Bug o’the Week – Silver-spotted Skipper

Greetings, BugFans,


This wonderful caterpillar dropped down onto the railing the other day while the BugLady was eating breakfast on the porch (those orange spots on its head aren’t eyes, they’re just there to scare you).  The Silver-spotted skipper was mentioned briefly ten years ago in a general BOTW about skippers, in which the BugLady confessed, not for the last time, that she is Skipper Challenged (Brock and Kaufman, in the Field Guide to Butterflies of North America, say that “Beginners are often driven to despair by the skippers because there are so many of them and because they are so subtle, so challenging to identify.  Experienced butterfly watchers may love the skippers for exactly the same reasons.”).  It deserves an episode of its own.

What are Skippers?  They are (mostly) small, orange and brown butterflies in the family Hesperiidae, and they comprise about a third of all butterfly species.  Generally, they are big-eyed, chunky, short-winged butterflies that hold their wings in a distinctive, partially-folded position at rest.  Their knobbed antennae end in a hook-like tip.  Despite their stubby wings, they move fast, and they’re named for their swift and bouncy flight.  Although moth-like, skippers are neither moths nor the Missing Link between butterflies and moths but are in the superfamily Papilionoidea with the rest of the butterflies.

European skippers, of recent BOTW fame, are in the Grass skipper subfamily.  Silver-spotted skippers are in the Spreadwing or Dicot skipper subfamily, “dicot” being a nod to the fact that their larval food plants are not grasses (many Spreadwing species favor members of the Pea family, both wild and ornamental).  These are larger-than-average skippers that, unlike their Grass skipper relatives, tend to rest with wings folded.


Silver-spotted skippers (Epargyreus clarus) are found in grasslands and woodland edges across southern Canada, in most of the Lower 48 states, and into northern Mexico; and Brock and Kaufman call them “the most easily-recognized skipper across North America.”


Like the Grass skipper caterpillars, Spreadwing skipper caterpillars camp out in leaf shelters that they fasten with silk https://bugguide.net/node/view/1558970/bgimage.  Wikipedia, whose entries on insects are often limited to a few lines about taxonomy and range, waxes positively poetical about Silver-spotted skippers, including a detailed description of building a leaf shelter (https://en.wikipedia.org/wiki/Epargyreus_clarus).  A shorter account, from the Wisconsin Master Gardeners website, says “The young caterpillars live in a shelter created by a folded flap of leaf cut from the leaf margin and tied down with silk threads, while later instars tie together several leaves with silken threads to create a protective nest. They abandon smaller shelters as they grow and move to make new shelters. They leave these shelters at night or on cloudy days to feed on nearby foliage.”  Caterpillars overwinter in their leaf tents and eventually pupate there.

The shelters provide only a modicum of protection from predators – despite being disguised as a clump of leaves, the caterpillars are preyed upon/parasitized by insects like assassin bugs and ants and are collected by foraging wasps to feed their larvae.  Like other skippers, Silver-spotted skipper caterpillars have a unique way of hiding from parasitic wasps that find hosts for their young by following the scent of caterpillar droppings (frass); see the final paragraph of https://uwm.edu/field-station/skippers/ for details.  It’s the same theory used by birds that carry their nestlings’ fecal sacs away from the nest – piles of excrement mean that someone’s home.


Males perch on –and defend – plants from which they watch for females, and they venture out to check anything that flies past (butterflies don’t have very good eyesight).  Eggs are laid singly https://bugguide.net/node/view/1542535/bgimage, sometimes on a host plant, but sometimes only near it (in which case the caterpillar must hike around until it finds the right plant).

In researching this species, the BugLady was reacquainted with one of her favorite resources, the huge (150+ years) and thoughtfully analyzed database of the Butterflies of Massachusetts website http://www.butterfliesofmassachusetts.net/silverspot-sk.htm.  They point out that sun-loving species of butterflies benefited from the arrival of European settlers, who turned forests into agricultural fields.  In the case of the Silver-spotted skipper, its status in New England before the early 1800’s, when various species of locust trees from the southern US began to be introduced there, is uncertain.  If it was there before 1800, then its host plants were hog peanut and groundnut (both important food plants for the Native Americans), and it adopted locust trees later.  Alternatively, it is a southern species that arrived with the locusts.  A similar story could undoubtedly be told of its status in Wisconsin.


According to the “Butterflies of the Pacific Northwest” website, Silver-spotted Skippers in the Southeast have discovered Kudzu (something had to, according to the Reinartz Law of Biomass Availability – a.k.a. If You Grow It, They Will Come – Eventually), and they are enjoying a population boom there.

Adults use their long proboscis to nectar on a variety of wildflowers, most of them red, blue, pink, or purple, and they also get minerals from bird poop.  They are sometimes referred to as “nectar thieves;” apparently, they can reach the inner flower parts without transferring pollen.  When they’re not feeding, or when it’s cloudy or hot, the butterflies may hang upside down under leaves.


Two other nice bug information sites are the University of Florida’s “Featured Creature” series (http://entnemdept.ufl.edu/creatures/) – http://entnemdept.ufl.edu/creatures/bfly/silver-spotted_skipper.htm, which tells us that the caterpillars defend themselves by regurgitating “a greenish, bitter-tasting, defensive chemical.”  And another Bug of the Week, (http://bugoftheweek.com/blog/) this one by Michael J. Raupp, PhD, Professor of Entomology, Extension Entomologist, at the University of Maryland, who refers to Silver-spotted skippers as “rambunctious” http://bugoftheweek.com/blog/2016/8/15/now-you-see-em-now-you-dont-silver-spotted-skipper-caterpillars-iepargyreus-clarusi.


One last thing about Silver-spotted skippers, from the Massachusetts Audubon Society website: “Silver-spotted Skippers may occasionally be heard in the field. Their rapid wingbeats produce a whirring sound audible at close range.”


Go outside – listen for bugs!


Kate Redmond, The BugLady


Bug of the Week archives:

Bug o’the Week – Maple Spanworm 2

Howdy, BugFans,

Another week, another Maple Spanworm.  This one, the Large maple spanworm (Prochoerodes lineola) is also in the family Geometridae.  The BugLady didn’t have to play her usual game of Identification Roulette because, of the seven New World species in this primarily tropical genus, this is the only one that occurs in eastern North America.

Like last week’s Maple spanworm (Ennomos magnaria), the adult is a fall-flying, nocturnal leaf mimic, and the caterpillar is cleverly disguised as a twig (here’s a “frosted” https://bugguide.net/node/view/942223/bgimageand an “unfrosted” version of the caterpillar http://bugguide.net/node/view/565483/bgimage).  It’s a nice-sized moth, about 1 ½” to 2” across, with a few small points on the edges of the wings.  There’s a lot of variation in color, http://mothphotographersgroup.msstate.edu/species.php?hodges=6982, but the dark line that bisects the front wing (the post-medial line) is diagnostic; it has pale edges and a sharp angle near the tip of the wing.

Wagner, in Caterpillars of Eastern North America, tells us that “Seasonal phenology remains unclarified in the Northeast, where there seems to be a single principal generation, with mature caterpillars from June through August; southward with two to three generations.”  Both Wagner and Sogaard, in Moths and Caterpillars of the North Woods, say that it overwinters as an egg, but other sources say that it overwinters as pupa.  Here’s a nice series of pictures of its life cycle: https://bugguide.net/node/view/1119588/bgimage.

A publication by the North Carolina Parks Department says “We suspect that few individuals overwinter in North Carolina and that we get annual migrations in the spring that are able to establish temporary, but recurrent breeding populations throughout the state.”  The 2018 “Checklist of Wisconsin Moths” (Ferge, Balogh and Johnson), though, lists it as a resident here, http://www.wisentsoc.org/wp-content/uploads/2018/06/WI-Moth-Checklist-June-2018.pdf 

Like last week’s Maple spanworm, the caterpillar does not limit its diet to maple; it’s also found on woody plants like birch, willow, tamarack, aspen, blueberry, cherry, and dogwood, and on herbaceous plants like soybeans, sweet-fern, and members of the geranium family.

The Large maple spanworm was one of a number of moths studied by researchers Amanda Soutar and James Fullard in an effort to find out more about how moths avoid predators at night.  They say that:

  • Nocturnal predators depend on hearing and smell more than on sight to locate prey.

  • The bats they observed had two hunting modes – “aerial foraging,” in which bats use sonar to “ping” aerial prey (many groups of insects have evolved “ears” that allow them to detect bats), and “substrate gleaning,” in which bats fly low over vegetation and pick up the sounds of their prey using a kind of echolocation that eared moths can’t hear.

  • Nocturnal moths have larger eyes than those that fly by day (and the more nocturnal they are, the bigger their eyes).  Eye size is also correlated with moth size, but there’s no significant difference in eye size between eared and earless moths.  The researchers say that “It’s possible that all large moths use vision to detect approaching bats.”

  • Moths with ears get important information about the presence of bats that lets them make a decision about whether to fly or not to fly.  Larger species of eared moths are a bigger target for echo-locating bats, but they have more sensitive hearing, which evens the playing field.

  • Moths without ears employ “passive” defenses – they are less likely to fly at night than eared moths are (surface-gleaning bats can’t detect silent, stationary prey); they may fly lower to the ground or faster or more erratically or for shorter distances than their eared counterparts, and many are species that are out early in the season, before bats migrate back north.

  • Moth reproduction requires a male to fly to a female, which puts earless moths at a disadvantage.  To compensate, they may live longer, or males may have more sensitive antennae for picking up a female’s chemical trail (some authors refer to the female’s pheromones as her “song”).

See the whole article at: https://academic.oup.com/beheco/article/15/6/1016/205999.

[An Aside: From an article called “Seven Surprising Facts about Moths I Learned on my First Mothing Night,” “Fact #1 – The names are in Latin! When Peterson’s Field Guide to Moths was authored with Charles Covell in 1984, the publisher told him he needed to include the common names.  Peterson said that there were no common names!  He was then told to make them up, which he did using the Latin to help with some of the naming.  The problem with learning only the common names is that others have also named them something completely different.”]

Finally, Maple spanworm seems to be a popular name – there’s also a Lesser maple spanworm (Macaria pustularia https://bugguide.net/node/view/287220) (which the BugLady doesn’t have a picture of – yet); about its descriptive species name, bugguide.net says “PUSTULARIA: from the Latin ‘pustulare’ (to blister); the third orangish-yellow marking along the forewing costa [representing the top of the PM line] is reminiscent of a pustule that has broken and leaked a trail of pus down the wing – not a very nice mental image, but a good way to remember this species.


Kate Redmond, The BugLady

Sugarbush House

For 50 years, maple sugarin’ has been not just a program at Riveredge, but a way of life. Perhaps nothing better exemplifies the mix of whimsy, fun, learning, and natural wonder that makes Riveredge, well, Riveredge…than the eyes of a child. Imagine a child who has just connected the maple syrup on a steaming pancake to the sap from a tree she just helped tap. This sense of wonder comes to us thanks to hundreds of people who, for five decades in early spring, have devoted themselves to making it all happen; including folks with interesting names like The Big Sap, Father Fire, Picklepuss, Sap Queen, and Maple Madman. And now this year longtime Riveredge supporters Mal, Jill, and Jamie Hepburn (Jamie being a Riveredge Kid himself), have teamed up with the Hepburn “Bootstrap” Foundation, and Ozaukee Bank’s Gift to the Future Fund to make a coordinated gift to Riveredge. A gift which will fund 100% of the cost to construct a new, but still rustic, lodge style Sugarbush House.
The Sugarbush House is being built on the vacant site of Ernie Pochert’s (aka “Father Fire”) house in “Ernie’s Woods.”  This fitting location is in the heart of Riveredge’s best Sugarbush and Ernie (who passed in 2014 and was a long time iconic maple sugaring volunteer at Riveredge), embodied all the fun and dedication that makes this “fifth season” all that it is.
 The dedication plaque will read: “This Sugarbush House is being built expressly for all the Riveredge Kids who will visit this wondrous nature sanctuary in the years to come. It is dedicated to Andy, Don, Lefty, Ernie and to hundreds of others…who worked tirelessly to reestablish the surrounding forest. And at the same time helped to build Riveredge Nature Center’s 50 year tradition of honoring the land.”
 The Sugarbush House was designed by Architect Don Stauss of Mequon and is being constructed by Sauermilch Contractors of Sheboygan.
 We thank the Hepburn family and all the many people who are making this new facility a reality. The Sugarbush House will allow the expansion of not only Riveredge’s maple sugarin’ programs enjoyed by thousands of students and community members each year, but also will be used as a year-round classroom space expanding capacity to meet the needs of Riveredge’s growing  educational programs. Construction on the Sugarbush House has already started, and we plan to have it open in time for next season’s sugarin’ celebrations!
If you are interested in being part of this or other upcoming building projects at Riveredge, please reach out to Jessica Jens, Executive Director.  We invite you be part of this exciting adventure — for without generous partners and incredible kindness such as this, Riveredge would not be here today!

Bug o’the Week – Maple Spanworm

Howdy, BugFans,

Isn’t this moth exquisite!  It’s one of several moths in the family Geometridae that go by the same name – Maple spanworm (more about that in a future episode). And it’s one of several “new bugs” that the BugLady saw for the first time this year. Here’s a glamor shot of one http://ottawa.moths.ca/geometridae/pages/06797-ennomos-magnaria-A2.html.

Anyway, Geometrids – Geometer moths – are, as long-time BugFans know, named for the way their caterpillars walk.  Geometrid means “earth measurer,” and the caterpillars are fondly nicknamed “inchworms,” “loopers,” and “spanworms” because of their gait. Lepidopteran caterpillars have three “true” legs in front, on their thorax (caterpillars are divided into three sections, just like their elders).  The rest of that long body is supported by prolegs – fleshy, hydraulically-powered stubs tipped with hooks (crochets) for gripping the substrate https://bugguide.net/node/view/153809.  A full complement of prolegs is five pairs, the hindermost being a pair of anal prolegs at the tip of the abdomen.  Geometer caterpillars are missing two or three pairs of prolegs between the true legs and the anal prolegs, and the result is that instead of uniform undulation, the inchworm reaches its front end forward and then arches to pull the rear end up to it.  For a full explanation of prolegs and some super photos, see http://www.thecaterpillarlab.org/single-post/2016/1/6/SPOTLIGHT-ON-CATERPILLAR-ANATOMY-PROLEGS.

Several sources said that Maple spanworms (Ennomos magnaria) are a sign that the days of summer are numbered (the BugLady found two of them at the start of September).  They’re found around woodlots and swamps across southern Canada and the northern half of the US http://mothphotographersgroup.msstate.edu/species.php?hodges=6797.  Adults are nocturnal, and may rest on the sides of buildings by day.

With a wingspan of 1 ¾” to 2 ¼” they’re decent-sized moths.  What cool wings!  Their unevenly-scalloped edges explain this moth’s other common names – Notch-wing moth and Notched-wing geometer.  What a dynamite color!  And what a posture – like one of those figure-skating moves where the skater holds her foot in back of her head!  There are plenty of moths that are leaf mimics, but this one takes it to another level by imitating dry, curled leaves.

The caterpillars take twig mimicry to a new level, too.  Swellings on the caterpillar look like bits of twig anatomy – leaf scars, bud scars, and lenticels: https://bugguide.net/node/view/1484763/bgimage,https://bugguide.net/node/view/132141/bgimagehttps://bugguide.net/node/view/818291/bgimage,  https://bugguide.net/node/view/291625/bgimage.

David James, et al, in The Book of Caterpillars: A Life-Size Guide to Six Hundred Species from around the World, tell us that, “Maple spanworm caterpillars hatch from overwintering eggs laid in rows on their host plant. Both edible and abundantthe caterpillars have evolved a remarkable ability to camouflage themselves.  So as not to create a searchable pattern for predators, the green, brown, or gray coloring of their body varies, and they also blend perfectly with their host plant by assuming a stiff, twiglike position during the day.”  The BugLady assumes that “edible,” here, means edible by the usual caterpillar-eating suspects, not in an entomophagy context.  Jim Sogaard, in Moths and Caterpillars of the North Woods, says that the caterpillars are “superb examples of ‘vegetable disguise.’”  Despite their camouflage, they are found and eaten by birds and by other insects and are parasitized by wasps.

One source pointed out that the name “Maple spanworm” is misleading because it implies that the caterpillar is a specialist feeder on maples.  In truth, its menu is so varied that its host plants include much of what grows in Wisconsin’s deciduous woods and wetlands – alder, ash, basswood, elm, hickory, birch, beech, poplar, willow, holly, and oak – and maple.

In fall, females lay eggs on a host plant, and there the eggs overwinter.  They hatch in spring and the caterpillars feed, but instead of descending and pupating on/in the ground, they spin a silken cocoon in the leaves and pupate there, emerging as adults in mid-to-late summer.

Of the caterpillar, David Wagner says in his book Caterpillars of Eastern North America, that “By flashlight, these enormous loopers are readily discovered – look for them at the end of a shoot.”

On a different topic, it’s Woolly Bear Caterpillar Time!  To find out what they’re telling us about the coming winter, see https://uwm.edu/field-station/woolly-bears/.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Cross Orbweaver Spider

Salutations, BugFans,

The BugLady is literally surrounded by Cross orbweavers (Araneus diadematus).  Egg cases were attached to the house and porch last fall, and masses of spiderlings emerged in early summer; she often has to break through a web to get out the door.  In her research, the BugLady has seen this group labeled as orbweavers, orb-weavers, and orb weavers, even within the scientific community; she’ll use “orbweavers” because it annoys Spellcheck).

They’re called orbweavers (family Araneidae) because the webs they spin are the classic, round, flat webs that we learn about as kids.  You know – Charlotte’s people.  Bugguide.net tells us that “All orb weavers spin some sort of web consisting of concentric circles (smaller circles within larger circles) with “spokes” radially going from the center outwards toward the anchor points (https://bugguide.net/node/view/1000727/bgimage) …. Most orb weaver webs are vertical (perpendicular to the ground), but there are a handful that will spin a horizontal web (parallel to the ground). Some of the webs can be extremely large (over 3 feet in diameter)” (a few webs on the BugLady’s porch have approached that size; and lately, the BugLady has had fun luring mosquitoes into them, which the large female seems to eat directly without wrapping and storing.  Hors d oeuvres).

Speaking of which, spiders are carnivores, right?  Well… mostly.  Researchers Eggs and Sanders noted in a paper in the journal PLOS that when orbweavers, including Cross orbweavers, recycle (eat) old webs, they also consume pollen and fungal spores that have stuck to the strands.  And they do it on purpose – some pollen grains are too large to “swallow” casually and have to be pre-softened externally by enzymes, just like animal prey.  They reckoned that about 25% of the diet of juvenile orbweavers is pollen.

Cross Orbweavers were mentioned briefly in a 2012 BOTW about several species of large orbweavers.  For basic information about the group, see https://uwm.edu/field-station/big-orb-weaving-spiders/.

The Cross orbweaver’s range is described as “Holarctic,” which means that it’s found in northern areas of the New World (where’s it’s an immigrant) and of the Old.  In the New World, it’s found in southern Canada and across the United States from New Jersey to northern California.  With a range like that, it’s picked up a bunch of common names, among them European garden spider, house spider, diadem spider, cross spider, pumpkin spider (a name shared by the Marbled orbweaver) and crowned orb weaver.  It’s a well-known species (because it likes people and their habitations, especially if those habitations have exterior lighting) and a well-studied one.

As is the case with most species of large orbweavers, there can be considerable color variation (and dark individuals may get lighter in color as they age), and not all of them have an obvious “cross” on the top of the abdomen, and sometimes a microscopic examination is required to make an ID https://bugguide.net/node/view/1296471/bgimagehttps://bugguide.net/node/view/1444765/bgimagehttps://bugguide.net/node/view/1458037/bgimagehttps://bugguide.net/node/view/1344384/bgimagehttps://bugguide.net/node/view/1331634/bgimagehttps://bugguide.net/node/view/713309/bgimage; and http://spaceweathergallery.com/indiv_upload.php?upload_id=148031&PHPSESSID=63o1fc8cg5takrhq187eemo2a6 (OK, the BugLady threw that in because the Aurora season is heating up and www.spaceweather.com’s “Realtime Aurora Photo Gallery” takes us there).  Males aren’t dramatically smaller than females (about 6-13mm long, to the females’ 6-20mm), but females have a rounder abdomen, especially now, when they’re gravid.

They hatch in spring, stay together until their first molt (the collective noun for spiders is a “cluster” or “clutter”), and then scatter, and spiderlings that were tiny in June have reached lunker size now, at the end of their lives.  In late summer, mature males may “adopt” immature females in hopes of a future liaison.  A male approaches a female cautiously, with lots of advance-and-retreat, and tentative touching; she is bigger and hungrier than he is, and she may have a different definition of “romantic dinner.”  In any case, males don’t survive long after mating, and yes, she may eat him.  She produces and hides an egg sac that contains as many as 800 eggs and is almost as big as she is (see the series of pictures at https://bugguide.net/node/view/719111/bgimage), and she hangs around to guard it for the rest of her life.  The first killing frost finishes off any survivors (interestingly, Cross orbweavers have a two-year life cycle in Europe)

Scientists have, indeed, studied the heck out of Cross orbweavers.  They’ve looked at the complex business of web-building, at the factors that affect the placement/angle of the radius threads (spokes), at specifications for habitat selection, at the types/functions of hairs on the spiders’ legs, at the fact that urban spiders are larger than their rural relatives (the urban heat island effect), at the tensile strength of cocoon silk, and much more.  Be sure to check the web diagrams in this study https://www.sciencealert.com/spider-on-drugs, in which researchers dosed Cross orbweavers with a variety of substances – LSD, caffeine, pot, mescaline/peyote, and a few more (with a link to a longer NY Times article).

Fun Cross Spider Facts:

  • Cross orbweavers typically hang upside down at the center (hub) if their web.  Eric Eaton describes their behavior when alarmed, “The spiders themselves will literally shake at the close approach of a person or other large animal, vibrating their web and no doubt startling the inquisitive visitor. Should that tactic fail, most orb weavers drop abruptly from their web, anchoring a dragline to the hub so that they can climb back up once danger passes” (Bug Eric http://bugeric.blogspot.com/2011/08/spider-sunday-cross-spider.html).

  • Cross orbweavers are one of the best-known spiders in the world and in 2010 had the honor of being named “European Spider of the Year.”

  • Eric Eaton also tells us that ““Anita” and “Arabella” were two female Cross spiders that were sent into space in Skylab 3 in 1973 to study the effects of zero gravity on web construction.

Cross orbweavers are not aggressive and generally bite only if cornered or inadvertently grabbed.  Side effects of their bites are mild in most people (redness, swelling, pain) and last only a few days.

Kate Redmond, The BugLady

Bug of the Week archives:

Winter Camp 2018!












Do your kids miss summer camp and wish they had something exciting to do during winter break? We’ve got just the solution! Join us at Riveredge for our fourth annual Winter Camp!

Our beautiful 379 acres unveil a whole new world in winter. During our fun-filled days, we’ll hike, snowshoe, build campfires, create winter crafts, play awesome games and much more! Both indoor and outdoor activities are carefully planned based on the weather and led by our fun and fully trained camp staff!

It’s the perfect recipe for beating the winter doldrums (and saving mom and dad’s sanity during winter break).



What ages is this camp for? 

Winter camp is for campers aged 6-12. Once we have all our campers signed up, they will be divided into groups based on age, so you can be assured your child with be placed with an age-appropriate group!

What do campers need to bring? 

Once you’re signed up, you’ll get a full packet of info with everything you’ll need to know closer to the start of camp. But basically, enough layers and gear to be appropriately dressed for winter weather and a lunch. We’ll provide all the fun!

What time is camp? 

Camp is from 9 AM to 4 PM each day (Wednesday, Dec 26th to Friday, Dec 28), with an optional overnight option on Friday night (see below). Campers will need to be transported to and from Riveredge at those times each day.

What’s this overnight option about?

Campers will have the rare chance to experience Riveredge at night. Our camp staff will lead fun activities all evening, we’ll cook dinner over a campfire, and in the morning we’ll make pancakes with delicious Riveredge maple syrup. Don’t worry though, we’ll be sleeping inside! This Friday overnight is completely optional and participating campers will be need to be picked up at 9 AM on Saturday.

Do I have to sign up ahead of time?

Yes, please! Pre-registration is required and Winter Camp enrollment is limited and will be filled on a first-come, first served basis, so be sure to register as soon as possible!

What’s the cost?

Cost is $145 per camper for Riveredge members (not yet a member? Sign up here for huge discounts on camps, programs, special events, and much more!) or $160 per non-member child. The optional overnight add-on is $25 per child. (Pssst, have more than one child interested in attending camp? We offer a multiple child discount!  First registration is full price and each additional child will receive 10% off.)

Any other questions?

We’re happy to help answer them! Give our camp coordinator, Steff Merten, a call at 262-375-2715 or by email at smerten@riveredge.us

Cancellation Policy: Registrations may be cancelled up to 30 days prior to camp to receive a refund of registration fees minus a $50 non-refundable deposit. If you cancel less than 30 days before your week of camp, refunds are only given for medical reasons and family emergencies. These refunds are also subject to the $50 non-refundable deposit. 

Bug o’the Week – Trogus pennator

Salutations, BugFans,

The BugLady was walking along the trail at Forest Beach Migratory Preserve recently when she saw a flashy, orange, inch-long wasp actively hunting for something in some white ash saplings.  The wasp was flying from tree to tree, searching among the leaves.  It returned several times to a twig upon which sat an infant Tiger swallowtail caterpillar, and the BugLady feared that the wasp would grab the caterpillar to provision a brood cell; but it turned out that this was an Ichneumon wasp, and she had other plans for the caterpillar.

The wasp family Ichneumonidae is a huge one – at around 60,000 known species (and maybe another 40,000 undiscovered species waiting in the wings), it’s in contention with weevils and rove beetles for the title of Largest Animal Family.  Some 5,000 species of Ichneumons call North America home, and about them bugguide.net says, “Ichneumonids are notoriously hard to identifyaside from the sheer number of species, there are numerous cases of distant relatives that appear almost identical. Any identification based solely on comparing images should be treated as suspect unless an expert has said there are no lookalikes for the species or group in question.” Which puts the BugLady way out on that taxonomic limb again, but she’s gotten pretty comfy there.

Ichneumon larvae typically live as parasitoids in the bodies of other invertebrates, not delivering the coup de grace until it’s time to pupate (the wasp larva successfully; the host, not).  Ichneumons can be highly specific in their choice of hosts.

So, the orange wasp is (probably) Trogus pennator (no common name).  Here’s a nice picture of one: https://bugguide.net/node/view/961275/bgimage.  Trogus comes from a Greek word meaning “to gnaw” and pennatorfrom the Latin for “feather” or “wing.”  And yes, there is a look-alike, an unrelated spider wasp named Tachypompilus ferrugineus, but Tachypompilus has a smooth-ish abdomen https://bugguide.net/node/view/128288/bgimage, and Trogus’s abdomen has a “beaded” look.  It has been suggested that Trogus pennator mimics the spider wasp because spider wasps can sting (painfully), while the Kaufman Field Guide to Insects of North America, says of Trogus’s subfamily Ichneumoninae that “Females have venom glands and some can sting weakly.”  There are a dozen species in the genus, half of them in the New World.

Credit where credit’s due – a good deal of the work that has been done on Trogus pennator has been carried out by researcher Karen Sime of Cornell University (Go, Big Red!), who theorizes that the genus originated in the Palearctic region (the northern half of the Old World) and arrived in the New World via Alaska on the heels of the spectacular Old World Swallowtail butterfly https://bugguide.net/node/view/1199312/bgimage.

Why?  Follow the Food!  The larvae of Trogus wasps are (alas) parasitoids of the larvae of swallowtail butterflies.  Some species of Trogus are swallowtail generalists, and others are pickier, but they all avoid the caterpillars of the Pipevine swallowtail, whose host plant’s toxicity the caterpillars stockpile.  How do the wasps know?  They “sample” the caterpillar with their antennae, which alerts them to the presence of poisons.

So Ms. Wasp’s search was for swallowtail caterpillars, and a lot of research centers on exactly how she locates them.  It’s possible that the wasp can identify the host plants visually, and she may be able pick up on the chemical signature of undamaged leaves, but in one study, Trogus pennator wasps targeting Zebra swallowtail larvae were found to recognize the odor that a host leaf emits when it’s damaged by grazing caterpillars.  Once they’ve found caterpillars on them, “naive wasps” quickly learn their host plants.  After that, they don’t waste time on non-host plants, and they concentrate on host plants with damaged leaves.  But – think about it – does a wasp like Trogus pennator, which has more catholic tastes, learn to ID all of the host plants of Tiger Swallowtails (Butterflies of the North Woods lists about a dozen of them) plus the food plants of Black Swallowtails (here’s one that emerged from a Black Swallowtail chrysalis https://bugguide.net/node/view/395314), plus Zebra Swallowtails, plus….?



When she finds a caterpillar, Trogus pennator inserts a single egg into it (and the BugLady may have accidentally captured that moment).  The BugLady found a second caterpillar, in the open on the leaf of a nearby ash – it had a small, black “button” at the end of its abdomen, and the BugLady is wondering about that.  The caterpillar goes on its way, feeding and growing, but it’s a goner – only the wasp will exit the chrysalis.  If the swallowtail caterpillar is from the second brood, destined to overwinter as a chrysalis, the wasp larva goes into a state of diapause (suspended animation) along with it and emerges in spring.

Some swallowtails try to adapt – butterflies may lay eggs lower on host plants than the wasps typically hunt, and caterpillars may feed at night.

[Editorial Comment: She’s a beautiful wasp, and her behaviors are fascinating, and yes, she has to make a living, but Tiger Swallowtails?  Tiger Swallowtails are the BugLady’s favorite bug, and she’s worried about them.  They have two broods a year – the small spring flight is made up of survivors of the cohort of fall caterpillars that endured the rigors of winter as a chrysalis.  Their offspring pupate in the mild days of June and July and emerge as a mid-to-late summer brood that needs to be large, because of the hazards their offspring will face in the winter.  The spring numbers were respectable this year, but the wildflowers are waning, and the BugLady just hasn’t seen many second brood Tiger Swallowtails.  Some other phenological benchmarks seem a bit off kilter this summer, so maybe there’s still time.]

Kate Redmond, The BugLady 

P.S. – this seems timely: https://uwm.edu/field-station/the-mighty-mosquito/

Bug of the Week archives:


Bug o’the Week – More Scenes of Summer

Greetings, BugFans,

OK – it’s September, but the bug season isn’t over yet.

Outside of wetlands, if there’s anything better than a walk on the prairie, surrounded by Big Bluestem grass, with big Common Green Darners and Black Saddlebags dragonflies overhead, the BugLady hasn’t found it yet.  Here is another batch of summer images, mostly from prairies.

Look for the AMERICAN RUBYSPOT (one of our classiest damselflies) near running water.  Yes, the male is spectacular, but the female is no slouch, either.

American rubyspot male


American rubyspot female

ANT AND GRASSHOPPER – When Aesop wrote the fable about the grasshopper and the ant (you remember it – the ant prepares for tomorrow while the grasshopper fritters), this probably wasn’t what he had in mind.  The largish ant and the smallish grasshopper were going home for dinner together.

CAROLINA LOCUST – This is the large, very well camouflaged grasshopper/locust that jumps up in front of you as you walk in the prairie.  Its flying wings are inky, with cream-colored margins, reminiscent of a Mourning Cloak butterfly.  Males advertise for mates by hovering above the grass-tops and making a rattling/crackling/snapping/clicking sound (it’s called crepitation) with their wings.  It looks like it was carved out of stone.

BLACK SADDLEBAGS DRAGONFLY – Any day now, Black Saddlebags and Common Green Darners will set their course for the South and sail down the Lake Michigan coastline in a steady stream.  Only 15 of the 460+ species of dragonflies and damselflies migrate, and it’s a grand sight.  Local BugFans can watch from the bluffs at Lion’s Den Nature Preserve near Grafton as the dragonflies go past at eye level.

Mooned by JAPANESE BEETLES.  They’re having a good year this year.  These lusty scarabs were first seen in 1916 at a plant nursery in New Jersey, having arrived as hitchhikers in a shipment of iris bulbs from Asia.  They are the ultimate generalist herbivores, feeding on the leaves and fruits of about 300 different plant species, both woody and herbaceous.  Pretty, though.

MAYFLY – The BugLady was photographing an ambush bug with its prey when she felt something land ever-so-lightly on her arm.  If she’d have guessed before looking, she never would have guessed a mayfly.  Mayflies are in the well-named order Ephemerata, and ephemeral they are.  Their naiads live for a year under water, and when they emerge as adults, often in Biblical numbers, they are unequipped with mouthparts and live for only a few days.  But it’s enough.

BLACK AND YELLOW ARGIOPE – The BugLady is thrilled to see good numbers of these spectacular orbweavers this year.  They’re beautiful, and they’ve been hard to find lately.  Orbweavers are with us all summer, mostly unobserved until late August, when they reach an impressive size.

STINKBUG AND PREY – A (probably) Podisus maculiventris stinkbug nymph making a meal out of an alien Pine sawfly larva, on a porch rail; the duo probably dropped out of the White pine above.  They’re known as Spined soldier bugs because of the adults’ pointy “shoulders” https://bugguide.net/node/view/700220.  Stinkbugs insert their mouthparts into their prey, pump in the meat tenderizer, wait a bit, and then suck out their prey’s softened innards.

TIGER SWALLOWTAIL – The BugLady has a small flower garden at her new home, mostly populated by horticultural (“tame”) stuff that she’ll be replacing with native plants.  She may make an exception for this lily, which was both hummingbird and butterfly-friendly.

VICEROY and MONARCH – Telling a Monarch butterfly from a Viceroy is easy, once you know the secret handshake.  Viceroys are a bit smaller, and (to the BugLady’s eyes) their flight is a bit peppier than a Monarch’s, but those traits are pretty subjective.  The Viceroy is always held up as a Monarch mimic that cashes in on the fact that Monarchs are toxic because of their caterpillar’s food plant, and predators learn to avoid them.  Viceroy caterpillar host plants are willow, aspen, and poplar, and some scientists believe that while they may not be toxic, they are probably distasteful, and the two species complement each other https://uwm.edu/field-station/viceroy/.  Anyway, the Viceroy, on the left, has a C-shaped black line through the hind wing.

SYRPHID/HOVER/FLOWER FLIES – There have been astonishing numbers of these small, harmless, bee-mimicking flies in grasslands lately.  Swallows, dragonflies, damselflies and other consumers must be living large on them.

A MASS of MONARCHS – Monarchs migrate along the lakeshore, too.  The BugLady found two groups with about 50 Monarchs apiece – early migrants – tucking themselves in for the night at the end of her driveway one afternoon in mid-August.

Go outside.  Find a prairie.  Look at bugs.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Bumble Flower Beetle

Howdy, BugFans,

The BugLady had a wonderful Beetle Experience the other day.  She was at Riveredge Nature Center, attempting to photograph some butterflies (a Common Wood Nymph and a few Viceroys) on a large cup-plant that had bloomed and was forming seeds when she noticed s

ome drab, half-inch, hairy bees sitting on/in the flower heads.  When she took a closer look (and some pictures, of course), she discovered that they were a flower scarab called the Bumble Flower Beetle.

Bumble flower beetle and viceroy


Bumble flower beetle and wood nymph



(Blogger Dragonfly Woman got pretty excited, too, when she saw her first one: “It wasn’t a bee at all, but Euphoria, a fantastic scarab beetle! It tried to fly away when I picked it up, making a loud buzzing reminiscent of its namesake as it attempted to escape, but I snatched it out of the air and slipped it into my lunch bag to take it home to photograph. https://thedragonflywoman.com/2013/04/12/views-of-euphoria/.)

Flower scarabs are in the beetle family Scarabaeidae and the subfamily Cetoniinae.  As a group, the 4,000 or so flower scarabs/flower chafers are diurnal as adults, feeding on pollen and nectar (and providing pollination services while they’re at it), or on sap drips on injured plants, or on plant tissue, including fruit.  Their larvae are recyclers, mostly eating decaying vegetable material.

The larvae of some species in the subfamily grow up in ant hills, consuming the ants’ food stores while the ants inexplicably ignore them.  Adult beetles may live there, too, secreting a sweet liquid for the ants to eat while the beetles eat larval ants (fascinating back story – some adult beetles are “killed” by ants (they play dead) and are carried down into the nest).  A California species of Euphoria lives on the midden heaps in pack rat burrows.  See http://bugeric.blogspot.com/2015/04/anteater-scarab-beetles.html for an account of the lifestyle of a related beetle.

Some genus members run afoul of agriculturalists and are well-known to University Extension entomologists across their range, but a few may be taking the rap for other insects.

Anyway, the excellently-named Bumble Flower Beetle (Euphoria inda), also called the Brown Fruit Chafer and the Indian Cetonia, is one of 24 Euphorias in North America.  Here’s a glamour shot https://bugguide.net/node/view/987232/bgimage.  Its name comes from both its appearance and its behavior.  The beetles happily congregate, and they may fly around near the ground like bees.  While most beetles fly with their elytra (the hardened, protective front set of wings) extended, the chafers fly with elytra closed, producing a buzzy sound https://books.google.com/books?id=IhLZDgAAQBAJ&pg=PA40&lpg=PA40&dq=flower+chafer+beetles+closed+elytra&source=bl&ots=lpvDoVMBpV&sig=SWIAOqvVCZ0-RPXp8sxJaPKU1Zk&hl=en&sa=X&ved=2ahUKEwjX2oakk4fdAhXm8YMKHT-5BGc4ChDoATACegQICRAB#v=onepage&q=flower%20chafer%20beetles%20closed%20elytra&f=false).  It’s speculated that the two-winged mode may allow more agile flight.

Bumble flower beetles can be found in grasslands and gardens across the continent, feeding on fermenting sap, ripe/rotting fruit, flowers, pollen and nectar.  It’s believed that they take advantage of already-existing cracks and splits in fruits and of damage done by other insects and that they don’t spread plant diseases while feeding.

They are sometimes listed as minor corn pests.  Said F. M. Webster in his “Insects Affecting the Corn Crop” in the 1886 report of the Indiana Board of Agriculture, “The adult beetle has been accused of feeding upon the kernels of young corn in the fields, and Dr. Harris states that they sometimes feed upon the sap of the stalks in September.  Its depredations have so far been of minor importance, and, in fact, it is not altogether clear that the insect is guilty of making the first attack upon the corn, there seeming to be the strong probability that birds, particularly the English Sparrow, are the first depredators, the beetle only taking what is left.  I have observed black birds pecking the young ears of corn in the fall, leaving the milk oozing out of the kernels, and have no doubt that this would attract even innoxious insects.”

The BugLady’s beetles probably emerged as adults fairly recently and will be foraging through September.  They will overwinter as adults in the soil and resume their feeding (and breeding) in early spring (these beetles https://bugguide.net/node/view/727426/bgimage emerged in central Wisconsin at the end of March, in the bizarre, early spring of 2012).  Eggs are deposited near compost, soil, and manure piles, decaying wood, etc., and several sources said that Bumble flower beetles are among the species that will use ant nests.  Eric Eaton, in the Kaufman Field Guide to Insects of North America, says that their “Grubs have been found in the nests of ants,” so maybe it’s not a universal practice.  They pupate in a chamber they create underground.

Appearing to be a bumblebee helps keep predators away, and they’re pretty well camouflaged, and the beetles are also chemically defended, producing what is described as a “pungent chlorine-like odor.”

The BugLady was curious about the connection between the beetles and all the other insects feeding at the same trough.  Turns out that like the flower beetle, both species of butterflies come to fermenting fruit juices as readily as to flowers (and flies are, well, flies).  Whatever’s going on in those seed heads appeals to all.

Kate Redmond, The BugLady

Bug of the Week archives:

Bug o’the Week – Seven-spotted Ladybug

Greetings, BugFans,

Sometimes, the origins of insects’ names are pretty inscrutable, but not that of the Seven-spotted Ladybug.  Its name does need a little unpacking, though – like the firefly/lightning bug, the ladybug/ladybird is a beetle (alternate name, lady beetle).  The Lady in question is the Virgin, to whom the people in the Middle Ages prayed when aphids were devouring their crops, and who is said to have responded by sending this species of aphid-loving beetle.  In gratitude, people named them “the beetle of Our Lady,” a name that proved cumbersome and was shortened first to “Our lady’s beetle” and then to “lady beetle.”  According to one source, its seven spots symbolize Mary’s seven joys and seven sorrows.

Perceptive BugFans are thinking, “Wait a minute – didn’t the Middle Ages happen in Europe?  Is this another exotic beetle species?  Yes and yes.  Its historic range is Eurasia (it’s said to be the most common ladybug in Europe), but it was introduced to North America in the 1950’s (and the 1960’s and the 1970’s) as a biological control.  Now, it can be found wherever there are aphids, which means ag-lands, grasslands, gardens, open woodlands, marshes, etc.

The Seven-spotted ladybug (Coccinella septempunctata), family Coccinellidae, is one of about 5,000 species of ladybugs in the world.  Most species come on a pretty basic chassis with a variety of dots and dashes against a background that varies from yellow to pink to red to black, sometimes within the same species.

At 7 to 10 mm long (¼” or so) the SsL is one of our larger ladybugs.  As promised, it has seven spots distributed over its elytra (hard wing covers).  The number of spots can be diagnostic in ladybug species, except when it’s not – Multicolored Asian lady beetles may have zero spots or many, and “teneral” forms, newly-emerged beetles whose colors haven’t “set” yet, can be deceiving https://bugguide.net/node/view/898160/bgimage.

Thorax patterns may be more reliable.  For instance, no matter what color they are or how many spots they have, most Asian ladybugs have a “W” at the top of the thorax (or “M,” depending on which side of the beetle you’re standing on).  The BugLady’s favorite pattern is the Red ladybug https://bugguide.net/node/view/1301740/bgimage, with its curlicues.  There are two, white spots on the SsL’s face, and its thorax is mostly black, with the head framed by two white “squares.”  The large, black spot at the front of the elytra is bordered by a white “bowtie.”

In North America, booming populations of SsLs may be out-competing native ladybugs (they are considered by some to be invasive); while in England, where they’ve sometimes occurred in disconcertingly large swarms, SsL numbers have declined with the influx of the Harlequin/Multicolored Asian ladybug.  For the story of the infamous Asian ladybug, see https://uwm.edu/field-station/multicolored-asian-ladybug-family-coccinellidae/.

SsL’s are promiscuous, mating several times a day.  Females may lay eggs on aphid-rich vegetation immediately, or, in fall, may store sperm and lay eggs in spring so their larvae have a more robust food supply.  Adults overwinter in a state of diapause (dormancy) in leaf litter, dense vegetation, under tree bark, and in other sheltered spots, often with other SsLs (up to 200 of them) that they attract using pheromones (and when spring comes, it’s party time).

A female can detect the “odors” of eggs of other ladybug species and will avoid placing eggs in the wake of another female.  When it hatches, a larva eats its egg shell and any unhatched eggs of its siblings, and then starts in on aphids and other small invertebrates that it finds on the leaf’s surface (including, alas, monarch eggs and tiny caterpillars).  When they are small, they simply suck out their prey’s juices, but older larvae chew up the whole thing (ladybug larvae are always likened to tiny alligators).  Ladybugs are unusual among insects with complete metamorphosis (egg-larva-pupa-adult) because both the larvae and the adults occupy the same spaces and eat the same thing (in a pinch, adults may eat pollen and nectar, too).

Ladybug pupa

Several sources said that during its lifetime, a single SsL can put away as many as 5,000 aphids!  How do they find the aphids?  They pick up on the chemical traces emitted by plants that are being grazed by aphids, and they can also sense the alarm pheromones of the aphids themselves.

Ladybugs pupate right out there on the surface of the leaf; read about how they get away with it at https://uwm.edu/field-station/ladybugs-three/.

And speaking of “out in the open,” how does a brightly-colored beetle live in plain sight without getting eaten?  Like other ladybugs, SsLs release toxic/bad-tasting droplets from their leg joints when threatened (reflex bleeding).  So, their bright colors are aposematic (warning) coloration.  Despite that, they are eaten by other ladybugs and by a variety of spiders, birds, and small mammals, and they entertain many parasites.

For an informative, off-beat approach to ladybugs and some great pictures, see https://askentomologists.com/2018/03/12/ladybug-meme/.

FUN FACT ABOUT SSLS – they are the State Insect of five states.  The BugLady always thinks it’s a waste when State Insects are non-native (other categories, too – the State Birds of Delaware and Rhode Islands are chickens).  Wisconsin’s State Insect is the European honeybee https://en.wikipedia.org/wiki/List_of_U.S._state_insects.

Kate Redmond, The BugLady

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