Author: rbuchholz

Howdy, BugFans,

The BugLady’s #3 child nailed it years ago when she proclaimed her mother an “Essoterrorist” – someone with a fondness for squirreling away obscure facts.  Here are some of the Bug Facts that she’s come across while looking for something else.

Zika among us 

As overzealous communities in the path of the Zika virus consider “nuking the wetlands,” remember that Zika-carrying mosquitoes don’t rough it out in the wild, they are suburban-urban-dwellers.  “There are over 3,000 mosquito species worldwide, but only a couple of hundred are important medically,” says Janet McAllister, Ph.D. of the CDC. “That’s because most species of mosquito don’t even bite humans — some prefer other animals like amphibians and reptiles.”  See five common mosquito myths at http://www.huffingtonpost.com/2013/05/26/mosquito-myths-misconceptions-insects-diseases_n_3328497.html.  The average mosquito consumes 1/1,000,000 gallon per bite (it would take 1,129,000 bites to drain the blood from the average human) http://www.caprince.com/turtle/Documents/mos3.pdf.

Insects in the Art Gallery

Albrecht Durer, a 15^th/16^th century German artist whom the BugLady admires, produced an engraving at the end of the 15^th century that is variously called The Holy Family with the Dragonfly, The Holy Family with the Mayfly, The Holy Family with the Locust, and The Holy Family with the Butterfly.  Wikipedia tells us that “In the lower right corner is an insect frequently identified as a dragonfly. However, Dürer may have intended it as a butterfly, a creature whose dramatically transformative life-cycle makes it a perfect symbol of resurrection and redemption.” Click to magnify the picture and make a guess: https://upload.wikimedia.org/wikipedia/commons/8/89/The_Holy_Family_with_the_Dragonfly_by_Albrecht_Durer.jpg.

One-liner

Another gem from Wikipedia: “Arthropods are so versatile that they have been compared to Swiss Army knives.”

How many???

From the Smithsonian:

• Insects probably have the largest biomass of the terrestrial animals. At any time, it is estimated that there are some 10 quintillion (10,000,000,000,000,000,000) individual insects alive.
• In the world, some 900,000 different kinds of living insects are known. 91,000 species have been described in the US, but there may be 73,000 more species waiting to be discovered/described here.
• Someone did the math on soil samples taken to a depth of 5” in plots in North Carolina and projected that the soil contained 124 million animals per acre.  Mites and springtails ruled, with 90 million and 28 million each.  4 ½ million were “other insects.”  A similar study in Pennsylvania suggested 425 million animals per acre.
• Assuming no mortality of their offspring or their offspring’s’ offspring’s offspring, a single pair of house flies might be patriarch and matriarch to 190 quintillion young in five months.
• There are 200,000,000 individual insects for every man, woman and child on the planet. See http://www.si.edu/Encyclopedia_SI/nmnh/buginfo/bugnos.htm for more.

But – who’s counting?

In an article in Science 2 magazine in 2010, author Robert M. May considers how to answer an extraterrestrial’s obvious question “How many distinct life forms—species—does your planet have?” But, he notes, look who’s doing the counting.  He tells us that “we began systematically naming species just a little over two centuries ago, and that our labor force is inefficiently distributed: about one-third of taxonomists work on vertebrates (at most 1% of the total number of species), one-third on plants (around 10%), and the remaining one-third on invertebrates (comprising at least 90%). Furthermore, a lack of broad, synoptic databases and problems with synonyms—the same species cataloged differently in different collections—means that we are uncertain, by around 10%, of how many distinct species we actually have named and recorded.”  So, what’s the grand total?  Read all about it at https://www.researchgate.net/publication/44902098_Tropical_Arthropod_Species_More_or_Less.

A spoiler alert from May: “Overall, these conclusions imply that around two-thirds of all arthropod species still await discovery and description. In part, this sorry state of affairs reflects inefficient distribution of taxonomic attention, which is disproportionately directed to the more appealing furry and feathery vertebrates. It also often reflects a tendency for funding agencies, in the United Kingdom and elsewhere, to view research on basic systematics and taxonomy as insufficiently sexy …..  My guess is that the hypothetical aliens would take a dim view of all this.”

Plutarch may have gotten this wrong 

About dung beetles, sacred to the Egyptians, Plutarch wrote: “The race of beetles has no female, but all the males eject their sperm into a round pellet of material which they roll up by pushing it from the opposite side, just as the sun seems to turn the heavens in the direction opposite to its own course, which is from west to east.”

Not just another pretty face

The BugLady crowds her front porch with geraniums each summer and brings them all inside (usually at midnight, with a heavy freeze descending) and then abuses them all winter by forgetting to water them (her picture is probably posted near the cash register at area garden stores – Do Not Sell to.…).  Now she appreciates them even more.  Turns out that chemicals in the petals (maybe the leaves, too) paralyze herbivores like Japanese beetles for a few hours, during which time they are more vulnerable to predators http://blog.extension.uconn.edu/2015/03/02/plant-defenses-against-insects/.

Survey Says 

Researchers drove two road routes (one forested, one urban) through the Northeastern part of the continent to test an old insect censusing method made new – they substituted sticky tape on the front bumper for the time-honored radiator grill.  In analyzing the 400,000 bits of DNA found adhering to the tape, they identified up to 2,000 insect species and many (many) species of bacteria, as well as other microbes, plant bits, and non-insect animals (including human).  It’s called metagenomics – the study of DNA recovered from environmental samples, and needless to say, the database/technology for this kind of sampling is being built on the go.  For a very scientific explanation: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2775585/; for a slightly less scientific explanation: https://mentalindigestion.net/2009/11/20/windshield-splatter-analysis/.

Who Knew??

Scientists Worthen and Hart, who were studying the ability of some dragon/damselflies to reject parasitic mites more effectively than others, made these observations (Hydraphantidae Limnocaridae, and Arrenuridae are mite families): Hydraphantids and limnocarids have terrestrial larvae that either leap from the surface of the water to infect mature odonates in flight or colonize odonates perching along the shoreline [emphasis, the BugLady, who has no visual of a mite leaping]. Arrenurids have aquatic larvae; most species colonize odonate naiads and begin to feed on the emerging adult at ecdysis, but some species colonize mature odonates returning to water to mate or oviposithttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4864583/.  Mites like crane flies like the one pictured here, too, many of whose larvae are aquatic.

New Age hornets

Oriental hornets (Vespa orientalis) generally build their communal nests underground, excavating bits of soil and building cells for eggs and larvae, (they may opt for an above-ground, paper nest).  Either way, it’s dark inside – how’s a gal supposed to tell which way’s up?

It turns out that they orient using gravity, but they also embed (using saliva) a tiny “keystone” crystal in the “ceiling” of each cell. “The resulting network of crystals, researchers say, may serve the same purpose as a surveyor’s level, helping the insects maintain symmetry and balance when building their precisely oriented and uniform nests” https://www.scientificamerican.com/article/keystone-like-crystals-ma/.

Vibrations in the nest cause the crystals to vibrate and allow the hornets to gather information.  Says John Pickrell in “Mystery in a Hornet’s Nest,” “When the hornets tap the hive surface with their feet, the crystal does not dance in the same way as the rest of the comb, enabling the insects to glean information about the orientation of their nest.”

The tiny, magnetic crystals contain titanium, oxygen, iron, and carbon – all elements that are readily available in the hornet’s environment – and in their bodies; there is speculation that rather than hunting for them, the hornets manufacture the crystals themselves!  Oriental hornets are multitalented; http://news.nationalgeographic.com/news/2010/12/101221-solar-power-hornet-science-animals/.

And that’s how it is – always.

“Each observation, however, has raised more questions than it answers, so the sum of my watching has caused me to grow in ignorance, not in knowledge.”  Sue Hubbell, chapter on Camel crickets in Broadsides from the Other Orders. 

The BugLady

Howdy, BugFans,

Like other media in the period between Christmas and New Year’s, this is a rerun, though it is slightly enhanced from its original appearance eight years ago.  But – the BugLady promises that it does not contain elves, reindeer, Grinches, chipmunks, snowmen, or Jimmy Stewart.

For years, the BugLady misidentified this leggy, inch-long beetle as a Bombardier beetle (genus Brachinus), but having finally managed a decent photo of one, she was able to identify it as a False bombardier beetle (genus Galerita), and she learned the secret handshake – Brachinus have red heads and Galerita have black heads.  According to bugguide.net, Galerita comes from the Latin galeritus, meaning “wearing a fur hat.”

Continue reading “Bug o’the Week – False Bombardier Beetle Redux”

Greetings of the Season, BugFans

“The Twelve Days of Christmas” is an English carol that was probably borrowed from the French and that was originally an acapella chant/call-and-response/children’s memory game.  There’s an alternative explanation about the various lords, rings, etc. being Christian code words for catechism during a time of religious repression, which seems a bit like playing Beatles songs backwards).  It first appeared in writing in 1780, and there were (and still are) many variations of it, though the words were more-or-less standardized when an official melody was finally written for it in 1909 (and the insect verse was, alas, omitted).

See https://en.wikipedia.org/wiki/The_Twelve_Days_of_Christmas_(song) so you can hold your own in Holiday Trivia at parties (I’ll take Christmas Songs for $300, Alex).  With apologies to all those Lords a’ Leaping, it’s time once again to celebrate a year of bugs with this baker’s dozen collection of the beautiful, the odd, and the mysterious.  Gifts.  Right under our noses.  All the time.

Continue reading “Bug o’the Week – The 13 Bugs of Christmas”

Greetings, BugFans,

Ichneumons – what an amazing bunch!  First-off, there are a whole lot of them.  The numbers are a little soft, but the 5,000 species listed for North America might eventually be joined by another 3,000 that are awaiting discovery.  Worldwide, there are an estimated 60,000 species, and that could grow as high as 100,000 – even low-balling it, they are considered to be the largest single family of animals (not just insects – animals) in the world.  Second, while some Ichneumons are very small, many are large and beautiful insects.

Continue reading “Bug o’the Week – Ichneumon Centrator Wasp”

Hey, BugFans,

The BugLady has expressed her affection for stink bugs before https://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/stinkbugsrevisited.cfm (check out the story about how some stink bugs can escape from a spider web).  To her delight, they were everywhere this summer.

Stink bugs (family Pentatomidae) (from “penta” – five and “tomos” – section, a reference to the number of segments in their antennae) are a mixed group.  As true bugs, they have piercing-sucking mouthparts in the form of a tube that is inserted into their food source, through which digestive juices are injected, and through which the resultant pre-digested tissue is extracted.  The family contains herbivores, including a number of agricultural pests; carnivores, some of which are used as biological controls on other insects; and a few that start their lives as plant feeders but switch to animals early on.  A comment in bugguide.net suggests that the carnivorous stinkbugs have broader “beaks” than the herbivores do; the thin beak of a green stink bug can be seen in an attached picture, and the mouthparts of a Podisus can be seen among a nice family album of pictures at the Great Backyard Arthropod Project at http://somethingscrawlinginmyhair.com/2014/05/10/predatory-stink-bugs-reared-from-eggs-webworm-destroyers/. There are about 250 species in North America and 5,000 worldwide. 

Stink bugs?  Because when they are fussed, they release what Kaufman and Eaton, in the Field Guide to Insects of North America call “aromatic compounds sure to repel all but the most desperate predators.”  Researchers Krall, Bartelt, Lewis, and Whitman published a study on the twice-stabbed stink bug, featured below, explaining how this smelly defense works for TSSBs (a story that is undoubtedly similar for other stink bugs).  Adult TSSBs have two glands on the top of their thorax through which they can emit a liquid which is a combination of 11 “volatile compounds;” the nymphs have three pairs of similar glands on their abdomen.  The liquid is released as droplets, not as a spray.  Some of the elements in this cocktail are poisonous; others are irritating, and still others are repellant.  The liquid emerges onto roughened areas of the cuticle where it sits as a droplet but does not spread, and it can be reabsorbed after a few seconds.  The exception comes when the substance is released on the bug’s leg, and then it spreads out and covers the leg’s smooth surface.

It took some poking and prodding by the scientists to make a bug initiate a release of chemicals – producing the stuff is, after all, an energy expensive exercise, so using it must be worth the insect’s while – but as the bugs got more agitated, it was easier to get them to react.  Turns out that the muscles that control these emissions are pretty sophisticated, and the release can be targeted – poking the right side of the bug caused release of secretions on its right side, but brushing the head brought a two-sided reaction.  Gentle stimuli provoked small droplets, and rough handling produced more.

Some predators are pretty much flummoxed by all this.  Starlings sampled one bug and spit it out immediately, apparently put off by the instant “flavor burst.” The clever bug can time the chemical surprise to coincide with the moment it lands in a predator’s mouth (a time of higher danger rather than mild danger), which often results in its release, alive.  Killdeers ate one, but then refused seconds.  Anole lizards ate them a few times but then rejected them, implying the build-up of a toxin.  American Robins were pragmatists; despite the unpleasant experience, they continued to eat TSSBs if nothing else was offered.  Predators displayed aversion behaviors when the next TSSBs were served up.

The authors considered the idea that the chemicals acted as aggregation pheromones, since males and females produce similar chemicals and TSSBs are often seen in groups (often flagrante delicto) or possibly as alarm pheromones (since the odor of the researchers’ stinky fingers caused TSSB stampedes on flowers.  The bug’s aposematic (warning) coloration tells us that something is going on.

Anyway, one sunny morning at the end of May, as she was hanging wash on the line, the BugLady spied these stink bugs in the tall grass nearby (imagine – after almost 40 years at this place, she is still finding new bugs!).  They turned out to be TWICE-STABBED/TWO-SPOTTED STINK BUGS, named for the two red spots on their scutellum, the triangular patch on the thorax between the wings, and also known regionally as Wee Harlequin bugs.  They were formerly, and more intuitively, known as Cosmopepla bimaculata but were renamed Cosmopepla lintneriana in 1909 to honor Joseph Lintner, an agricultural entomologist who held the position of New York State Entomologist from 1881 to 1898.  There’s another stinkbug, Perillus bioculatus, that shares the common name Two-spotted stink bug, and there’s a Twice-stabbed lady beetle, too.

TSSBs can be found across much of North America and south into Mexico; they feed on a bunch of different plants including the seeds of mints (especially hedge nettle, Stachys palustris), some composites, asparagus, and oats.  They’re about a quarter of an inch long.  They’re pretty hardy, overwintering as adults (sometimes as late-stage nymphs), and hiking around soon after the snow melts in spring.

Eggs are laid on the undersides of leaves, about 12 hours after copulation (they remain joined for about 24 hours).  Sometimes a female will retain fertilized eggs in her body for another 24 hours or longer, and these eggs inevitably hatch more quickly.  Nymphs release themselves from their eggs using a tough, triangular “egg buster” on their heads.  For a shot of a nymph and a close up of an adult, see http://bugguide.net/node/view/359885/bgimage and http://bugguide.net/node/view/1163942/bgimage.

The second stinkbug du jour is PODISUS PLACIDUS (probably).  Members of the genus Podisus are sometimes called the Spined soldier bugs (there’s a spine on each side of an adult’s thorax), and they are found in forests and fields across the northern two-thirds of the US and into Canada.  The adults are medium-brown, pitted and speckled, and are in the three-eighths-of-an-inch range http://bugguide.net/node/view/548271/bgimage.

These are meat-eaters http://bugguide.net/node/view/548270/bgimage.  Some Podisus species are marketed and exported for pest control, and cannibalism is not unknown among the nymphs.

Other members of the genus feed on cabbage worms, corn borers, corn earworms, gypsy moth caterpillars, webworms, and Colorado potato beetles, among other notorious species.  The saliva of one species was studied and found to have contain chemicals that both paralyzed and killed its prey.  Podisus placidus searches for sawfly larvae and Lepidoptera caterpillars, especially Eastern tent caterpillars (and will enter their tents to nab them), and forest tent caterpillars (which, despite their name, don’t spin tents).  For a shot of a Podisus nymph that is truly out on a limb, see http://bugguide.net/node/view/43333/bgimage.

Kate Redmond, The BugLady

Bug of the Week archives:
http://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/

Hey, BugFans,

One of the last bugs to grace the BugLady’s porch light in autumn is the brown lacewing (she sees its jewel-like cousin, the green lacewing, in mid-to-late summer).  Because of this year’s long, mild fall, brown lacewings straggled on into early November.

Brown lacewings belong to the order Neuroptera (“nerve-winged”).  The order seems to be under constant review by taxonomists, and its inhabitants have been shuffled and re-dealt into suborders under the superorder Neuropterida, which embraces lacewings as well as oddballs like mantidflies http://bugguide.net/node/view/324938/bgpage (yes, these occur in Wisconsin), spongillaflies http://bugguide.net/node/view/432609/bgpage (so do these), antlions http://bugguide.net/node/view/288349/bgpage (and these), and owlflies http://bugguide.net/node/view/824399/bgpage.  Snakeflies and the more familiar alderflies, fishflies, and dobsonflies (hellgrammites) have been dealt out and given their own orders but are sometimes included in discussions about the Neuropterida.  Neuropterans are generally soft-bodied, weak-flying insects (they’ve been likened to drab, awkward damselflies) that are active in the dusk/dark and that have complete metamorphosis (egg-larva-pupa-adult).  Brown lacewings are in the family Hemerobiidae, with about 500 species worldwide (60 in the US).

Adult brown lacewings have four-wings and are a half-inch-long(ish), with light brown wings, often patterned, and they are less conspicuous – and hairier – than green lacewings (family Chrysopidae).  They have chewing mouthparts and conspicuous eyes, and they somewhat resemble caddisflies.  Despite what some books say, the stiletto-shaped larvae of brown lacewings do not (cannot, because they lack dorsal setae and tubercles to stick things to), disguise themselves by fastening the dry shells of their prey to their backs (green lacewing larvae do and are sometimes called “trash bugs” for their troubles).  Larvae use their long abdomen as an aid in climbing, and they have pincer-like mouthparts designed for piercing their prey and then sucking out the juices http://bugguide.net/node/view/471809.

Brown lacewing adults and larvae richly deserve their nicknames of “aphid lions” and “aphid wolves,” but they also prey on small critters like mealybugs, white flies, spider mites, scales, and on insect eggs (including those of their confreres).  Despite their good camouflage, brown lacewings are eaten by birds, ladybugs (fellow aphid-eaters), dragonflies, and spiders.

Because their list of food items includes some agricultural pests, and because the adults are relatively long-lived (several months) and the females relatively fecund, they have been deployed to act as biological controls (you can buy them).  In a 1923 “biography” of a brown lacewing named Micromus posticus (much of the brown lacewing literature is pretty dusty), Ohio Agricultural Station researcher Clifford R. Cutright noted that a brown lacewing may eat 41 aphids during its larval stage and an adult female may lay more than 450 eggs.

According to “The Life Histories and Stages of Some Hemerobiids and Allied Species (Neuroptera)” by Roger Smith, in the Annals of the Entomological Society of America, 1923, “A very noticeable feature of females ready to oviposit is the large and much-distended abdomen…[the BugLady wonders if the plain-winged brown lacewing pictured here might be a female]  The abdomen may assume a salmon or a light amber coloration between the sclerites because of the eggs within.  They walk about excitedly, stop suddenly, and bend the abdomen forward, arching it in the middle.  The egg ….. is deposited flat on the substratum to which it adheres.  The time required for this performance is but a few seconds.”

Green lacewing eggs are set like tiny knobs on the end of stiff stalks, but brown lacewing eggs are laid directly on leaf surfaces, buds, bark, etc. near aphid populations.  The larvae are active and fleet of foot in the first instar but may become more sedentary in the second two instars.  One reference said that larvae whip their heads from side to side, a behavior that the BugLady saw in a larva that ran through a herd of aphids, brandishing one of their fallen comrades.  They often hunt on milkweed leaves, but they prefer aphids that feed on plant juices from milkweed species whose cardenolide (toxin) levels are low.  Mature larvae spin loose, double-walled cocoons in sheltered areas; there may be several generations per year, and the final brood may overwinter as a larva or a pupa (or as an adult in Southern climes) http://bugguide.net/node/view/675253.

The BugLady thinks that a few of her lacewings with streaky wings might be Micromus posticus, a species that’s found across North America but seems more common in the Great Lakes area.  This species was featured in an article suggesting that an increasing number of sightings of the species in Quebec could be part of a northern migration made possible by global climate change.  The authors pointed out that the status of fall-occurring species can be hard to determine because systematic insect collecting drops off after September.

Interesting brown lacewing factoids:

• Adults feign death when alarmed, tucking their “chins” down and their antennae between their stiffened legs.
• Their intestines are plugged and they don’t poop until they are adults (not uncommon in this group).  A silk-spinning gland occupies the larval posterior.
• Larvae “glue” themselves to the substrate by the tip of the abdomen while molting so they won’t fall during ecdysis.
• Using their middle and rear pairs of legs, brown lacewings can jump into the air like a grasshopper on their way to becoming airborne.  They leap first, and then they flap. Because they use four legs, they can launch from surfaces that might “give” beneath them, because their weight is spread out.

Kate Redmond, The BugLady
Bug of the Week archives:
http://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/

Howdy, BugFans,

Thanksgiving looms, and the BugLady would like to give thanks for Slaty Skimmers.

Dragonflies come in all sizes and colors – inch-long, orange amberwings; the slim, red presence of meadowhawks; skimmers and pennants with spotted wings; multi-colored, super-sized darners.  The BugLady appreciates flashy dragonflies, but her heart belongs to the elegant Slaty Skimmer.

Slaty Skimmers (Libellula incesta) are in the skimmer family Libellulidae, home of the most common and brightly-colored pond dragonflies.  Members of the genus Libellula (along with, in some books, the corporals and whitetails) are known as the “King Skimmers,” which Dennis Paulson describes as “some of the most familiar dragonflies to the general naturalist, as they are large and conspicuous, often with distinctive wing patterns” (and he adds the tasty tidbit that the king skimmers typically” perch with the front pair of legs folded behind the head,” which makes the BugLady want to go back and check all of her photos).  The King skimmers are sexually dimorphic, with males generally more colorful than females (juvenile Slatys are striking, but females fade to a grayish-brown).  They often perch on the top of vegetation in the sunshine, and they hunt from their perch.

Libellula incesta.  The BugLady was curious about this dragonfly’s unusual species name.  She came across an answer offered by Dennis Paulson (Dragonflies and Damselflies of the East, Dragonflies and Damselflies of the West) in an on-line forum: “Hagen [the 19^th century German-born entomologist/Harvard professor who named them] applied many strange and often undecipherable names to odonate species. For example, Sympetrum corruptum (corrupted), Sympetrum illotum (dirty), Dromogomphus spoliatus (plundered), Brechmorhoga mendax (lying, deceiving), Enallagma praevarum (unsteady), Enallagma ebrium (drunken).

Sid Dunkle and I, in our checklist of North American odonates, tried to figure out the origin of these names but failed in many cases. For Libellula incesta, we wrote ‘incestuous, perhaps alluding to looking like a hybrid between other closely related species,’ but this was pure speculation. Hagen never explained the etymology of any of his names, and they will remain unexplained.”

They are a Species of Special Concern in Wisconsin, which means they’re a species that we’re keeping an eye on because they occur in small numbers and/or have a very limited distribution in the state.  The purpose of the designation is to raise awareness of a species before it reaches a critical level that would cause it to be listed as endangered or threatened.  The Slaty Skimmer is both low in numbers and limited in distribution, but not because of a dwindling population or habitat destruction; it is scarce because it’s just moving in, spreading northwest from its range from the eastern/southeastern US.  Check out the Wisconsin Odonata Survey (http://wiatri.net/inventory/odonata/) for information on the range and status of Wisconsin dragonflies and damselflies.

Slaty Skimmers are one of three dragonflies in Wisconsin that are closely-related, very similar-looking, and very rare (in this state, anyway).  The slightly smaller Spangled Skimmer (Libellula cyanea) http://bugguide.net/node/view/946958/bgimage, so-called because it has black and white stigmas (pigmented spots toward the wing tips), also seems to be extending its range into the state from the east.  The slightly larger Great Blue Skimmer (Libellula vibrans), on the other hand, is fading from this part of its historical range but is secure east of Wisconsin.  With its teal-colored eyes and paler blue color, the Great Blue Skimmer (http://bugguide.net/node/view/1084271) could easily be mistaken for a male Eastern Pondhawk (Erythemis simplicicoll) is, also pictured in this episode (the “Slaty Skimmer” shown at the insectidentification.org. website is, in fact, an Eastern Pondhawk – some of their other info is also bogus, and their description of the naiad concludes with “They look like insects themselves in this life stage.” Caveat emptor).  Male Pondhawks have green eyes and faces, and their thorax may be blue or greenish, but they have white cerci (which makes the BugLady want to go back and check all of her photos).  Females and juveniles of the three skimmers can be tough to tell apart, and the BugLady included here a picture of a juvenile skimmer that she was hoping to make into a Great blue Skimmer, because of its more-extensive black wing tips and lighter face, but female Slatys can be variable.

Males are territorial and hostile, defending stretches of shoreline, and an approach by an intruding male results in aggressive displays, loop-the-loops, and chases.  They are most active in the morning.

Researchers Wade Worthen and Christina Phillips studied their interactions with other dragonflies, deploying zip lines at different heights over a pond and reeling dead dragonfly decoys of four species of varying sizes over the water.  Their initial hypothesis – that Slaty Skimmers would investigate smaller species that appeared higher over the pond – proved false.  Slaty Skimmers were more interested in decoys that “flew” lower and that more closely resembled the Slatys themselves.

Females are rarely seen at the water’s edge unless they’re in the mood, and they may breed while still in their juvenile coloration (as a general rule, a higher percentage of dragonflies within 50 yards of the shore are males, and a higher percentage of dragonflies 100+ yards away from the water’s edge are females and immatures).  Mating is a brief affair that starts in the air and continues on a perch (credit to BugFan Freda for her shot of the happy couple).  A female may lay a few thousand eggs, tapping them from the tip of her abdomen onto the water’s surface (splashing a lot in the process) or throwing them into vegetation.  She is guarded from the air (but is not physically gripped) by the male as she oviposits.  Female Slaty, Great Blue, and Spangled Skimmers routinely toss eggs onto damp, muddy shorelines along with some droplets of water.

Slaty Skimmers are found around wooded ponds, marshes, lakes, and very slow-moving streams with muddy bottoms, and their naiads are benthic (they live in the muck) and can tolerate low levels of pollution.  They are not known to be migratory, but the Great Blue Skimmer is somewhat migratory along the Atlantic Coast.

FYI, entomophagists, Slaty Skimmers have been known to carry liver flukes that they pick up as naiads.

For BugFans who don’t mind a bit of blood and gore, great pictures of dragonflies as prey (including some very desirable species) can be found at this site http://www.thehibbitts.net/troy/photo/odonata/dragonfly_%20predators.htm.

Kate Redmond, The BugLady 

Bug of the Week archives:
http://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/

Salutations, BugFans,

The BugLady saw these Splendid dwarf spiders (Hypselistes florens) when she did her dandelion survey (of recent BOTW fame) (unlike the large orb weavers of fall, these dwarf spiders overwinter in their almost-mature, second-last stage, ready to go in spring).  Later, she saw females making/tending to egg cases on blades of grass; she’s seen the white web patches for years and wondered who was responsible for them.

Splendid dwarf spiders belong to the spider family Linyphiidae, a large family (4,300-plus described species, and possibly that many undiscovered) of small spiders.  Linyphiids are second in species numbers only to Jumping spiders and are a dominant group of spiders in the cooler regions of the Northern Hemisphere (where they’re sometimes seen walking on snow).  Around the globe, they are known as sheetweb, dwarf, hammock and money spiders (in some countries, according to folklore, a dwarf spider walking on you has come to spin you a new set of clothes).  They belong to the subfamily Erigoninae, the dwarf spiders, whose members average about 2 mm in length – so small that it can be easier to identify them by their webs.

Bugguide.net tells us that “Sheetweb weavers are found in all kinds of habitats: anywhere there are small insects and at least a little vegetation to build their webs on.”  In fact, according to the University of Michigan’s BioKids site, “Some species in this family make their webs in the footprints of large animals, including people.”  Linyphiids are enthusiastic “ballooners,” both as spiderlings and adults, able to travel great distances on gossamer strands of silk.

Why “sheetweb?  Their three-dimensional webs are spun on or near the ground or in leaf litter http://bugguide.net/node/view/227371/bgimage.  In a typical web, a sheet (or two) of horizontal silk lies below a loose array of “knockdown” strands that are designed to intercept insects and cause them to fall onto the sheet.  The spider hangs (often upside-down) beneath the web, popping up when it detects the vibrations of its struggling prey.  It bites through the web, injects venom into its prey, and pulls it back down through the web.  Dwarf spiders eat invertebrates including springtails, ants, flies, planthoppers, and tiny beetles (in their own, small way, they do their bit for agriculture by feasting on some crop pests); they’re eaten by ground beetles, small amphibians, ants, centipedes, and other spiders.

Spiders have appendages on their face called palps; the palps of mature males are very conspicuous and are often compared to boxing gloves.  They have two body parts – an abdomen and a combined head and thorax called a cephalothorax.  The carapace (dorsal side of the cephalothorax) of males of many species of dwarf spiders is decorated with grooves or pits or projections or modified hairs.  These are assumed to play a part in courtship, and females of some species are known to grip them with their chelicerae (jaws) while mating.  Like tree crickets and some other arthropods, males of some species of dwarf spiders provide a bonus for their mates; a liquid that is secreted by special (prosomic) glands on his head is consumed by the female.

Sheetweb spiders can vocalize.  Like a katydid that strikes a rough spot on one wing against a rough spot on the other to make sound, a sheetweb spider rubs together gritty areas on its fangs to do the same.  They are only social during the mating season.

Splendid dwarf spider!  What a grand name for a spider that weighs in at less than 3/8” and can easily sit on the eraser of a #2 pencil (if anyone remembers what those are).  Splendid dwarf spiders are found from coast to coast, mostly across the northern half of the US and southern Canada.  They managed to cross the Atlantic – one male and two females were recorded in England in 1908 – but they did not establish a population there.

A few of the eight eyes of some males in the Erigoninae, including the Splendid Dwarf spider, are on mounds near the top of the head: http://bugguide.net/node/view/381724/bgimage.

The books say that this species makes its egg case close to the ground, but the BugLady finds them on grass stems that are two or three feet higher.  These common (but well-hidden) little spiders live for about a year.

Kate Redmond, The BugLady

Bug of the Week archives:
http://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/

Howdy, BugFans,

When the BugLady started researching zebra mussels (which were originally going to solo here), she was reminded that the story of this non-native, invasive mussel is inextricably entwined with that of an equally-alien and equally-invasive mussel, the quagga mussel – and also that we are, as a species, appallingly slow learners.

Zebra and quagga mussels are in the Phylum Mollusca, a diverse bunch that includes snails and slugs, limpets, clams, scallops, squid, octopi, and cuttlefish; within the Mollusks, they’re in the order Bivalva, and in the family Dreissenidae.

Zebra mussels (Dreissena polymorpha) and Quagga mussels (Dreissena bugensis) have traveled far from their native haunts, the Caspian Sea drainage of western Russia, but they have settled nicely into their new homes, the Great Lakes and a number of inland lakes and rivers – hitchhiking on boats, boots, bait buckets, and on the feet of waterfowl.  Zebra mussels were first identified in the US in 1988, in Lake St. Clair, just east of Detroit, and they reached Wisconsin by 1992.  In 2010, they were found in 130 Wisconsin lakes and rivers.  The first North American quagga mussel was found in 1989, but it wasn’t positively identified until 1991.  Here are some animated maps of the mussels’ spread between 1986 and 2015 (click on the “real-time maps”): https://nas.er.usgs.gov/taxgroup/mollusks/zebramussel/ (the BugLady loves animated maps), and graphics of their spread in the Lake Michigan basin alone: http://sanctuaries.noaa.gov/science/condition/tbnms/images/fig36_lg.jpg.  The two mussels are now found in 29 states, and the National Wildlife Federation website estimates that the Great Lakes alone are home to 10 trillion (with a “T”) zebra and quagga mussels.

Did they hoof it over here on their own?  They did not; like most of us, they came over on the boat.  They undoubtedly arrived in the Great Lakes in the ballast water of ships that ply international waters, as have a rogue’s gallery of hardy gatecrashers (more than 180 species, so far), and a number of North American organisms have been toted to Europe in the same fashion.

Here’s the physics of it: while they’re in their home ports, European vessels take water (plus whatever’s swimming in that water) into tanks built on the inside of the ship’s hull, and this “ballast water” helps keep the ship upright.  A ship carrying a small cargo needs lots of ballast; as it loads more cargo, it discharges ballast water (plus whatever’s swimming in it) https://en.wikipedia.org/wiki/Ballast_water_discharge_and_the_environment#/media/File:Ballast_water_en.svg.  Ocean-going ships routinely enter the Great Lakes via the St. Lawrence Seaway, and equally routinely, emptied their ballast water into the Great Lakes.  In 1993, a (difficult-to-enforce) law was passed that required incoming ships to replace their home-grown ballast water with ocean water before entering the Seaway,

In 2011, New York State, gatekeeper for the St Lawrence Seaway, proposed stiff, new regulations about ballast water management/treatment.  Three Midwestern governors pushed back, citing concerns about job loss (although some innovative alternative transport was suggested at the time).

Zebra and quagga mussels turned out to be plenty adaptable – although they originated in salt/brackish water, they quickly adjusted to fresh.  They are bottom dwellers that live in clusters in great, huge, astronomical numbers on the floors of lakes (at one site in Arizona, quagga mussels number 35,000 per square meter).

When quagga mussels arrived, they out-competed the zebra mussels.  Although their life histories are similar, the two mussels prefer somewhat different habitats.  Zebra mussels like water depths of 6 to 30 feet, and quaggas can live as deep as 400 feet, so zebra mussels grow closer to shore, and quaggas thrive through the deep basins of the Great Lakes.  Quaggas necessarily have a much wider temperature tolerance.  Both species eat all day, but quaggas continue feeding during the winter, when zebra mussels are dormant.  Pictures of the two may be found at: https://nas.er.usgs.gov/queries/factsheet.aspx?speciesid=5.  The BugLady’s photos show them as most people experience them – as “empties,” cast up on the beach.

Mussels are “filter feeders,” which means that they suck water in through a siphon and run it over their gills.  Food particles, zooplankton, phytoplankton, and nutrients (and pollutants) are strained out of the water by cilia in the gills and are moved to the clam’s mouth, and the water is expelled through a second siphon.  Wastes are released in mucous-covered packets called pseudofeces (vocabulary word of the day).  An inch-long zebra mussel can filter a liter of water a day.  One liter per day x Astronomical numbers of mussels = large bodies of very clean water.

At first, some people were thrilled – “Yay, the lake is clean again” shouted the headlines.  Cities around Lake Erie had been battling pollution in the form of algal blooms due to excessive nutrients (fertilizer) in the water.  In short order, you could see the bottom of the lake again (it’s called “nutrient bioextraction,” and it can be a useful tool in controlled situations where the bivalves are removed when they’re finished eating and processed into animal food or, ironically, fertilizer).

However, the water was crystal clear because there were so few nutrients left in it, and native species that depended on the food in those liters of water were out of luck.  It was an attack on the base of the food chain/web.  Zooplankton feed on phytoplankton and are fed upon by larger animals, including tiny fish, which, in turn, feed bigger fish and a variety of other vertebrates.  But, nutrient robbing is not the only problem with these mussels.

• Quaggas eat algae, but they’re picky, and non-toxic algae are their favorites.  What’s left after they feed is higher concentrations of the more troublesome algae.  Light is able to penetrate deeper into the nice, clean water, opening the door for more algal blooms.  Decaying algae, some carrying harmful bacteria, wash up on the shore.
• The clear water can allow thick growths of other aquatic plants, too, fertilized by nutrient-rich mussel poop.  Dense aquatic vegetation discourages swimming, fishing, and boating.
• Our native shellfish are indicators of the health of their environment.  The invasive mussels turn lake beds hard and lumpy, with wall-to-wall shells, making it hard for native bivalves to find favorable habitat.  To add insult to injury, zebra mussels will piggyback on native mussels, hindering their feeding and ultimately smothering them.  Great picture at: http://www.startribune.com/mussel-bound-lakes-could-imperil-birds/133021828/.
• Old zebra and quagga mussel shells wash up on shore, often in sharp fragments, problematic for barefoot beach-goers.
• Zebra mussels overgrow anything that stands still long enough, especially pilings and other underwater surfaces, and they clog utility water intake/cooling pipes, requiring costly fixes.  Researchers in a few northern lakes have observed an odd (and one-sided) association – zebra mussels growing on the backs of clubtail dragonfly naiads (immature clubtails may live underwater for several years, giving mussels plenty of time to gain a foothold).  Their exoskeletons are effectively glued shut by mussel filaments on the thorax, where the exoskeleton normally splits to release the adult dragonfly, so naiads crawl up on shore and die there, unable to emerge. 
• As they feed, quagga and zebra mussels accumulate toxins, with some pollutants occurring in their tissues (and their pseudofeces) in concentrations measuring many thousands of times higher than in the surrounding water.  Those toxins (including Clostridium botulinum) get passed up the food chain in a process called biomagnification.
• A mass of pseudofeces on the lake’s floor requires oxygen in order to decompose.

Lake Superior has mostly avoided this mess, probably due to a combination of its much colder temperatures, lower levels of nutrients in the water, and its water chemistry – very little calcium for growing strong shells.

Mussel reproduction is external and chancy.  Males and females release their bodily fluids into the water, nature takes its course (aided by water currents and propinquity), and fertilized eggs hatch into a life stage called veligers.  An adult female can produce as many as a million eggs annually, and her life span is three to five years, but the attrition rate for eggs and veligers is huge (they’re even eaten by filter-feeding adults).  Mom and Dad may be stuck in one spot, but their offspring are, temporarily, free-swimming, and currents can spread them great distances.  Veligers swim and feed for four or five weeks before they must attach, and they mature by their first birthday.

What slows these critters down?

• Fish, like yellow perch and redeye sunfish, and waterfowl, especially diving ducks like goldeneye and scaup, have learned to love the invasive mussels (98% of a Lesser Scaup’s diet is zebra mussels).  Kudos also go to the alien, quagga-eating round gobi fish.  Alien species that become invasive do so because they have left their native predators behind.  In this case, the predator caught up with the mussel, but, alas, this aggressive fish damages native fish populations, too.
• A patented bacterium called Zequanox targets these two mussel species only and has a 90% mortality rate, but is far too expensive to apply to a Great Lake.
• Unusually warm water – In 2001, the water temperature in parts of the Upper Mississippi reached 89 degrees F, and masses of zebra mussels died.

Good news-Bad news: For zebra mussels in the Great Lakes, the show is over, but they’ve simply been replaced by quaggas, and scientists doubt that the Great Lakes will ever return to their pre-alien-mussel state.  At this point, Lake Michigan (the 6^th-largest freshwater lake in the world) is essentially a man-made ecosystem that’s being managed as a fishery, because the base of the food chain/web is so messed up.  Excellent article at: http://archive.jsonline.com/news/wisconsin/how-invasive-species-changed-the-great-lakes-forever-b99297128z1-267010971.html.

For those people whose attitude toward alien species is “Get over it – A species is a species!  New species = more biodiversity,” the BugLady has one word. “Seriously???”

For all your invasive species needs, remember our own Southeastern Wisconsin Invasive Species Consortium (SEWISC), https://sewisc.org/, a wealth of information about invasive species already in the state and on the horizon.

Be assured that the BugLady did not use any of the information presented in the article about “Zebra Muscles” (ain’t Spellcheck grand?).

Kate Redmond,  The BugLady

Bug of the Week archives:
http://www4.uwm.edu/fieldstation/naturalhistory/bugoftheweek/

Howdy, BugFans,

The BugLady wrote this article about “The Mighty Muskrat” for a recent issue of the BogHaunter, the newsletter of the Friends of the Cedarburg Bog (which you should all join).  She would like to thank the mighty muskrat for its dedicated work in maintaining wetlands, the homes of an astonishing array of aquatic insects (her favorites).

Spring, 1928: “The Birch Island Fur Farms, Inc. of Saukville, announced that it would be starting a fur farm for the breeding of muskrats, beavers, raccoons, and other fur-bearing animals at Mud Lake near Saukville.” “The Crossroads,” The Saukville, Wisconsin Area, by John Boatman

Some sources say that the muskrat (Ondatra zibethicus) was so-named because it has musk glands and it looks like a large rat (it’s about the same length as a Norway rat but, at 1 ½ to 4 pounds, significantly outweighs one), but its name is probably much older. It was called “moskwas” by the Abenaki and “muscascus” (“it is red”) in one of the Algonquian languages; its genus name comes from the Huron name for muskrat. Today, it’s commonly called musquash, marsh hare, and musk beaver.

Muskrats are described as “semiaquatic rodents,” and they’re superbly adapted for life in a wetland. Their short front legs, great for digging, are too often applied to the banks of earthen dams, ponds, levees, and streams, which gets them in trouble with humans. Webbed back feet help to propel them when they swim. That scaly “rat tail,” about the same length as the body, steers them, helps move them through the water (they tuck in their front legs and move, torpedo-like, through the water), and braces them when they sit on land. An undercoat protects them from frigid water, and air that gets trapped in their fur helps them float.

It gets even better – muskrats can close off their ears and nose underwater. Like beavers, their lips are located in back of their teeth rather than in front of them, so they can hold vegetation in their mouths and even chew while swimming without flooding their throats! Like waterfowl, they practice “regional heterothermia” – that is, they can keep their feet and tail cooler than their core. Muskrats can tolerate higher concentrations of carbon dioxide than many diving mammals – handy for an animal that can spend 15 minutes under water.

Muskrats eat vegetation that they find in and around the water, snipping it off with their large incisors, but they may feed on crops in adjacent farm fields, too. They eat a variety of small animals like fish, crayfish and frogs. Muskrats don’t hibernate, and they maintain the same diet in winter. Severed cattails on the water’s surface and trails through the floating vegetation are signs of their presence.

Like other small mammals that are heavily preyed on (in the muskrat’s case by mink, foxes, coyotes, birds of prey, otters, snapping turtles, and even large pike), they breed early and often – at least twice each summer in our area and five times in the south. There are generally six to eight young per litter.

Muskrats are found throughout North America (except Florida), and south a bit into Mexico. They were introduced to Europe a century ago and are not appreciated in low-lying areas where dikes hold back the sea.

Besides excavating tunnels in stream banks, they use mud and aquatic plants to construct lodges called “push-ups” that can rise four feet above the water level and be eight or ten feet long. Lodges are built in wetlands that are at least two to four feet deep, and they provide protection from predators, a nursery, shelter in winter, and a home base for under-the-ice foraging. Muskrats also make smaller feeding platforms, and both the lodges and the feeding platforms provide mini-islands that waterfowl, turtles, and snakes can nest or loaf on.

Muskrats defend territories that they mark with “scent posts” – musk deposited on a small pile of leaves. These benign-looking animals will fight fiercely, and sometimes lethally, over potential mates. They live in family groups, from which the young are evicted if the marsh gets too crowded. A three-year-old muskrat is a very old muskrat.

Like beavers, muskrats are considered “keystone species” because of the way they shape their habitat. They live in a variety of wetland types but favor marshes because the water depth doesn’t fluctuate a lot. There, they are marsh managers.

Their populations are cyclical, with booms and busts over a six to ten year period. They love cattails and yellow water lilies, and when muskrats are abundant, their feeding on favored plants determines the vegetative composition of marsh and creates open water that is appreciated by waterfowl, wading birds, fish, frogs, and other aquatic animals. Too abundant, and they will strip a marsh of plants, turning it into a mud flat (a phenomenon called an “eat-out”) and allowing erosion. Too scarce, and the eye of the marsh grows closed again.

The fur farm was never built, but if it had been, the muskrat pelts would have been marketed as “Hudson seal” (skunk fur was sold as Alaskan or Black sable). Muskrat meat is edible, but not popularly indulged in, although Catholics in southeastern Michigan enjoyed a long-standing muskrat-dispensation from the rule that prohibited the consumption of meat on Ash Wednesday and Fridays in Lent. The Native Americans who lived around the edge of the Bog undoubtedly trapped muskrats for both food and for their warm fur.

The BugLady