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

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

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

Bug o’the Week – European Skipper Butterfly

Howdy, BugFans,   

The BugLady has trouble wrapping her head around the idea of a non-native butterfly, especially one that’s considered a pest.  What could be more benign than a butterfly?  But, there’s the non-native Cabbage White butterfly (there’s even an alien orchid that’s considered invasive in some areas – read https://northamericanorchidcenter.org/non-native-orchids/ for more about that).  Of course, when butterflies are listed as a pest species, it’s because of the dining habits of their caterpillars.

European Skippers (Thymelicus lineola) fetched up on these shores (London, Ontario, to be exact) in 1910 – one source speculated that the eggs were carried in the seed heads of the also-alien timothy grass, possibly in dried grass that was being used, pre-“plastic peanuts,” to cushion a shipment of ceramics (a common practice in by-gone days and one that brought other alien grasses from the Old Country).  The ES has been expanding its range ever since, both under its own power and as eggs transported in hay (in a study of hay bales, researchers found more than 5,000 ES eggs in a single bale of timothy hay, and another source referenced a range map for ESs and said that if it was more than two years old, it was out of date).

They are a “cool-climate” butterfly that ranges across Canada and the northern tier of states (largely skipping the Great Plains), and throughout the Northeast, and they’re found in all sorts of grasslands, plus parks, gardens, roadsides, and wetland edges.  They are common within that range, sometimes mind-bogglingly so.  According to the wisconsinbutterflies.org website (https://wisconsinbutterflies.org/butterfly), “This species is most impressive for its occasional abundance, far greater than that of other skippers in the northern states. The record high for this species on a single North American Butterfly Association count is 55,340 and every year the highest count is well into the thousands.”  Bugguide.net says that “It is becoming the most common skipper and considered a threat to Polites peckius” [Peck’s skipper].

European Skippers are in the Skipper family Hesperiidae and in the Grass skipper subfamily Hesperiinae.  Adult Grass skippers tend to perch on flowers with their wings slightly “ajar” – the forewings held closer together than the hind wings (which can make seeing the color patterns tricky) – and the host plants of their caterpillars are mostly grasses and sedges.  The caterpillars may web a few grass leaves together as a shelter and feed nocturnally.  On the other side of the Pond, European Skippers are called Essex Skippers.

They’re a smallish butterfly with a wingspread of 1 to 1 ½ inches and the typical chubby, hairy body of a skipper.  Like many grass skippers, they are orange and brown, but orange (one site describes it as “pumpkin orange”) predominates both on the upper and lower surfaces of the ES’s wings.

ES caterpillars eat timothy grass and, to a lesser extent, a few other exotic grasses.  Timothy, a sun-loving grass whose seed heads look like mini-cattails, came over on the boat from England, too, probably before 1700, as a contaminant in other plant materials.  The settlers here recognized it as a good livestock food and started cultivating it (England caught on later), and it continues to be important horse and cattle fodder today (it’s also sold as food for pet rabbits and rodents).  It’s named after a farmer named Timothy Hanson, who played Johnny Appleseed by spreading the grass from New England to the mid-Atlantic coast by 1747.  It’s sometimes planted as a soil holder in road construction.

The caterpillar damages timothy grass by its feeding, sometimes stripping the leaves of a plant, and when a lot of caterpillars are present, by eating the seed head, too, leaving a bare stalk.  According to a slightly-dated entry on the Canadian Biodiversity Information website, “Even after almost a century it seems that native parasites have not yet developed a ‘taste’ for this species” (although a naturally-occurring virus can be lethal to them and is being considered where caterpillar control is needed).  Adults nectar during the day on a variety of composites (fleabane, thistle), clovers and other mid-summer wildflowers.

Males patrol, close to the ground, searching for mates.  Females lay as many as 30 pale green eggs, in strands of three or four each, on grass leaves or seed heads.  Alone among all of the 275 species of North American skippers, ES’s overwinter as eggs, and the caterpillars emerge in spring.  Here’s a caterpillar, https://bugguide.net/node/view/294788/bgimage, and here’s a pupa https://bugguide.net/node/view/124322/bgimage.

Adults tend to sit out very hot or cloudy weather, and they spend the night perched down in the grass.

Speaking of orchids, the BugLady found an interesting paper about the effects that foraging ESs have on seed production in the spectacular Showy Lady’s-slipper orchid.  Orchids are famous for the tricks they play on potential pollinators and the hoops they put them through.  A number of orchids are pollinated by “naïve bumblebees” (a term that tickles the BugLady).  The orchids advertise their flowers by odor or color; the bees enter, and they find no nectar reward, but they leave bearing pollen.  It takes a few unrewarding visits before an individual figures it out and moves on to more rewarding flower species, but there are always more naïve bumblebees out there.

In the case of Showy lady’s slippers, pollinators are lured into the slipper and are trapped in it because the tissue around the lip’s opening is folded into the flower.  The only way out requires them to squeeze past hairy structures that first relieve them of any pollen they are carrying and then deposit new pollen on them before they reach the narrow exit – with no nectar for their efforts.

In one study, the majority of Showy lady’s slipper flowers in a study bog in Ontario contained one or more dead ESs, which can’t escape by the normal routes (one flower held seven!).  Males outnumbered females, because male ESs emerge from their chrysalis earlier than females.  Once an ES gets into the flower, pollination by the normal pollinators – leaf-cutter bees, syrphid flies, and a few small beetles – becomes difficult-to-impossible and seed production plummets.  If the ES can’t escape, like the naïve bumblebees, it can’t learn to bypass the orchid.

So – rising populations of ES have the potential to impact Showy Lady’s slipper populations https://www.researchgate.net/publication/318441873_European_Skipper_Butterfly_Thymelicus_lineola_Associated_with_Reduced_Seed_Development_of_Showy_Lady’s-slipper_Orchid_Cypripedium_reginae.

Kate Redmond, The BugLady 

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

Bug o’the Week – Summer Survey

Greetings, BugFans,

The BugLady is spending as much time as she can in the field (and the rest of it editing pictures) because, you know, the Summer Solstice has passed, and a little wave of warblers moved through her yard the other day, and winter is coming.  Many of these beauties have already starred in their own BOTW.  In a nutshell – there’s a whole lot of romance in the air.

CICADAS are calling https://uwm.edu/field-station/dogday-cicada-family-cicadidae/.  Historically, we’ve had lots of Dog-day cicadas in Southeastern Wisconsin (and very few of the famous Periodical cicadas), but there are other voices, too.  Along the Mississippi, some species sing well into the night.  The BugLady Googled “Cicadas Wisconsin” and found this nifty site: http://www.cicadamania.com/genera/usa.php?category=A&qs=WI

JAGGED AMBUSH BUGS (a common name shared by about 20 species in the genus Phymata) are pretty high on the BugLady’s list of favorites. They are fierce predators with a lot of attitude wrapped up in that little body.  When the BugLady sees an inert (and sometimes sizeable) insect dangling from a plant, the predator at the other end is inevitably a crab spider or an ambush bug.

When the BugLady is editing ambush bug pictures, she often discovers a well-camouflaged second ambush bug, or even a ménage a trois in a flower.  Bugguide.net tells us that “Coupling may involve several males riding around on a single female. Sometimes it allows them to take down larger prey, although coupling individuals have been found each with their own prey as well.”

ANTS CARING FOR TREEHOPPERS – Some species of ants (and wasps and bees and other insects) supplement their diet with honeydew, a sugary liquid that comes out of one end of an aphid or treehopper when it takes in plant sap (which comes out under pressure) through the other end.  Ants “farm” the honeydew producers, protecting them from predators, and in return they are allowed to “milk” their “livestock.” Win-win.  Animals (and plants) that have symbiotic relationships with ants are called myrmecophiles.

It’s BLISTER BEETLE season.  Black blister beetles (Epicauta pennsylvanica) conspicuously prowl the goldenrods in August.  These elegant gray and black beetles are members of the Epicauta cinerea group, which includes six, very similar species north of the Rio Grande that can be gray and black, or all gray, or all black.  The BugLady suspects that these are Clematis blister beetles (Epicauta cinerea), because they were crawling around on Virgin’s Bower vines.  The first stage/instar larva of many blister beetle species is a “larva on steroids” called a triungulin – a very mobile critter that actively searches for its food.  When it locates prey, it settles down as a normal, sedentary grub.  Members of this genus eat the eggs of many grasshopper species.  Look, but don’t touch: https://uwm.edu/field-station/blister-beetle/.

Some blister beetles have an elaborate courtship – as the BugLady watched this pair, the male advanced from the rear, rocking back and forth, twirling his antennae and maxillary palps (paired appendages below the mandibles, used for sensory and feeding purposes).

This TULE BLUET is carrying quite a load of water mite nymphs on its abdomen.  Like their tick relatives, the mites feed from the outside of the dragonfly.  They climb on board an almost-mature dragonfly or damselfly naiad while it is still under water, but they don’t feed.  When the adult pulls out of its old exoskeleton, they attach themselves anew while it is resting and its new exoskeleton is still soft.  A big mite load can sap the insect’s energy, shorten its life, and, depending on where they’re attached, even interfere with reproduction.  For a good article about mites, see: http://nwdragonflier.blogspot.com/2012/01/mite-y-dragons-odonata-and-water-mites.html

CRAB SPIDERS are masters of camouflage, with the ability to change their color from yellow to white, and back.  It takes up to three weeks to go from white to yellow, but only about a week to turn from yellow to white.  Why?  Because the yellow pigment has to be produced, but to go back to white, the pigment just has to be reabsorbed and excreted.

They don’t spin “trap webs” like the orb weavers, but they’re not above creating a little shelter, and this one webbed some ray flowers together for a bit of extra camouflage.  Pollinators beware!

PHANTOM CRANE FLIES are about as magical as it gets.  They are a subtle movement flickering at the corner of your eye on the dappled edges of wetlands – like those stars at night that you can only see by looking slightly to the side.  Slim, leggy flies, they fly/drift through vegetation, aided by ridges on their tibiae that catch the breeze like tiny sails https://uwm.edu/field-station/phantom-crane-fly/.

It’s hard to connect this LACEWING LARVA with the delicate, golden-eyed adult Green lacewing.  The BugLady started to write a brief bio about lacewings, and then she found this great video: https://www.youtube.com/watch?NR=1&v=fbRK6E5crbg&feature=endscreen.  Lacewing larvae like to drop out of trees onto the BugLady and bite her.  Wikipedia tells us that “the larvae may also occasionally bite humans, possibly out of either aggression or hunger.”  Definitely aggression.

GREAT BLACK WASPS are impressive wasps that dominate the flower tops in the second half of summer (there are a few species of blue-black mud wasps that look similar but are smaller).  If you look closely at her legs, you can see golden fringes near her feet.  Those are milkweed pollinia, sticky, saddlebag-shaped structures that are found within the flowers.  The BugLady sometimes finds lesser Hymenopterans, like honeybees, suspended from flowers when one foot gets stuck to a pollinium (she takes a grass stem and detaches them) https://uwm.edu/field-station/great-black-wasp/

WHITE-LINED SPHINX MOTHS have big population booms periodically – the last one was in 2013, and they were everywhere.  The BugLady was watching some hummingbirds squabbling over a patch of Bouncing Bet late one afternoon and she realized that one was smaller than the rest https://uwm.edu/field-station/white-lined-sphinx-moth/.  Yeah – a little out-of-focus – working on it.  Be on the lookout.

TREE CRICKETS are starting to sing https://uwm.edu/field-station/tree-crickets/, though this one is a bit too young to join the chorus.  Hear the full line-up at http://entomology.ifas.ufl.edu/walker/buzz/cricklist.htm.

Like other Odonates (damselflies and dragonflies) the male STREAM BLUET initiates this dance by transferring sperm from the tip of his abdomen to a receptacle neat its base.  When he grasps a female in back of her head (not a totally benign process – the BugLady has pictures of Spreadwing damselflies with bits of tissue stuck to their claspers/cerci), the female reaches forward and retrieves it, forming a “mating wheel.”  Later, he will guard her as she oviposits, to keep her from being stolen by a rival male.

And finally, what is summer all about, if not Technicolor, as illustrated by this VICEROY BUTTERFLY sitting on a prairie dock leaf?

GO outside – look at bugs (while ye may)!

Kate Redmond, The BugLady

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

Bug o’the Week – Red-shouldered Pine Borer

Howdy, BugFans,

Meet another of the BugLady’s new neighbors, a handsome black beetle with red epaulets called the Red-shouldered Pine Borer.  It came to her front door – well, actually, it was trapped in her front door, between the screen and the raised glass of the storm door, and its rescue involved dismantling the glass/screen assembly with one hand while holding a jar beneath the beetle with the other (empty flip-top Parmesan cheese containers make excellent bug jars).  Five days later, it happened again, with the appearance of the red individual.

Red-shouldered Pine Borers are in the Long-horned beetle family Cerambycidae, so named because of their long antennae, antennae that make them favorites of entomologists (and collectors) everywhere.  Some have spectacular antennae indeed https://blogs.massaudubon.org/yourgreatoutdoors/have-you-seen-this-beetle/ (click to enlarge the picture of this extremely threatening beetle).  Cerambycidae (from the Greek kerambex – beetle – and keras – horn) is a large family with about 30,000 species worldwide and just under 1,000 in North America.

They are in the Flower longhorn subfamily Lepturinae, a group known for their, slim, sometimes-exaggerated wedge shapes and their habit of visiting flowers by day (they like “flat” flowers like Queen Anne’s lace rather than deep, tubular ones).  There is only one species in the genus Stictoleptura in the New World, and it’s divided into three subspecies distributed across a big chunk of North America except for the Southeast.  In his book Beetles of Eastern North America, Evans describes the range of our subspecies, Stictoleptura canadensis canadensis, as Newfoundland to Pennsylvania west to Ontario and Minnesota.

The elytra (hard wing covers) of RsPBs come in a variety of colors including all red, all black https://bugguide.net/node/view/371891/bgimage, and almost all black https://bugguide.net/node/view/998834/bgimage.  Bugguide.net tells us that the first individual that the BugLady found is unusual because its antennae were black, not banded; the second (red) beetle had a few pale bands on its antennae, but the bands can be pretty noticeable https://bugguide.net/node/view/26315/bgimage.

Another name for the Cerambycids is the Round-headed borers.  As you might guess from those long, breakable antennae, it’s the larvae that earn the “borer” label.  In general, Cerambycids may live from one to three years, mostly in the larval stage, and in general, the larvae don’t kill trees, they tunnel in and initiate the breakdown and recycling of stressed trees and dead and decaying wood (except for prairie species, which feed in plant roots).  Larvae of the RsPB are found in fir, pine, and hemlock.

Adult Cerambycids may eat sap, fruit, leaves, pollen, nectar, and fungi.  Any arthropod that crawls across flowers is, by default, a pollinator, but the RsPB is probably not an important one.  In reference to beetles’ contribution to pollination, the BugLady was tickled to learn the term “mess and soil pollinators.”  According to the US Forest Service, “Beetles were among the first insects to visit flowers and they remain essential pollinators today. They are especially important pollinators for ancient species such as magnolias and spicebush. Beetles will eat their way through petals and other floral parts. They even defecate within flowers, earning them the nickname “mess and soil” pollinators.

(The beetles she found were on the inside, looking out, and the BugLady is hoping that’s because the door is porous, and not that the cedar walls of the cottage will soon be toast.)

Alas, the Wikipedia write-up of the RsPB is not a shining example of crowd-sourcing https://en.wikipedia.org/wiki/Stictoleptura_canadensis.  It’s a very brief and general account of the whole family Cerambycidae, not of the species; it reads like a bad translation, and it was subsequently cut and pasted unquestioned by a number of other legitimate internet sources like inaturalist.  Caveat emptor.

Kate Redmond, The BugLady

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

Bug o’the Week – Gold-and-Brown Rove beetle

Salutations, BugFans,

This is National Moth Week – find a celebration near you.

July is turning out to be Beetle Month, and here’s a beauty.  It’s a Rove beetle, family Staphylinidae, a beetle family that rivals the weevils (and the Ichneumonid wasps) for the title of largest animal family (and scientists are still discovering new species).  It will lose its place if a proposal to divide the Staphylinidae into four families gains traction.

Anyway – the Rove beetle family is varied in size, color, diet, and habitat.  In general they are mostly drab beetles with truncated elytra that nevertheless shelter a pair of flying wings folded together like a tiny work of Origami.  Most are carnivores or scavengers, and most carry on their lives out of sight.  Over the past 200,000 millennia, various Rove beetle species have adapted to live on tidal beaches and wetland edges, and in moist microclimates under rocks and loose bark, in fungi, manure, caves, burrows, and leaf litter, as inquilines (borders) in the nests of ants and termites, and as pest controls (eating flea and fly larvae) in the nests of some tortoises, birds, and mammals.  And more.  Some are dramatically chemically defended (and some of the inquiline beetles deploy “appeasement” chemicals).

See http://entnemdept.ufl.edu/creatures/misc/beetles/rove_beetles.htm for a good general biography of Rove beetles.

Scenic Side Trip:  The University of Florida article mentions that among the places that rove beetles may cohabit are “communal nests of butterflies in Central America.” (Entomological) Social butterflies?  Yes – caterpillars of the Madrone/Mexican butterfly (Eucheira socialis) in the family Pieridae (Whites and Sulphurs) are gregarious.  And (a little lagniappe) according to the very readable and prolific Gilbert Waldbauer in Fireflies, Honey and Silk, “The silken walls of a tent, a communal nest, constructed by one hundred or more cooperating Mexican butterfly caterpillars (Eucheira socialis) have served as a unique writing surface in both prehistoric and historic times.  Eucheira is one of an extremely small number of gregarious nest-building butterflies, but there are many such gregarious species among the closely-related moths… ‘The Aztecs,’ notes Richard Peigler, ‘called [this] insect xiquipilchiuhpapalotla, which means butterfly that makes a pouch.’  He describes the walls of the tent as resembling parchment paper in texture and color and being so tightly woven and tough that they could only be cut with a sharp knife.  These silken sheets were used as writing paper in Mexico at the time of the Spanish conquest.”

We have visited rove beetles before in the form of the Hairy rove beetle, the rusty-tailed Platydracus and the amazing Shoreline rove beetle https://uwm.edu/field-station/shoreline-rove-beetle-family-staphylinidae/.

According to bugguide.net, there are at least 30 described species in the genus Ontholestes, only two of which live in North America, and only one of which is native.  The name comes from the Greek onthos(“dung”) and lestes (“robber” or “pirate”).  The Gold and Brown Rove Beetle (Ontholestes cingulatus) is native, and it can be found in the northwestern and eastern US and across Canada, often associated with fungi, decaying organic material, and dung piles, but it’s also found in grasslands and is considered an indicator of undisturbed forests.

At first glance, GaBRBs might be mistaken for fireflies because of the iridescent yellow hairs (setae) on the thorax and abdomen, but it’s not bioluminescent – it doesn’t have the equipment. The “glow” depends on the angle you view it from, and one author suggests that it warns predators about the beetle’s potential for chemical warfare.  Here’s a much better picture than the BugLady’s – https://bugguide.net/node/view/188718/bgimage, and the BugLady rarely sends BugFans to commercial photo sites, but these are beautiful pictures: http://www.cirrusimage.com/beetles_rove_o_cingulatus.htm.  In one of the BugLady’s pictures of the GaBRB, the wings are fully extended along the abdomen, and in the other, they are almost completely concealed.

The adult is about ¾” long, and the larva is about an inch – on the large side for Rove beetles – with impressive mandibles https://bugguide.net/node/view/199498/bgimage.  When alarmed, adults run around with the tip of their abdomen raised in a threatening fashion, like a scorpion.

After mating, GaBRB males guard females as they oviposit near fungi or carrion or other decomposing organic material.  Guarding takes the form of, at least, blocking a rival’s advance, but the encounter may escalate to frantic circling of the female by the two males and, at worst, to wrestling/biting.  Females are relatively scarce, and interloper males will take advantage of the fact that she may still be receptive, and the fact is, the majority of the offspring are likely to be sired by the most recent male.  The larvae feed on carrion or fungi, and the adults eat the inevitable flies, maggots, and larvae of other beetles that are found those habitats.  The larvae pupate in chambers in whatever substrate they’re in.

(it’s happened again – Spellcheck has informed the BugLady that her 113 page working document of partially-researched upcoming BOTWs has too many misspelled words and grammar errors, the result of much cutting and pasting and lots of scientific and author names.  Consequently, all spell-checking will cease until she fixes the whole document.  Apparently, it’s the boss of her.)

Kate Redmond, The BugLady

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

Bug o’the Week – Thistle-head Weevil

Greetings, BugFans,

Another week, another alien beetle eating an alien thistle.  The BugLady found this pair of weevils while she was chasing Thistle tortoise beetles (clearly, it’s a weevil that gets a lot of mileage out of its food plant).  And, in the “Ain’t the Internet Grand” category, a Google search for “weevil on thistle” resulted in a quick ID.

It’s a small weevil in the Snout/Bark beetle family Curculionidae.  To put things in perspective, with 400,000 species and counting, the beetle Order Coleoptera is the largest Order in Class Insecta (in fact, beetles are the largest Order of animals, period, accounting for a quarter of animal species).  Curculionidae (70,000 species) is the largest beetle family and one of the largest animal families.

It’s a small weevil with some big names – the Thistle Head Weevil and the Nodding Thistle Receptacle Beetle (NTRB) (Wikipedia defines “receptacle” as “the thickened part of a stem (pedicel) from which the flower organs grow”). Like the Thistle tortoise beetle, of very recent BOTW fame, the Nodding Thistle Receptacle Beetle (Rhinocyllus conicus) is not originally from these parts; it hails from Eurasia and North Africa.  It was introduced to control the alien and invasive Nodding/Musk/Russian thistle (Carduus nutans) and a few of its relatives, and now it’s at home in pastures and grasslands and road edges over much of North America.

 

NTRBs are about a quarter of an inch long and have a fairly short snout.  They are dark/black in color, but freshly-emerged individuals are mottled with a coat of short black and yellowish hairs that makes them look like they’re dusted with pollen.  The hairs wear off over time, leaving the beetle bald https://bugguide.net/node/view/1374096/bgimage

In early summer, beetles congregate, and boy meets girl.  Females lay between 100 and 200 eggs, two to five at a time, on the bracts of the developing thistle flower buds https://bugguide.net/node/view/487333/bgimage, and then top each egg with frass (bug poop) (alternatively, some sources say she caps the eggs with chewed-up plant material).  The cap dries and protects the eggs from predators, and one source said that the cap attracts ants, which care for the eggs.  Newly-hatched larvae dive into the flower head where, according to Wikipedia, they feed inside the receptacle on flower parts and developing seeds – one larva may consume as many as 25 seeds.  The plant reacts like a gall, growing tasty tissue around them, which the larvae also eat.  Despite their secretive lifestyle, the larvae are found by parasitoids.

As they feed, frass that collects inside the flower head is mixed with masticated plant material to form a stiff chamber that becomes the pupal case.  Flower heads contain multiple larvae, and the combined pupal chambers may form a large, hard mass.  After pupation, the newly-minted adult lingers in its protective case for a while before exiting the flower.  Adults may chew on the leaves a little, but the larvae do the most damage.  NTRBs overwinter as adults and emerge early in the following summer to lay eggs and then die.  They are strong, diurnal flyers, but they are reclusive when they’re not feeding.

Biological control can be a “Be careful what you wish for” scenerio, and we are getting better at it, but the BugLady worries that at the base of any bio-control decision, there’s a value judgement about acceptable collateral damages.  The main story about this weevil revolves around its use to control Russian thistle, Milk thistle (Silybum sp.) and some non-native members of the genus Cirsium.  After an introduction to Canada was deemed successful in 1968, NTRBs were released in Virginia, California, Montana and Nebraska in 1969.  On some sites, thistle populations decreased by 80% to 95% in just a few years, and over the next few decades, weevils were deployed in most of the Lower 48.  They traveled to New Zealand in 1973, to Argentina in 1980, and to Australia in 1989.

It was assumed that the weevil would stick to its non-native targets, but by the mid-‘90’s, it was obvious that the NTRBs weren’t limiting themselves to exotic thistles.  While they specialize on thistles in the genus Carduus, a lot depends on synchrony – lining up their reproductive schedule with the budding of the plants.  At the edges of Russian thistle’s range, and when Russian thistle has finished blooming, the weevil showed a willingness to move to native thistles – in fact, it has been found in 22 of our 60-ish species of native Cirsium, some of them already rare.

(Remember – native thistles support a large and complex community of animals, from cohabitants of the thistle bud, to Goldfinches and small mammals that use the fluff for nests, to butterflies and native bees that eat pollen and nectar from the flowers, to bee keepers who bottle thistle honey, to herbalists who harvest thistles for their medicinal value.)

Apparently, other continents don’t have susceptible native thistle species, so North America is the only place where the NTRB is behaving badly.  It is now listed as invasive itself in several states and is barred from interstate shipment.

In a paper called “Rhinocyllus conicus – Insights to Improve Predictability and Minimize Risk of Biological Control of Weeds“(1999) S. M. Louda discusses the history and reality of this “experiment” [the BugLady’s word] and makes recommendations about future introductions.  He says:

Hindsight now demonstrates that, although the logic and reasoning were clear, the conclusion that Rhinocyllus was unlikely to have any major ecological effects was incorrect. The case suggests that more information was needed in order to make an accurate prediction.”

There is enough evidence to suggest that this biological control agent should not be moved into the region surrounding the Great Lakes [Too late – there were several local releases in Wisconsin in the early 1980’s, and the weevil was documented on a native a Cirsium about 20 years later, 80 miles from a release site].

Perhaps most damning: “So, the weevil was released into Canada in 1968, and into the USA in 1969, after exploration and initial testing in Europe. And, research on its biology and interactions was done once it was brought into North America” [emphasis, the BugLady].

A review of information on the release of Rhinocyllus conicus to control of Carduus spp. thistles in North America suggests at least 8 lessons for future biological control efforts. (See https://www.invasive.org/publications/xsymposium/proceed/02pg187.pdf).

In the words of the Germans/Dutch/Pennsylvania Dutch/Scandinavians (lots of people claim this saying), “We grow too soon old and too late smart” (or, in the words of Benjamin Franklin – “Life’s tragedy is that we get old too soon and wise too late.”).  Not a luxury we can afford, ecologically.

By the BugLady’s (admittedly quixotic) method of counting, this is (drumroll) Episode #500 in the series!  What a journey!  (Founding BugFans – you’re getting old!)

Kate Redmond, The BugLady

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

Bug o’the Week – Thistle Tortoise Beetle

Salutations, BugFans,

The BugLady was wandering the trails at Forest Beach Migratory Preserve recently when she spied a lovely green Thistle tortoise beetle on Canada thistle.  Tortoise beetles have made previous BOTW appearances in the form of the Mottled tortoise beetle (http://uwm.edu/field-station/tortoise-beetle/) in 2014 and the Horsemint tortoise beetle (http://uwm.edu/field-station/horsemint-tortoise-beetle/) in 2016.  After she saw an adult, the BugLady started looking for larvae on some of the scruffier-looking plants.

Thistle tortoise beetles are in the huge Leaf beetle family, Chrysomelidae (possibly 60,000 species worldwide), and in the Tortoise beetle subfamily Cassidinae (about 3000 species).  They owe their tortoise-like appearance to flared edges of the head, thorax, and elytra (although unlike a tortoise, the front and rear ends of the “shell” aren’t fused https://bugguide.net/node/view/940106/bgimage).  The beetle’s shape allows it to squat right on the leaf’s surface, which protects its underpinnings from ants, and because it melds seamlessly with the leaf, it’s less likely to cast a shadow for predators to see.

Some tortoise beetles are brilliantly-colored https://en.wikipedia.org/wiki/Imperial_tortoise_beetle#/media/File:Imperial_tortoise_beetle.jpg and https://commons.wikimedia.org/wiki/File:Desmonota.variolosa.jpg – so striking that, according to Brittanica.com, a few are used to make jewelry.  Our native Golden tortoise beetle can change colors – not through a trick of physics, like the Dogbane leaf beetle of previous BOTW fame http://uwm.edu/field-station/dogbane-leaf-beetle-revisited/, but intentionally (“emotionally”): https://blogs.scientificamerican.com/running-ponies/glad-you-ditched-the-anal-fork-golden-tortoise-beetle/.

Chrysomelids are vegetarians – some specializing on just a few plant species, and some considered agricultural pests.

The aptly-named THISTLE TORTOISE BEETLE (Cassida rubiginosa) is also called the Green thistle beetle and the Thistle-defoliating beetle.  And the Bloody-nosed beetle – according to bugguide.net, the Latin rubiginosus means “rusty/rust-colored” and “refers to the beetle’s ability to secrete a reddish liquid from its head” (a phrase that was repeated verbatim in lots of sources but elaborated on by none of them.  A defensive cocktail?).  The spines that poke out from around the larval body are called “scoli” and are sensory organs – like the bumpers on a bumper car, they tell the larva when something brushes against it (which makes the larva hunker down on the leaf surface).

Thistle tortoise beetles are not native to these parts.  In the Old Country, they are found throughout the Continent and across northern Russia.  They were first observed in Quebec in 1901, and they spread out from there and are now ensconced in grasslands, Ag lands, and disturbed/neglected open areas across the northern part of North America (and they were intentionally introduced to Virginia).

With a few (major) exceptions, their story is similar to that of many other leaf beetles.  A female deposits her eggs, about three at a time.  In this case, they are placed on the undersides of leaves in small packets https://bugguide.net/node/view/1034057/bgimage called oöthecae.  She takes her time, ovipositing in fits and starts with sizeable time-outs in between, for a total of up to 1,000 eggs.  Before she walks away from each egg packet, she covers it with a “secretion” and smears feces over it, which discourages predators and increases the eggs’ chances of hatching.

There is one generation a year, but because the adults overwinter in soil or leaf litter and emerge in spring, and because a female may lay eggs for three months or more, and because the larvae pupate and emerge as adults the same summer and keep on eating until it’s time to tuck in for the winter (they eat knapweed and burdock, too), you can find adults and larvae abroad for much of the growing season.  Adult feeding is superficial but the leaf-skeletonizing larvae really dig in; the “window pane” appearance of the leaf is characteristic.

Here’s a pupal case – https://bugguide.net/node/view/960322/bgimage – a number of the pupal cases that the BugLady photographed were broken open at the front, where the adult had emerged.

Canada thistles aren’t from these parts, either, but they’ve lived here since the 1600’s.  Like the beetle, Canada thistle is native to northern Asia and Europe (it’s called Creeping thistle in England), so in this case, both the pest plant and one of its grazers have accidentally made it to our shores.  Thistle tortoise beetles are crazy about Canada thistles and have been introduced as a biological control in New Zealand, a country that is extremely cautious about opening its borders to exotic plants and animals (in New Zealand they call it California thistle).

Can you order up a bushel of them to take care of your Canada thistles?  You cannot.  Says the Integrated Weed Control Project at Washington State University, “This insect is known to attack native thistles, is not an approved agent, and is NOT distributed by IWCP.”  For a couple of “shout-outs” for native thistles, see https://xerces.org/wp-content/uploads/2016/10/2016-029_Native-Thistle-Conservation-Guidelines_FINAL_web.pdf and https://weedwise.conservationdistrict.org/2017/thistle-identification.html.

Interesting Tortoise Beetle Fact #1: What is that dark, dampish glob, anyway?

Apparently, the larva never throws anything away.  Instead of dropping off each time the larva molts, the old skin is stored on twin forks protruding from its aft section.  And each time it poops, the frass (bug poop) is also conserved on those caudal/anal forks.  So – skin-frass-frass-frass, skin-frass-frass-frass – repeat as necessary – the compressed and portable scrapbook of its life https://bugguide.net/node/view/1238110/bgimage and https://bugguide.net/node/view/249152/bgimage.

Why?  The “stercoraceous parasol“(1869), “faeces pack” (1915), “frass mask” (1935) or “fecal shield” (today) has long intrigued naturalists.  An early theory about it being a tiny umbrella has been rejected.  It effectively disguises its bearer as an inanimate blob of bug droppings, and many predators avoid droppings because they are unsanitary health risks.  Add to that the fact that some species of tortoise beetles eat plants that are chemically defended, and so are toxic.  And, add to that the fact that the larvae can wave the mass of stuff around in a threatening manner, as several did while the BugLady was photographing them.  It’s not foolproof – spiders and some insects like stinkbugs and damsel bugs can pierce it.

Interesting Tortoise Beetle Fact #2: And it’s a lot to digest!

Humans can’t digest cellulose, the main structural ingredient of a plant cell wall, because we lack the necessary enzymes to do so (and so it travels through our systems as roughage).  Some herbivores produce the necessary enzymes, and others outsource the job to micro-organisms like bacteria.  The Thistle tortoise beetle has developed quite a complex process.

It has the enzymes needed to digest cellulose but lacks the ability to break down another important component of a plant cell wall – pectin.  But – it hosts free-living bacteria that are found in special sacs in the beetle’s gut, bacteria that provide enzymes that the beetle uses to break down pectin.  With the help of the bacteria, the beetles can access the nutrients in plant cells; within the shelter of the beetle, the bacteria can afford to simplify and streamline its genome.  Win-Win.  https://www.sciencedaily.com/releases/2017/11/171116132757.htm.  Mom passes the bacteria along by applying a coating to the cap of each egg shell, which the larvae eat after hatching.

Interesting Tortoise Beetle Fact #3:  Medical devices R US

Hmmm – how to explain this delicately so that the corporate filters don’t block this episode.  OK – the female’s reproductive system is a long and winding road, and the male has adapted quite adequately.  So well, in fact, that your next catheter may be modeled on the organs of the Thistle tortoise beetle.  The popular press was all over it:  https://www.npr.org/sections/thetwo-way/2017/12/20/571934373/beetle-penises-may-hold-clues-for-better-medical-devices.

And yes, they do look like tiny trilobites http://mentalfloss.com/article/68881/10-terrific-facts-about-trilobites.

 

Kate Redmond, The BugLady

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

Bug o’the Week – Stag Beetle Lucanus placidus

Greetings, BugFans,

The BugLady now lives on the edge of a sand dune, with some pine and spruce around the edges, and she’s looking forward to meeting her new six and eight-legged neighbors.  This stag beetle is the first species to step up (thanks, BugFan Becca, for the fancy footwork).

We have seen stag beetles (family Lucanidae) in these pages before, in the form of the Antelope beetle (http://uwm.edu/field-station/where-the-lizard-and-the-antelope-beetles-play/).  There are maybe 1050 species worldwide, with about 30 of those residing in North America and five in Wisconsin.  As a family, they’re among our most impressive beetles https://www.sciencenews.org/blog/wild-things/rhinoceros-beetles-horn-shape-reflects-fighting-style. Those mandibles/pinchers (“pinching bug” is a common name – watch out for the business end of these beetles) endear them to the scientific community; the variability in size and shape of the mandibles has fueled a century-and-a-half of discussions about exactly how a species is defined.  Within a species, scientists rank males with larger and fancier mandibles as male majors/high males and those with lesser mandibles as male minors/low males (body shaming in beetles?? Seriously??).

They are also, of course, prized by collectors, and there are any number of websites that sell them, dead or alive.

Stag beetles are associated with woodlands (though the star of today’s show likes sandy areas).  Eggs are laid in crevices in old stumps/trees or among their roots (though the star of today’s show may oviposit in sod), and the larvae may spend a few years feeding on decaying wood inside old tree trunks (though the larval star of today’s show may feed on the roots of shrubs).  The adults are variously reported to eat honeydew, tree sap, bark, or vegetation.  Adults tend to be nocturnal and to come to lights at night.

Lucanus placidus (it used to be listed in the genus Pseudolucanus), doesn’t have a common name, but its species name means “smooth” or “pleasing,” so let’s call it the Pleasing stag beetle.  Here’s another North American member of the same genus, a beetle whose range is just south of Wisconsin https://bugguide.net/node/view/1392398/bgimage.

Pleasing stag beetles can grow as long as an inch-and-a-half.  They are often dark, but they also come in a rusty color https://bugguide.net/node/view/635763/bgimage, and they have an amber-colored patch at the base of the front legs.  The surface of the elytra (the stiff, modified first pair of wings that covers the flying wings) is described as “shagreen,” which means that it has a roughish or granular texture, like shark skin.  They are chunkier than most other stag beetles and their mandibles are relatively short.

Like other Lucanids, they are sexually dimorphic – males are bigger than females, a reversal of the usual insect practice.  The female’s mandibles are smaller than the male’s, with a single tooth at the inner tip, and the male’s are larger and toothier.  The size of the mandibles and the number of teeth they bear differs among males of the same species, and a single individual may not even have symmetrical mandibles.

She has fancier front legs (tibia), though, with four long combs.  Those strong, front legs are used to dig tunnels six to eight inches deep, in which the adults escape the heat of the day.  After they were captured outside her back stoop, the BugLady refrigerated these beetles overnight (to slow them down a bit for their pictures), and when she photographed them where they had been found the night before, she found a beetle-sized hole right there!

Females, attract their suitors by releasing pheromones/perfumes into the air, sometimes with dramatic effects, and males use their mandibles to do battle for the favors of the females. Some observers have reported remarkable assemblages of these normally secretive beetles. For a great story by someone who was, suddenly, beetle-rich, read http://labs.russell.wisc.edu/insectlab/2016/06/23/buckets-of-beetles/.  The experts advise us that it’s not necessary to get out the pesticide – Pleasant stag beetles have a short shelf life and will be gone in a week or two.

Not a lot is known about Pleasant stag beetle biology, and their larvae are very difficult to distinguish from those of their close relatives.  Eggs may be deposited in sod, and the larvae migrate from there to find their preferred food source.  They feed about a foot below the surface of the soil and pupate in the ground, and when they become adults, they wait below the surface until dark to emerge.

Kate Redmond, The BugLady

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

Bug of the Week – River Damsels revisited

Howdy, BugFans,

The BugLady is still on hiatus but plans to get back in the saddle soon.  She spent a magic day at the river recently, where the bushes were sparkling with Ebony Jewelwings.  This is a slightly modified version of an episode from 2011 – some new words, all new pictures.

The stars of today’s show are two, big (close to 2”), beautiful, unmistakable members of the Broad-winged damselfly family Calopterygidae.  Once again, the BugLady would like to recommend Damselflies of the North Woods by Bob DuBois (watch for the 2nd edition, coming soon, if the creek don’t rise), Dragonflies and Damselflies of the East, by Dennis Paulson, the Beginner’s Guide to Dragonflies, by Nikula, Sones, Stokes and Stokes, and the on-line Wisconsin Odonata Survey (http://wiatri.net/inventory/odonata/).  There are eight species of Broad-winged damselflies in the US, and the Odonata Survey site lists four of those for Wisconsin – River and Ebony Jewelwings, and American and Smoky Rubyspots (but the Smoky Rubyspot has been recorded from only two counties in the extreme southern part of the state).

Broad-winged damselflies get their name from the base of their wings, which taper gradually instead of looking “stalked,” as in other damselflies.  When they sit, they hold their wings together vertically over the top of their abdomen.  They come in metallic colors, with the male showier than the female (the female is no slouch, though).

Like dragonflies and other damselflies, Rubyspots and Jewelwings are tied to the water – in this case, running water.  Other Odonates may hunt far from streams and ponds, but the Broad-winged damselflies tend to be homebodies.  They are perchers – sitting on plants or rocks and sallying forth to hunt or to defend their territories.  Rubyspots seldom gain more than a foot or two in altitude, but the BugLady has seen jewelwings seven or eight feet off the ground.  Like all Odonates, they are carnivores, both as naiads in their aquatic nurseries and as airborne adults, eating whatever small, soft-bodied invertebrates they can catch.  They are eaten by a host of bugs, bats and birds, as well as by some fish, frogs and turtles.

Ebony Jewelwings and American Rubyspots lay their eggs in the stems of submerged plants or in decaying wood in waters with a moderate current. The books say that the males guard their ladies during egg-laying but are not in contact with them (but keep reading).  Their naiads, which are well camouflaged and not agile, move little and are found on vegetation under water.  Broad-winged damselflies overwinter as naiads, and full grown naiads are about an inch long by the time they are ready to emerge as adults the next summer.

EBONY JEWELWINGS (Calopteryx maculata) (“beautiful wing with a spot”) prefer streams in woods east of the Rockies, and they are said to be the most common damselfly in North America (they certainly are among the most striking).  Their main flight season is in June and July but a few hang around into September.  Several sources testified about their approachability and the BugLady laughed a lot – they can be pretty jumpy.  The flight of Ebony Jewelwings is often described as “butterfly-like,” and they remain on the wing until late in the afternoon.

Male Ebony Jewelwings (a.k.a. Black-winged damselflies) have a stunning Kelly-green, metallic head, thorax and abdomen (unless you see them from a certain angle, and then they are a shiny royal blue), spectacular coloration that effectively camouflages them in the sun-dappled wetland edges that they inhabit. The females’ greens and blacks are more muted and they have a white dot at the tip of each wing.

Donald Stokes, in his wonderful Observing Insect Lives, reports that males are territorial.  When an Ebony Jewelwing spots an intruding male, he will attempt to chase it away.  The two males bounce off each other until one wears out and gives up (males are territorial around patches of floating aquatic vegetation, and patches of the river may sparkle with them).  Plan B involves a behavior called “wing-spreading,” in which he psyches out his rivals by spreading his wings and raising his abdomen (raising the abdomen displays a bright, white spot under its tip which the BugLady has never seen).  An approaching female rates a “cross-display,” in which the abdomen is raised, the hind wings spread, and the front wings folded.

According to Stokes, if a female is unimpressed, he flies around in front of her, faces her, and performs the irresistible “rapid-wing-flutter.”  Both males and females have commitment issues.  DuBois rates her as “blatantly promiscuous,” mating with four or five different males a day for two weeks or so and depositing nearly 2000 eggs!  Stokes says that while the male is guarding her egg-laying efforts, he is making cross-displays to nearby females (though he won’t pursue them until she is finished and out of sight).

The AMERICAN RUBYSPOT (Hetaerina americana) likes larger streams and rivers; its range includes all of the lower 48 states (it’s uncommon in the Pacific Northwest) plus the eastern half of Canada around the east edge of Hudson Bay.  The American Rubyspot is a summer damselfly that notably likes a crowd (one observer caught 75 in a single net), and it has been observed feeding in groups (swarm-feeding) on clouds of emerging mayflies.  The reason for its name is obvious if you see a male in bright sunlight, but in shade their posture is characteristically “hunched over,” and they are not as conspicuous.  The BugLady often sees them as red dots on rocks or on floating plants in the river.  The proximal third of the male’s wing is ruby/blood red (according to Paulson, the spot starts small and grows in size for about two weeks).  The (more variable) female’s wing often has a red wash at the base, and its overall color is often amber.

Males defend territories that change daily, chasing rival males in ever-widening circles until one poops out and flies off and the other claims/reclaims the spot.  Females are also somewhat territorial, but neither gender has display behaviors like the Ebony Jewelwing.  Receptive females fly into a territory, hover, and are grabbed/clasped by the male.  As they fly in tandem to a perch to exchange bodily fluids, rival males may charge them and separate them. Duke University professor Clifford Johnson described how, still clasped, they may land on a floating mat of vegetation.  The male walks backwards toward the water with the female backing up behind him until the female is fully submerged (several sources noted that she is partly to completely submerged while laying eggs, but she will enter the deep end on her own, too).  She may stay under water briefly or for almost an hour (in fact, though other researchers have seen them, Johnson said he never saw a female re-emerge and wondered where/if they did).  The male guards her from all comers – con-specific or not.

Ironically, those crimson wing spots that make us gasp render males potentially more visible to predators as they cruise low over the river’s surface.  And, it turns out, they are also a “hunting handicap” that make males more visible to their own flying prey.  In one study, males (and females with red spots painted onto their wings) gained weight more slowly than the better-camouflaged “natural” females.  The things we do for love.

Find a river and enjoy the show.

Kate Redmond, The BugLady

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

Become a Member

Take advantage of all the benefits of a Riveredge membership year round!

Learn More