaves a trail for the amorous (and the carnivorous) to follow, and that discourages predators.  The BugLady found a tantalizing note about Hermann Lons, a German poet and malacologist (mollusc specialist) who discovered that slug slime tastes awful “in a particularly remarkable self-inflicted experiment” (about which she could find no further details).  Slug slime is also the strong yet flexible inspiration for researchers trying to develop a next-generation surgical adhesive.

 

Evaporation and slime production constantly rob slugs of their water reserves.  They can tolerate microclimates with a range of humidities as long as they can replenish liquid by eating and by absorbing water through their skin.  In hot, dry summer weather or when food is scarce, they will aestivate under debris or dirt, and they can fast for several months.

 

To place slugs within their proper taxonomic sphere, they are in the very diverse Phylum Mollusca (octopi and squid, scallops and oysters, snails and slugs), in the Class Gastropoda (“belly-foot” – snails and slugs), and in a land slug family named Agriolimacidae.

The GRAY FIELD/GARDEN SLUG (Derocerus reticulatum, aka Agriolimax reticulatum), one of about a dozen slug species in Wisconsin, is a European slug that’s described throughout both its historic and its more-recently-embraced ranges as a “synanthrope” – a species of plant or animal that lives in habitats modified by humans and that benefits from human association.  “Syn” means “with” and “anthropos” means “man,” and the term is applied equally to species we like (Golden retrievers) and species we don’t (Norway rats).  Across the Pond, it’s found in Western Europe and Africa; but it has hitchhiked (oh, so easily) pretty much around the world.  In North America, it’s found across southern Canada and the northern tier of states, plus a smattering of Central, Mid-Atlantic and Pacific Coast States.  It likes gardens, agricultural fields, roadsides, parks, and greenhouses.

 

Slugs are hermaphrodites, which means that they have both male and female reproductive organs – an individual can be the fertilizer or the fertilizee’ (and they can self-fertilize), and all can lay eggs.  In our area, Gray field slugs reproduce in late summer and early fall – Mom-Dad meets Dad-Mom in an elaborate dance that involves slime, a chase, and the waving of the sacrobelum.  Eggs (as many as 700 in all) are laid in small bunches under stones and leaves and in crevices as fall rains soften the soil.  They generally overwinter as eggs, hatch in spring, mature by late summer, and die not long after laying eggs.

 

Gray field slugs, notoriously, feed on the leaves and fruits of a wide range of agricultural and horticultural plantings and tree saplings, damaging leaves by rasping random holes in them.  They are also scavengers that eat dead, soft-bodied invertebrates like worms and other slugs.

 

One of the questions that the BugLady always asks when she’s researching is “What does it eat?” and the next question is “What eats it?”  Members of the ground beetle family Carabidae are important predators of Gray field slugs both here and abroad.  This beauty, a (coincidentally) European ground beetle that is now established here and is a fellow synanthrope, is a slug connoisseur https://bugguide.net/node/view/632699/bgimage (business end https://bugguide.net/node/view/1566065/bgimage).  The Gray field slug, however, can detect the odor of its ground beetle stalkers with those sensory tentacles, and chemicals mimicking ground beetle scents may have a future in crop protection.

 

When a ground beetle or other predator grabs a Gray field slug, the slug waves its tail back and forth and throws out lots of unpleasant, milky-colored slime (normally, its slime is clear).  The final trick in its playbook is to break off the tip of its tail and leave it in the mouth of its attacker as it scoots away.

 

Gray field slugs operate within a home range where they revisit food plants and home sites.  The BugLady’s slug notwithstanding, they tend to be nocturnal, and Wikipedia tells us that they can travel as far as 40 feet in one night.

 

Fun Slug Fact: when a slug ambulates across a copper surface, the copper reacts with chemicals in its slime and gives the slug a little shock.

 

Another Fun Slug Fact: the defensive slime produced by the Australian Red triangle slug is so sticky that it can glue a pursuing frog to a branch.  For days.

 

Final Fun Slug Fact: if you get slug slime on your person, it will be easier to remove if you let it dry and then rub it with a cloth than if you wash it with soap and water.

 

The BugLady looked around for a nice, uplifting literary quote about slugs.  She couldn’t find any.  They’re all allude to slugs’ perceived negative attributes, like this “We have descended into the garden and caught three hundred slugs.  How I love the mixture of the beautiful and the squalid in gardening.  It makes it so lifelike” (Evelyn Underhill); and this, “Bob Dylan impresses me about as much as …well, I was gonna say a slug but I like slugs” (Don Van Vleit); and this, “It seems to me the worst of all the plagues is the slug, the snail without a shell. He is beyond description repulsive, a mass of sooty, shapeless slime, and he devours everything” (Cecelia Thaxter).  Oblivious to the fact that slugs are, yes, perfect (and that possibly they find us repugnant).

 

Slugs in poetry?  The BugLady found this wonderful poem by George T. Watt; it’s dense, but lean into it and read it a few times http://www.scottishpoetrylibrary.org.uk/poem/slugs/ (Note – Ein Heldenleben – “A Hero’s Life,” is a work by Strauss).

 

About slugs, Watt goes on to say that “Slugs haes trevelled awa on its ain journey, ye maun tak it whaur it’ll gang.”

 

Words to live by.

 

Kate Redmond, The BugLady

 

Bug o’the Week – Bugs without Bios XIII

Salutations, BugFans,

 

Another celebration of (regrettably) anonymous bugs.  There are in the neighborhood of 100,000 insect species in North America, but not everyone has a biographer (note to self – it takes a lot longer to research the unsung species than the notorious ones).

HERAEUS PLEBEJUS (no common name): This pretty, little Dirt-Colored Seed Bug was a “life bug” for the BugLady – she knew it was in the “true bug” bunch, Hemiptera (which narrowed it down to 10,200 possibilities in North America) but she eventually stumbled across its identity and looked it up.  When the BugLady’s initial searches for species information draw a blank, she will back up to the insect’s genus and then to its family.  In this case, she struck out at pretty much every level – even the venerable An Introduction to the Study of Insects (Borrer and DeLong) in her home library had no info about Dirt-colored seed bugs.

 

So – it’s in the Dirt-colored Seed Bug family Rhyparochromidae (“rhyparos” means “dirt” and “chromus” means “colored”).  Rhyparochromidae used to be Rhyparochrominae, the largest and most diverse subfamily in the Seed bug family Lygaeidae (the family of the familiar milkweed bug).  Rhyparochrominae was elevated to family status about 30 years ago, and there’s been a lot of taxonomic fiddling ever since.  Most Rhyparochromids feed on seeds that they find on the ground, but some climb up plants for their supper, and there are a few blood-suckers in the crowd.  Some associate with ants, and a bunch of family members (but not today’s star), are able to stridulate (make noise by rubbing one body part against another).  Most have swollen-looking front legs armed with stiff spines that help them get a grip on seeds https://bugguide.net/node/view/742080/bgimage.  Some Rhyparochromids are economically important (in a negative way).

 

Heraeus plebejus is the most widespread of the four Heraeus species in North America; bugguide.net says that it occurs in “e. NA to AZ (QC-FL to IA-TX-AZ), Mex. / W. Indies,” and that it’s often found on sumac leaves.  Many of the seed bugs are pretty picky about what kind of seeds they eat, but the BugLady couldn’t find out anything about this species’ diet.  Insects foraging for seed on the ground probably aren’t choosy.  And that’s it.

ZENODOSUS SANGUINEUS (no common name) is a member of the Checkered beetle family Cleridae, which we have met before https://uwm.edu/field-station/checkered-beetle/.  The Clerids are a group of small, hairy, often-colorful, mostly predaceous beetles, many of whose larvae operate under the cover of tree bark, where they prey on the larvae of a variety of bark and cone-boring insects.  Adults feed on adult beetles that they find on flowers and other vegetation (though there are some outlier pollen feeders and scavengers).  Some species may prove to be effective biological controls of bark beetles.  American Beetles, Volume II tells us that “The higher classification of the Cleridae has undergone considerable categorical oscillations.”

Formerly known as Thanoclerus sanguineus, this little beetle is found from North Dakota to Arizona to North Carolina to Maritime Canada, under bark, in woody tunnels, and in galls and decaying fungi.  It is active but shy, and hides quickly when alarmed.  Adults overwinter under bark.  Other than that, this beetle’s internet presence is mostly on park and natural area biodiversity lists.  Glamour shot: https://bugguide.net/node/view/168452/bgimage.

EUPATORIUM/IRONWEED BORER MOTH (Carmenta bassiformis): Two groups of moths are called Clear-winged moths.  There are a few moths in the Sphinx moth family, including the wonderful Snowberry and Bumblebee clearwings that hover at bergamot and thistle flowers in summer (and lead the BugLady on a merry chase).  The other is the Clear-winged moth family Sesiidae, which we have visited before in the form of the squash borer moth https://uwm.edu/field-station/cornworms-and-hornworms-and-squash-borers/.  Their wings are “clear” due to an absence of scales https://bugguide.net/node/view/432923/bgimage. Many of these odd, little Sesiid moths are more waspy than mothy in appearance; they are bee and wasp mimics, a few even sporting yellow scales where bees would have pollen collecting equipment.  Some are agricultural pests and some are quite spectacular, with fancy anal tufts (in one species, the tuft is said to resemble the long, trailing, third set of legs of a wasp in flight) https://bugguide.net/node/view/484442/bgpagehttps://bugguide.net/node/view/367514/bgpagehttps://bugguide.net/node/view/1010752/bgimagehttps://bugguide.net/node/view/1542393/bgimage.

 

 

There were actually lots of hits when the BugLady Googled Eupatorium Borer Moth, but the sum total of their information was “larvae feed in the roots of Ironweed, and probably also Eupatorium (Joe-Pye-weed).”  Eupatorium moths are found in grasslands and edges east of the Great Plains.  Females advertise by emitting “Come hither” pheromones; they subsequently lay single eggs at the base of Joe-Pye or Ironweed plants, and the larvae bore into the roots and feed.  They overwinter as larvae and tunnel up into the stalks before pupating in spring.  Adults are nectar feeders, and neither stage is considered a pest. For nicer picture than the BugLady’s: https://bugguide.net/node/view/669993/bgimage.

 

Kate Redmond, The BugLady

Bug o’the Week – Azure Bluet

Howdy, BugFans,

 

Even in a group of damselflies that are called bluets, the Azure Bluet is an amazing color!

Bluets are damselflies in the Narrow-winged/Pond Damselfly family Coenagrionidae, which also includes the dancers, forktails and sprites. Most of Wisconsin’s 20 species of bluets are in the genus Enallagma (the American bluets), and except for two species that apparently didn’t get the memo (Orange and Vesper Bluets), males of most species have various amounts of blue and black on their thorax and abdomen (the front end of a Rainbow Bluet is so exciting that you don’t even notice the rear end).  For the sake of identification, bluets are divided visually into three groups.  If the abdomen is mainly blue, they’re in the “blue-type bluet” group; if it’s mostly black, they’re “black-type bluets; and if it’s about fifty-fifty, they’re “intermediate-type bluets.”  Bluets can be tricky to identify, and hand lens examination may be required.

 

Females are another story altogether; they’re greenish or tan far more often than blue, and when they are blue, they are less so than males.

 

 

Azure Bluets (Enallagma aspersum) are small (about 1 ¼”), black-type bluets.  In most bluet species the 8th and 9th segments, at the end of the abdomen, are blue, but the Azure Bluet also has blue on part of the 7thsegment.  Female Azure Bluets don’t have tan or green forms, and they are almost as blue as males, but instead of a solid blue tip, their abdomen has a pair of “spats” on both segments 8 and 9.  Males have large “eyespots” (postocular blue spots) on the back of their heads, and females’ eyespots are smaller.

Bugguide.net tells us that the Azure Bluet has a wide range – “Most of the Eastern United States, also a disjunct population in Montana. In Canada, reported from Ontario, Quebec, New Brunswick, and Nova Scotia.”  Within that range it’s found in a variety of (preferably fish-free) shallow lakes, ponds, swamps, bogs, and wetland edges with a lot of vegetation, but it’s pretty adaptable and will colonize gravel pits and man-made ponds.  Paulson, in Dragonflies and Damselflies of the East, says that it is “a good disperser, and often is one of the first Odonate species to colonize new aquatic habitat.”  It’s not widely distributed in Wisconsin; Bob DuBois, in the excellent Damselflies of the North Woods calls it “local in our region, but may be abundant once found.”  It’s a “Most Wanted” species in Wisconsin.

With a few minor twists and turns, the life history of an Azure Bluet mirrors that of any bluet.  Males hang out along the shore chasing rival males away from good egg-laying spots and waiting for females, which don’t approach the water until they are reproductively ready.  After mating https://bugguide.net/node/view/1259233/bgimage, they fly in tandem, looking for a suitable spot for her to oviposit.  The period between mating and ovipositing can be dicey – rival males are ready to pirate the lady – so the male retains his grip on the back of her head (contact guarding).

 

After mating, a typical female bluet perches on a favorable stem at the surface and backs down the plant stem, inserting eggs into it as she goes (see the accompanying photo of a pair of Marsh Bluets); if she submerges, the male releases her.  Female Azure Bluets take the bull by the horns, find a good piece of vegetation, and march down it headfirst to oviposit near the base of the plant.  She may descend more than a foot below the surface and stay under for 15 or 20 minutes (she turns gray while she’s down there, according to Paulson).  It is theorized that this will allow her eggs to survive the drop in water level caused by a summer drought.  The male waits for her above-decks and reclaims her, but she’s no longer interested.

Like other damselflies, the immatures (naiads) are aquatic.  Here’s a picture of a just-emerged Azure Bluet: https://bugguide.net/node/view/385530/bgimage.  They are carnivores as adults and naiads.

 

An Azure Bluet’s amazing color is all the more amazing because no blue pigment exists in bugs (or vertebrates, either).  Before the advent of eyes (about 600,000,000 years ago) color didn’t matter.  The world was far from black and white – animals get some of their pigments in the foods they eat, so there probably was color in that dark world – but its appearance was unappreciated.  It was only AE (After Eyes) that color mattered.  Which gave rise to one of the BugLady’s favorite quotes: “The eye of the trilobite tells us that the sun shone on the old beach where he lived; for there is nothing in Nature without a purpose, and when so complicated an organ was made to receive the light, there must have been light to enter it.”  (Louis Agassiz, Professor of Zoology, Harvard, 1870). 

For better or worse, color makes its wearer conspicuous, which can be desirable (courtship displays or warning coloration) or undesirable (red sea slug on green kelp – oops!).  Lots of colors come from dietary pigments – flamingoes are pink because of a carotenoids that they get from the tiny crustaceans they eat.  Blue is tough to glean from dietary pigments.  It’s a structural color, formed when light reflects off of tiny structures within the layers of the cuticle, an arrangement that bounces blue light back at the beholder.  The intensity of the blue can vary depending on the amount of light and the angle of the viewer.

To find out more about this arrangement, see http://www.npr.org/sections/health-shots/2014/11/12/347736896/how-animals-hacked-the-rainbow-and-got-stumped-on-blue.  For a deeper, more technical dive, try this one http://what-when-how.com/insects/coloration-insects/.

 

Up until the third week of January, we were having “Winter Lite” here in God’s Country.  Since then we’ve had snow, more snow, a visit from the Polar Vortex, ice, and even more snow.  We haven’t had a long winter, but at the risk of sounding like wimps, we’re ready to start that slow climb toward spring (the BugLady heard a Cardinal singing the other day).  In that spirit, she offers this quote from Canadian broadcaster, reporter, and writer Peter Gzowski: “We need spring. We need it desperately, and, usually, we need it before God is willing to give it to us.”

 

Kate Redmond, The BugLady

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

 

Bug o’the Week – Speed-dating the Spiders – Variegated Spider

Greetings, BugFans,

 

The BugLady found this striking spider at Riveredge Nature Center one early summer day.  What it lacks in size (it’s less than ½”), it surely makes up for in beauty (thanks for the ID, BugFan Mike).

 

There’s not a lot of information out there about the Variegated spider (Sergiolus capulatus).  Only one source gave it a common name, but most of the other species in its family don’t have common names, either.  It is found across the eastern US from the Atlantic to the Great Plains, usually on the ground, under leaf litter, and in grasslands, open areas, and in sunny spots in deciduous woods.  It favors dry habitats over moist ones.

 

Except for a few genera, its family members tend to be drab, and all of them sport conspicuous twin spinnerets at the end of their abdomen.  Scientists speculate that the Variegated spider’s color pattern mimics that of some species of velvet ants that can be found in the same neighborhoods (a velvet ant picture is included here).  Velvet ants (family Mutillidae) are actually flightless, female wasps whose stingers pack quite a wallop.  Nobody messes with velvet ants.

Like crab spiders and jumping spiders, Variegated spiders do not spin an elaborate trap web; they stalk their prey on foot (more about that in a sec).  Most sources call them nocturnal, but a few disagreed, calling them diurnal (daytime) hunters.  In any case, they spend their “down” time, and cooler days and nights, in a snug, silk-lined retreat.

 

The BugLady started finding good stuff (most of the good stuff is silk-related) when she researched the family rather than the species.  Variegated spiders are in the Ground spider family Gnaphosidae, aka the Flat-bellied or Stealthy ground spiders (one source said that Gnaphosidae is Greek for “living in the dark”).  There are about 2,000 species in the family; just over 300 of those are found in North America, where there are more species in the west than in the east.

 

To back review, spiders are capable of making different kinds of silk for use in different situations, like egg cases and trap webs and balloons and shelters and safety nets and more https://uwm.edu/field-station/the-wonders-of-webs-i-spider-silk/.  Not all spiders have or need all the options, and producing silk is “expensive,” energy-wise.

 

Ground/Gnaphosid spiders often go after prey that is as large as or larger than they are, like ants, and their fellow spiders (araneophagy).  It’s dangerous – a predator can get hurt in a wrestling match, and some prey may be venomous – but ground spiders have developed an impressive strategy for subduing struggling prey.  It’s called a “swathing attack.”

 

A hunting Gnaphosid spider approaches its prey and typically tries to make some tactile contact with it.  That touch allows it to gauge whether or not it will be able to subdue its food without a fight (by wrapping it in a “leg basket”).  If it does need to deploy silk, it targets the prey’s legs and mouth with thick, sticky globs of silk.  In an article in the Journal of Experimental Biology, researchers Wolff, Řezáč, Krejčí, and Gorb called it “hunting with sticky tape” (http://jeb.biologists.org/content/220/12/2250).

 

They point out that food-getting drives many adaptations.  Some animals avoid “risky prey,” but Gnaphosids have developed a modified spinning apparatus that produces an especially gluey silk that that is both stretchy and strong.  It allows them to immobilize prey very effectively, but at a cost.  When foraging spiders like Jumping spiders or Crab spiders launch themselves at their prey, they first attach a bit of web to their substrate; if their lunge takes them over the edge of a leaf, they’ve got an anchor/dragline.  Dragline silk also functions in navigation, communication, trap-web construction, and egg sac suspension.  Gnaphosid spiders aren’t able to make dragline silk, but it doesn’t seem to have bothered them much – Gnaphosidae is the 7th-largest spider family, and its members are especially dominant in dry, open areas.

 

Ground spiders use a different kind of thread to make a sac for their eggs, and females stand guard until the eggs hatch, like the closely-related Clubionid spiders.  They also weave silk into mesh-like shelters that they stay in when they’re not hunting.

 

Here are a couple of neat spider sites: https://www.emporia.edu/ksn/v55-december2007/ and https://fieldguides.fieldmuseum.org/sites/default/files/rapid-color-guides-pdfs/390_1.pdf.

 

Kate Redmond, The BugLady

 

Fostering the Flowers of Tomorrow: Native Orchid Restoration at Riveredge

If a canary is a health gauge for air quality in a coal mine, then one might consider our native temperate orchids a gauge for the health of our native plant communities.

Judy Larsen, spouse of the first Riveredge employee Andy Larsen, remarked that when they arrived to Riveredge 50 years ago, she observed a healthy orchid population, including a prominent grouping of Yellow Lady’s Slipper along the Milwaukee River. Yellow Lady’s Slipper has since been extirpated. White-tailed Deer are known to prefer this species, and the large herd size could be part of the reason behind its disappearance. Today, we have three known orchids on the property and are working to support these remaining species.

By researching our ‘canaries’ we hope to better understand the variables that individual orchid species need for success. We aren’t doing this alone but rather through collaborations with local partners so we may ultimately restore them to areas where they once thrived.

Through a Wisconsin Coastal Management grant, we have partnered with Sheboygan County, Stantec, The Chicago Botanic Garden, and the Minnesota Landscape Arboretum to setup long-term monitoring locations in coastal counties, propagate hundreds of individuals, and raise said individuals in a shadehouse until they are vigorous enough for out-planting. Partners outside of this two-year grant include The Smithsonian Institute, North American Orchid Conservation Center, The Ridges Sanctuary, and Illinois College.  

Certain fungal communities work with orchid species through symbiotic relationships. In this way, the fungus is a surrogate root system for germinating seeds. Recognizing the importance of these relationships when returning a species to the landscape, our partner Illinois College is isolating unique fungal species associated with native orchids.

“It’s wonderful to see so many passionate researchers working together for the good of these species,” said Land Manger Matt Smith, “Through collaboration we can not only ensure the health of these species on our land, but in our region as well.”

In spring 2019, we will construct an Orchid Shade House, a nursery to raise native orchid seedlings for our immediate acreage and other natural areas that are suitable for temperate orchid reintroduction. We’re seeking the help of Citizen Science volunteers to document the health of orchid populations across our study sites, as well as anyone who has an interest in growing plants in the shade house. Through this project, you can help us discover the complex interconnected lives of Wisconsin plants and foster flowers that will be found by the next generation of explorers.

Bug o’the Week – Horned Passalus (Bess) Beetle

Howdy, BugFans,

 

The BugLady has been wanting to do an episode about Bess beetles for a long time, but she didn’t have a picture of one (many thanks to BugFans Tom and Joe for sharing).  Why Bess beetles?  Because they exhibit what’s called “pre-social behavior,” and they vocalize like crazy, and they have lots of names, and then there’s the phoresy.  The “Insects of Duke University” website calls them “one of the most delightful discoveries one can make upon overturning logs.”

Its common names pertain to its appearance and its voice.  Bess beetle seems to come from the Old English “buss” (“kiss”), a reference to a kissy sound the beetle makes, Peg beetle because when it’s sticking its head out of a log, it looks like a carpenter’s peg, and Patent leather beetle is self-explanatory.  Horn beetle probably refers to the horn on its face https://bugguide.net/node/view/270651/bgimage, although one author speculated that the beetle is shiny, like horn material.  The species has also gone through lots of scientific names since it was described by Linnaeus in 1764 (some of them, more than once), having been placed in five different genera and been given a half-dozen species names before arriving at Odontotaenius disjunctus.

Horned Passalus beetles are in the Bess beetle family Passalidae – a family with about 500 species of mostly New World, mostly tropical beetles.  There are two members of the genus Odontotaenius north of Mexico; one is limited to a single county in Florida, and the other is found in rotten logs and stumps in deciduous woodlands over much of North America east of the Great Plains.  But not in Wisconsin.  According to Kriska and Young in “An annotated Checklist of Wisconsin Scarabaeoidea (Coleoptera),” “Rauterberg (1889) reported this species to be widely encountered in Wisconsin, however, he provided no further locality data, and no Wisconsin specimens have been found. It is possible that this species has been extirpated from Wisconsin due to the loss of mature, old growth forests with downed timber of moderate to large diameter in the southern half of Wisconsin.

 

Unlike the BugLady’s usual fare, this beetle is far from microscopic – measuring about 1 ½” long, with hefty mandibles and an impressive girth (females are the same length as males but tend to be broader across the thorax).

Horned Passalus beetles, like many other Passalids, live most of their lives within the confines of a hunk of rotting wood (they are especially fond of oak and hickory), though they will venture out to crawl around on the log by day or in search of a new home.  Their life in the log is somewhat climate-controlled and predator-free, and they will defend it from intruders.  They aren’t social in the extreme manner of honey bees and ants, but they are “presocial,” with several generations overlapping sociably “under one roof.”  They use their impressive mandibles to tunnel into wood and to eat it, and they raise their young in it, protecting them and tending to their needs (because the larvae are helpless), and the larvae eventually pupate in the tunnels.  The beetles will continue to use the same site for generations, as long as the wood holds up; a small hunk of wood will hold one family, but a large log could support several.  HPBs are not a danger to homes or decks, but are effective forest recyclers.

Males vie for territory/sections of the log and for females, using their horns to flip their rivals over.  Although open-air nuptial flights have been observed, HPBs mostly mate in the tunnels/galleries, and pairs remain monogamous throughout the summer.  The female lays 25 to 30 eggs (large eggs, which the adults pick up and carry around to good locations in the galleries), and she nestles her eggs into cozy nests of frass (bug poop).  Larvae are fed by both Mom and Dad on a diet of pre-chewed wood pulp mixed with “parental secretions” and frass, and the adults construct and maintain pupal cells for their larvae when the time comes.  Depending on climate and nutrition, the larval lifespan lasts from three to twelve months and adults live about a year.

 

Injured larvae may be cannibalized, and larvae may also be eaten by unmated HPB adults that attempt to invade their log home.

 

Newly formed pupae are a beautiful, pearlescent color that gets duller with time https://bugguide.net/node/view/314646/bgimage, and the newly-emerged adults (tenerals), are a rich red https://bugguide.net/node/view/3327/bgimage for a while before settling into their adult coloration.  Young adults overwinter in the family tunnels and disperse the next spring, but while they’re in the parental log, they may help to care for new siblings.  Scroll down to see pictures of stages, and be sure to listen to the audio tape at the bottom – http://entnemdept.ufl.edu/creatures/misc/beetles/horned_passalus.htm (or by-pass the pictures and go directly to http://entnemdept.ufl.edu/creatures/misc/beetles/horned_passalus15.mp3.

As they tunnel through/eat the wood, HPBs leave behind a trail of frass.  The frass is acted on by fungi and bacteria present in the woody galleries, and then it is re-ingested by the adults.  This (and the feeding of frass to the larvae) reinforces the rich microflora that allow the beetle’s gut to digest cellulose.

 

Seventeen different “vocal” communications have been observed in HPBs – a repertory that exceeds that of many vertebrates.  Researchers Reyes-Castillo and Jarman call this “the most elaborate system of sound communication known for any arthropod.”  Adults make sound by stridulation (friction), using structures located under their elytra (hard wing covers).  They rub rows of spines on their folded flying wings against the top of the abdomen; larvae “vocalize” by rubbing legs together.

 

Some sounds are defensive (here’s an HPB reacting to a person who insists on poking it with a stick https://www.youtube.com/watch?v=O1KonQZdSAU) and some sounds are social – used in courtship, larval management, or other colony-related purposes.  Buchler, Wright, and Brown observed that crows were distinctly put off by the noise, taking longer to attack, kill, and eat vocal HPB larvae or adults.

 

HPBs are almost never alone – many go through life with a variety of tiny mites attached to their exoskeleton.  Most of these mite species are not feeding on the beetles, simply using them as a taxi service to get to more favorable habitats (phoresy), because tiny mites have even tinier legs.  One source suggests that Passalids are susceptible to the mites because Passalids are big, dumb, non-predators (the BugLady has no comment about that).  Others say that mites like the same kinds of logs that Passalids like, that the beetles occupy a log long-term, not just seasonally, so there’s lots of time for interaction, and that mites that are thrown together on the beetle’s exoskeleton may use the opportunity to do some courting.  If all that the mites wanted was a ride, then any bark-dwelling critter would do, but they favor Passalids.  Mites find their rides by chemical cues, and they attach in nooks and crannies where they won’t get scraped off in the tunnels https://bugguide.net/node/view/169823.  The HPB has 16 species of mites that use it exclusively.

Bess beetle with mites

Fun HPB Fact #1 – Although they are fully capable of flight, these beetles prefer to hoof it (slowly) across their landscapes most of the time.

 

Fun HBP fact #2 – HPBs are very strong – studies show that they are able to pull 50 times their own weight, and stress can make them even stronger.  Females pull harder (their greater thoracic girth conceals a greater muscle mass), which suggests that they may do the lion’s share of excavating and pushing through tight spaces.  Interestingly, beetles with the longest horns were strongest.

 

Fun HPB Fact #3 – Because they are big and totally non-aggressive and easy to take care of, HPBs are popular as pets, in insect displays, and for lab work.

 

Kate Redmond, The BugLady

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

 

Bug o’the Week – Short-winged Bunchgrass Locust Revisited

Greetings, BugFans,

 

Back in the summer of 2009, the BugLady found a spectacular grasshopper in the UWM Field Station prairie (she waded in, her desire to photograph it outweighing apprehension caused by the number of chiggers that live in that particular bit of grassland).  It was a Short-winged Bunchgrass Locust/Grasshopper (Pseudopomala brachyptera) (brachyptera means “short-winged”), also known as the Short-winged Toothpick Grasshopper, and she issued a special Bonus Bug (an “in-between episode”) to celebrate it.  This is a revision of that post, with some new information.

SWBGs are located in the Short-horned Grasshopper family, Acrididae, which BugFans have visited before in the form of the Meadow, Pine-tree spur-throated, Green-legged, and Green striped grasshoppers, and the Red-legged grasshopper/locust and Carolina locust.  There are about 8,000 species in the family worldwide, 620 in North America, and some species can occur in plague-sized quantities.  They’re in the Slant-faced grasshopper subfamily Gomphocerinae and in a group called Mermiria – the Toothpick grasshoppers.

The last time the BugLady wrote about grasshoppers/locusts (whose names, at least in the common usage, are often interchangeable) a knowledgeable BugFan sent her an explanation of the distinctions, which the BugLady “saved” but which (apologies) is nowhere to be found.  Here’s how Wyoming Extension Entomologist Vsevolo Latchininsky explains it in an article in the Encyclopedia of Animal Behavior (2010).  “All locusts are grasshoppers but not all grasshoppers are locusts.”  Locusts, he continues, are “short-horned grasshoppers (Orthoptera: Acrididae), distinguished by their density-dependent behavioral, physiological, and phenotypic polymorphism.”  That sentence takes a little unpacking.

 

Polymorphism refers to an organism that has several forms, like Mallard Ducks, with showy males and camouflaged females; and phenotypic refers to appearance.  When they occur in “normal” numbers, these grasshoppers are just grasshoppers, hopping around, solitary except when breeding.  When they have a population boom, usually in response favorable weather and a bumper crop of their favorite food, a very small number of species may respond by producing a generation that is gregarious, which can lead to swarming (density-dependent behavioral polymorphism), and that looks different because of changes in color or body structure (phenotypic polymorphism), and then we call them locusts.

Along with that distinctive face (http://www.montana.edu/yellowstoneinsects/orthoptera/pseudopomala_brachyptera.html, Slant-faced grasshoppers tend to have clear-to-yellowish/bluish hind wings that may be darker on the trailing edge, and they have a raspy area/file on the inner side of the hind femur that they rub against a similarly raspy area on the front wing to make sound (stridulate).  Males “sing” to females during courtship.  Their head shape causes some people to mistake them for walking sticks, and like walkingsticks, their slim legginess allows them blend into a grassy thicket.  The technical term for their wild-looking antennae is ensiform(from the Latin enis – sword, related to the Sanskrit asi, also meaning sword).

 

If, like the BugLady, you appreciate old scientific illustrations, see this 1902 drawing – https://www.flickr.com/photos/internetarchivebookimages/19178012629/.

 

SWBGs display sexual dimorphism – males are slightly smaller and darker in color than females and have longer wings (females’ wings are usually less than half the length of their abdomen).

Mermirids tend to be found in areas with thick, damp grass; SWBGs have a preference for tallgrass prairies (they’re sometimes described as an insect of prairie remnants), but they’re also found on poor soils, in sand prairies, and along forest and stream and weedy road edges (long stretches of roadside grasses provide an avenue for SWBGs and other insects to disperse along).  Their range stretches from north Texas to Idaho to British Columbia on the west, through the Great Plains and southern Canada, and east through the Great Lakes states to New England, and they’re mostly present in the southern half of Wisconsin.  SWBG populations tend to be “local” – found in small pockets over large areas, and both their numbers and their range may be increasing with recent droughts (but they’re not numerous enough to have an economic impact).

 

Their short wings suggest that migration is unlikely, but they are terrific hoppers, and they like to play peek-a-boo from the opposite side of a grass stem.

There’s not a huge amount of information out there about the population, reproduction, and daily schedule of SWBGs (a testimony to the low profile they keep).  Eggs are laid in late summer, and they probably overwinter in the egg stage; adults hop around throughout summer, not far from the areas they occupied as nymphs.  SWBGs feed on a variety of grasses (including Kentucky bluegrass) and a few sedges.

 

Thanks to BugFan Dennis for two corrections of last week’s episode about the Rusty-patched bumble bee.  This bee is listed as an Endangered species in Wisconsin (insufficient scholarship on the BugLady’s part), and the bumble bee that had the unfortunate encounter with the ambush bug is likely a Red-belted rather than a Brown-belted bumble bee.  Thanks, Dennis.

 

It takes a village.

 

Kate Redmond, The BugLady

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