Bug o’the Week – And Now for Something a Little Different XV – Royal Catchfly

Bug o’the Week
by Kate Redmond

Bug o’the Week And Now for Something a Little Different XV Royal Catchfly

Greetings, BugFans,

The BugLady had a long overdue “Oh Duh!!!”moment recently when BugFan Freda asked her if she realized why Royal Catchfly flowers were named Catchfly. Nope – hadn’t thought about it (insufficient scholarship).

Freda had just discovered, to her horror, that she might be aiding and abetting pollinator murder. Did the BugLady know that the Royal Catchfly was, in fact, a pollinator deathtrap? She had planted a small patch of native wildflowers in order to attract pollinators, and while she was admiring the Catchfly’s beautiful red flowers, she noticed a dead bumblebee. She took a closer look and saw a dead honeybee, one very much alive honeybee that was completely stuck and was trying to pull free from the sticky plant, and a small leafcutter bee that was in the same predicament (and when she gently pried a bee out of the glue, it remained so sticky that it couldn’t fly). There were at least two dead, and two dying bees in her pollinator patch.

Thanks, Freda, for the question (and for most of the pictures).

First off, what’s a Royal Catchfly?  It’s a brilliantly red, native wildflower in the Pink/Carnation family Caryophyllaceae and in the large genus Silene.  Silene is a complicated genus, and various aspects including its genetics, speciation, and the complicated reproductive strategies of some species have been studied for a long time.  Varieties of Silene are planted in perennial gardens and sold by florists, and some, like the non-native Bladder campion (Silene vulgaris) are eaten https://www.minnesotawildflowers.info/flower/bladder-campion.   

Royal catchfly is historically a plant of prairies, savannahs, woodland openings, roadside edges, and railroad rights-of-way, and today it’s considered widespread, but patchily distributed.  Over much of its range, which lies from Kansas and Oklahoma to Ohio, down to northern Florida, it’s considered to be Rare, Endangered or Threatened, and it’s been extirpated (driven locally extinct) from a few states due to habitat loss, invasive plant thuggery, shade, lack of fires, and humans with shovels.

Royal catchfly (Silene regia), and a number of other Silene species, are called “catchfly” because they catch flies.  They are adorned with sticky, gluey hairs (glandular trichomes) on the calyx (the green “vase” that’s formed by the sepals at the base of the flower) and on the upper stems.  The calyxes of older flowers that have shed their petals are a bit tacky, but not actively gluey like the younger flowers, and the leaves are fuzzy but not sticky.    

The sticky hairs (and some stiff, downward-pointing hairs toward the bottom of the plant) are very effective in stopping insects that might try to climb up the stem toward the flower (though one author had seen some aphids and their guardian ants navigating the stems).  They’re equally effective in deterring “nectar robbers” – insects like bumble bees whose tongues aren’t long enough to reach the nectar prize from the top of the flower, so they chew their way through the calyx from the side, sip the nectar, and don’t do any pollinating at all.  One author says that the plant is “selecting for” airborne pollinators,” the chief of which is the Ruby-throated hummingbird, though moths with long proboscises that hover in front of the tubular flower could get away with it, as can swallowtail butterflies.  Insects can’t see the color red (hummingbirds can), and apparently, although many insects can see ultra-violet light, a UV image of Royal catchfly doesn’t reveal any insect “come hither” signals.   

What happens after the bugs get caught? 

The logical leap is that having gone through the effort of catching them (producing the hairs requires an energy investment from the plant, after all) the catchfly uses them.  Some sources speculated that this kind of insect entrapment might be a step toward an eventual life of carnivory and wondered if the catchfly had any way to absorb the nutrients in its victims, like a sundew does.  In his Master’s Thesis in 2017, Garrett John Dienno held up two yardsticks to measure the Royal catchfly’s possible carnivory: “1) whether S. regia actively attracts, captures, and retains prey, and/or secretes digestive enzymes to facilitate nutrient absorption; and (2) whether it absorbs and translocates the resultant nutrients.”  Spoiler alert – No and No.  There is no insect-attracting nectar and no UV signal, and the glandular hairs do not secrete any digestive enzymes.  He concluded that “Instead, we propose the glandular trichomes on the S. regia calyx provide a passive defensive benefit to the flowers and seeds by protecting the very structures that are supporting their development.” 

The published word on the catchflies is a bit murky, though, and there’s some just plain bad information out there.  One otherwise respectable plant nursery noted that Royal catchfly comes from a carnivorous family (possibly the same nursery that once claimed that Cup Plant (https://www.illinoiswildflowers.info/prairie/plantx/cupplantx.htm) digests the insects that drown in the water pools formed by their perfoliate leaves).  The Pink family Caryophyllaceae is not known for carnivory, but the Order it’s in, Caryophyllales (a much bigger umbrella) does include some families with carnivorous plants (it also contains cacti and beets).  What a difference a few letters make!

A number of nursery catalogs and other publications state that because having small, rotting insects stuck to their stems would be unhealthy for Royal Catchflies, the plants get rid of the bodies by secreting enzymes that break them down before they “get putrid.”  Self-preservation rather than nutrition.  Way back in 1876, a Professor W. J. Beal wrote about a related plant that “We need not necessarily suppose that they are digested because they are captured by sticky plants.”  

A gardening site’s description of the related and equally sticky Night-flowering catchfly, which is pollinated by moths, said that “When the moth touches the plant it finds that it cannot get away easily and so is more likely to get covered in pollen, or release any pollen it is already carrying, as it tries to break free. This it will do, because the plant is not insectivorous and is only interested in temporary prisoners rather than permanent ones.”  So, happily, the plant’s intent is not to harm it.  

One nursery suggested that the stuck bugs might provide a feast for insectivorous birds.  The BugLady can picture the hummingbirds that come for nectar noticing the stuck insects and picking them off the plant (small insects are a regular part of their diets) but she can’t picture sparrows or chickadees doing that.  It’s possible that long-legged insects like wasps and yellowjackets, which forage for protein for their larvae, might check the catchfly’s offerings.

The British are not immune to this silliness.  Back in 2009, Scientists from the Royal Botanic Gardens, Kew and the Natural History Museum concluded that petunias, potatoes, and several other common plants were meat eaters – or at least on the way to being meat-eaters.  Why?  Because they have sticky hairs that trap bugs.  After making a big splash on both sides of the Pond, they walked it back a bit.  “However, some of the commonly accepted carnivores [like petunias] have not been demonstrated to have the ability to digest the insects they trap or to absorb the breakdown products.” 

They went on to say “Professor Mark Chase, Keeper of the Jodrell Laboratory at the Royal Botanic Gardens, Kew says, ‘…. many commonly grown plants may turn out to be cryptic carnivores, at least by absorbing through their roots the breakdown products of the animals that they ensnare. We may be surrounded by many more murderous plants than we think.’”  Nice save?

There’s a reason why scientists submit papers for peer review.

(The BugLady is reminded of Nathaniel Hawthorne’s short story “Rappaccini’s Daughter.”)

Kate Redmond, The BugLady

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

Bug o’the Week – Midsummer Memories by Kate Redmond

Bug o’the Week
by Kate Redmond

Bug o’the Week Midsummer Memories

Howdy, BugFans,

Last year the BugLady had so many midsummer stories to tell that she wrote one episode about dragonflies, and a second about “other” (because as seasoned BugFans know (well) her camera gravitates to dragons and damsels).  She’s got a heap of pictures to share again this year, but she’ll mix and match the groups in a two-part summer feature.

ROSE CHAFER BEETLE – The BugLady saw a single Rose Chafer last year and wrote about it https://uwm.edu/field-station/rose-chafer-beetle/.  This year, she found bunches of them – orgies of them (she’s not sure what the collective noun for Rose Chafers is, but she’s pretty sure it’s “orgy”).  And she was enthralled by the leggy designs they made on the undersides of milkweed leaves.  

COPPER BUTTERFLY – A highlight of the BugLady’s recent explorations of Kohler-Andrae State Park was finding two species of Copper butterflies – American Copper and Bronze Copper (she rarely finds Coppers).  The Coppers are in the Gossamer-wing butterfly family Lycaenidae, along with the Harvesters, Hairstreaks, Elfins, and Blues.  Their caterpillars feed on plants in the rose and buckwheat families (dock, sorrel, and knotweed).

VIOLET/VARIABLE DANCER – The BugLady was talking to a friend recently about the colors that dragonflies and damselflies come in.  Black, black and yellow, green, blue – even red.  But purple?

FLY ON PITCHER PLANT – This is just the way it’s supposed to work.  Insects with a “sweet tooth” get lured to the lip of the pitcher plant and partake of the (slightly narcotic) nectar there.  Judgment impaired, they mosey around a little, maybe venturing onto the zone of down-pointing teeth below the lip, and then onto the slick, waxy zone below that.  It’s all downhill from there.

GOLDENROD CRAB SPIDER on yarrow (not all Goldenrod crab spiders have red racing stripes).  Incoming insects have trouble seeing her, too.  Out of all the species of crab spiders in the world (about 3,000), only a very few have the ability to change colors, and that ability is limited to the female of the species.  Her color palette includes white, yellow, and pale green.  She sees the background color with her eyes, and because a wardrobe change takes her between three days and three weeks she tends to stay on her chosen flower.  Her base color is white, and switching involves either creating yellow pigment or reabsorbing and then sequestering or excreting it.  

Why?  Good question.  Scientists have tested spiders on matching and non-matching flowers (which they often sit on), and they saw no boost in hunting success when the spiders matched their background (she likes prey that’s bigger than she is, like bumblebees, because she has eggs to make.  She loses weight on a diet of small flies).  When spiders themselves are the prey, they are not picked off more often on non-matching flowers.  Maybe the color change gives her some sort of advantage when she forms her egg case, or maybe it’s a vestigial solution to a long-ago problem.

ORANGE-LEGGED DRONE FLY – This Syrphid/Flower/Hover fly is so serious about its bumble bee disguise that it makes a loud buzz when it’s flying

SEDGE SPRITE TUSSLE – the BugLady was in a bog not long ago when she saw two damselflies tussling on some leaves.  At first, she thought there was some predation going on, but that didn’t make sense because they were both Sedge Sprites.  He had grabbed her and was wrestling with her, and she was having none of it.  He suddenly flipped her around and clasped the back of her head with the tip of his abdomen (SOP for mating dragonflies and damselflies).  Rather than reaching forward and taking his sperm packet, she ultimately gave a couple of good shakes and dislodged him.  One small drama.

PHANTOM CRANE FLY – Flies come in all sizes and shapes, but this magical creature in white spats is the BugLady’s favorite.  It lives in dappled, brushy wetland edges where it flickers through the vegetation like a tiny wraith.

FORKTAIL AND POWDERED DANCER – Eastern Forktails are voracious hunters that go after other damselflies, even those close to their size.  The mature female forktail (in blue) found a teneral (young) Powdered Dancer (in tan) that was probably not a strong flyer yet.

Go outside – look at bugs,

Kate Redmond, The BugLady

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

Bug o’the Week – the Missouri Bee-killer Robber Fly

Bug o’the Week

the Missouri Bee-killer Robber Fly

Howdy, BugFans,

Robber flies are a very cool bunch of flies that we have visited a number of times in the past.  To appreciate the array of sizes and shapes and colors of Wisconsin robber flies from the tiny “Gnat ogres” https://bugguide.net/node/view/2036908/bgimage, to the bumble bee mimicking Laphria https://bugguide.net/node/view/612780, to the Giant robber flies in the subfamily Asilinae (like today’s star) https://bugguide.net/node/view/1424049/bgimage, visit the robber fly corner of the wisconsinbutterflies.org website https://wisconsinbutterflies.org/robberfly.

Besides being awesome-looking, these “bearded” flies (sometimes called Assassin flies) are predators, and they are not shrinking violets.  In the Field Guide to the Insects of North America, Eric Eaton says that “Robber flies (family Asilidae) are to other insects what falcons are to other birds.”  In an article published in the Bulletin of the Brooklyn Entomological Society in 1949, S. W. Bromley tells us that “Linneaus … gave this group of flies the name Asilus (the ancient name for flies which tormented cattle) in the belief that they were molesters of stock and cattle, a habit in which no robber fly today is known to indulge.”

Robber flies’ modus operandi is to spot an insect from their perch, grab it (and they will go after insects larger than they are), inject it with saliva to both kill it and soften its insides, and then perch and ingest the liquid through a tube called the hypopharynx.  They eat lots of insects that are agricultural pests, but they haven’t been formally deployed as biological controls because they are equally likely to eat honey bees and Monarch butterflies.  

There are about 1000 species of robber fly in North America, and the Missouri bee-killer (Proctacanthus milbertii), akaMilbert’s Proctacanthus, is one of 17 members of its genus north of Mexico.  Bromley notes that “In Southern Alabama, Col. S. F. Blanton stated that it has received the common name of ‘Boo-hoo fly.’”   

The spectacular Missouri bee-killer is found from sea to sea, and north and south of our borders in sort of a checkerboard pattern https://bugguide.net/node/view/46891/data (the range maps in bugguide.net come with a disclaimer that says, “The information below is based on images submitted and identified by contributors. Range and date information may be incomplete, overinclusive, or just plain wrong.”).  According to Bromley, “Milbertii has for its habitat fields and pastures where the soil contains a considerable admixture of sand.”  It’s often found around goldenrod, and it’s pretty well camouflaged when it sits on the ground surrounded by dry goldenrod leaves.  The Missouri bee-killer is a late-season robber fly, and it’s one of the species that the BugLady found in the dunes at Kohler-Andrae State Park. 

There’s some variation in color – the beard is creamy white, but some individuals aren’t as maroon than the one the BugLady found https://bugguide.net/node/view/230984/bgimage.  They are active and noisy fliers, and they like to rest on open ground. 

Males are territorial and will chase rival males.  Robber fly courtship is a no-frills affair – he approaches her much like he approaches prey.  After mating (https://bugguide.net/node/view/977130/bgimage), she works her abdomen barely into the soil or sand https://bugguide.net/node/view/1168742/bgimage and lays her eggs.  She visits flowers before ovipositing because for best results, she must take in both protein and sugar before she oviposits.  The larvae live in the soil and prey on invertebrates they find there, and they may also nibble on decaying plant material.  In some robber fly species, the larva lives in the soil for up to three years before it pupates.  

In a 1975 article in The Great Lakes Entomologist, Norman T. Baker and Roland L. Fischer wrote that “P. milbertii exhibits a very interesting defensive reaction when attacked by another fly. The attacked fly nearly always spreads its legs and wings outward and upward and curves the abdomen upward. Generally the fly turns to face the attacker and then tilts backward allowing it to better fend for itself. Usually the wings are buzzed in short bursts.”

Although some closely-related robber flies do concentrate more on them, Missouri bee-killers are generalists whose diet doesn’t include many honey bees (only 4%, according to one study).  Grasshoppers https://bugguide.net/node/view/144982/bgimage and moths https://bugguide.net/node/view/990141/bgimage make up about three-quarters of their food, and they also prey on butterflies, beetles, bugs, bees (including bumble bees https://bugguide.net/node/view/141843/bgimage), and flies, and they’re not above a little cannibalism.  In a study area in the Nebraska sandhills, researchers counted 437 Missouri bee-killers per hectare (one hectare is a little less than 2.5 acres) and 64,000 grasshoppers from 23 species per hectare.  The flies devoured one to two grasshoppers per day, each, consuming an average of nearly 2% of the population of adult grasshoppers daily. 

They fly fast, pick their prey out of the air, and land to feed.  They wrap all six legs around it and administer a killing jab behind the prey’s head, often lying on their side until the prey is dead https://bugguide.net/node/view/144985/bgimage.  They pierce their prey often as they feed in order to reach all its nooks and crannies, manipulating it with their forelegs.  If you must handle a robber fly, handle it with care, because the larger species can jab painfully. 

Baker and Fischer’s documentation of the daily routine of Missouri bee-killers included observations of its sleep habits.  They wrote “These flies are quite active as long as the proper habitat is hot and sunny. When dusk approached, and the sun no longer shone on the habitat of P. milbertii, the flies cease all activity. Attempts to discover where they spent the night were nearly futile until it was discovered that the flies were resting in or under dead leaves beneath nearby trees or bushes. When the sun set the flies “entered a stupor” and became very inactive. If disturbed they would buzz their wings for a second or two and then again become inactive. Perhaps the buzzing will frighten a possible predator. The positions these flies may assume are often ridiculous. They appear to be dead. In one instance a male was discovered “standing on his head” and supported only by his front legs. Hull (1962) has also observed this behavior and interpreted it as ‘death feigning.’”  Here’s an early morning shot https://bugguide.net/node/view/835010/bgimage

Go outside – look for bugs – it’s not too late!

Kate Redmond, The BugLady

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

Bug o’the Week – Early Summer Scenes

Bug o’the Week

Early Summer Scenes

Howdy, BugFans,

Well, the sun has solsticed, and it’s all downhill from here.  Our pre-Christian, Germanic ancestors, who were more intimately attuned to the rhythms of the sun, correctly celebrated the winter solstice, aka Yule (which may have come from the Norse word houl, which referred to the sun as the wheel that changed the seasons).  They recognized that the winter solstice marked a turning point that would lead to longer, warmer days.

In the BugLady’s neck of the woods, the insect world is dominated these days by mining, sweat, and bumble bees and by lots of flies, including a big hatch of mosquitoes that timed their appearance to coincide with the Riveredge Butterfly and Dragonfly count (causing the BugLady to move along the trail rather smartly).  Here’s what she’s been seeing in the run-up to summer.

STILT BUG ON FERN: This started out as a fern fiddlehead picture – the BugLady did not see the stilt bug when she took the picture, it was one of those happy surprises that photographers get when they put an image up on the monitor.  Most stilt bugs/thread bugs are plant-eaters that supplement their diet of plant juices with the odd, small invertebrate.  Some are more “meat-oriented,” and one species is used to control Tobacco hornworms.

CRAB SPIDER: A friend of the BugLady’s recently asked where all of the beautiful, plump crab spiders are.  They’re here, but they have some growing to do.

KATYDID NYMPH: And another friend, from Southern climes, asked if the BugLady was seeing katydids yet.  Same answer.

TIGER BEETLE: The BugLady loves seeing the flashy, green Six-spotted tiger beetles.  Usually they perch on a bare path, wait until you get too close, fly ahead of you about a foot above the ground, land, and repeat the process when you get too close again.  Until this year, the BugLady had never seen one off the ground, but she’s photographed three in the past month.  Get to know Wisconsin’s tiger beetles at https://wisconsinbutterflies.org/tigerbeetle.

MILLIPEDE ON RUST: Millipedes are decomposers/detritivores, feeding on dung, plant juices, and pieces of dead plant materials like decaying leaves, breaking them down for organisms even smaller than they are.  Some like fungi. 

If you’ve seen the invasive shrubs Glossy and Common buckthorn, you’ve probably seen stems and petioles with a bright orange blob on it.  The blob is a rust – a fungus – called Crown rust (Puccinia coronata).  Buckthorn is one of its hosts, and the alternate hosts are a variety of grasses, including agricultural crops like oats and rye.  If you see grass leaves with thin orange streaks on them, you’re probably seeing a variety of crown rust.  Crown rust has a complicated life cycle (http://www.minnesotaseasons.com/Fungi/Crown_Rust.html ), but the bottom line here is that the rust on buckthorn releases its spores in a soupy, sweet liquid that attracts insects, and the insects carry the spores to rust patches on other buckthorns and fertilize them.  The rust probably doesn’t get much bang for its buck when its spores are eaten by a short-legged pedestrian like a millipede.

BALTIMORE CHECKERSPOT CATERPILLER: The astonishing Baltimore Checkerspot https://bugguide.net/node/view/1771510/bgimage and https://bugguide.net/node/view/1636206/bgimage, and its caterpillar, is one of the BugLady’s favorites.  This caterpillar hatched last summer and munched on its host plant (historically white turtlehead, but in the past 50 years, they’ve adopted Lance-leaved/English plantain, and those are the only two plants a female will oviposit on).  It overwintered as a caterpillar, woke up hungry this spring, and looked around, – no turtlehead in sight yet – so it’s been eating a variety of plants, especially white ash.  Both turtlehead and plantain leaves contain poisonous glycosides (turtlehead has more), allowing the caterpillar and butterfly to get away with their gaudy colors.  And remember – the butterfly (and the oriole) get their names not because they were discovered in that city, but because 17th century English nobleman Lord Baltimore, a familiar figure to the colonists, dressed his servants in orange and black livery. Get to know Wisconsin’s butterflies at https://wisconsinbutterflies.org/butterfly.

MONARCHS: Most of the Monarchs that return to Wisconsin are probably Gen 2 – the second generation north of their wintering ground in Mexico.  There ensues two short-lived generations – Gen 3 and 4 – whose only job is to increase the population, and these two clearly got the memo.  Gen 5, produced in August, is the generation that is signaled by both waning day length and the lowering angle of the sun to migrate instead of reproducing (though there always seem to be a few that didn’t get that memo). 

BEE ON LEATHERWOOD: At a quick glance, you might think that this is a bumble bee, but bumble bees have hairy butts.  The BugLady thought this was a carpenter bee (which have shiny butts), but now she thinks it’s one of the larger mining bees in the genus Andrena.  Leatherwood is a spring-blooming shrub in woodlands – those fuzzy bud scales protect the bud from chilly spring nights.  It gets its name from the fact that its branches can’t be torn off the shrub, and from its strong bark fibers, which were woven into baskets, bowstrings, ropes, and the cords that lashed together canoe frames.  Settlers used its branches when they took their children to the woodshed.  All human use of it is problematic, because its caustic bark raises some serious blisters.

ROBBER FLY: Another bumble bee look-alike.  Bumble bees eat nectar and collect pollen to feed their larvae; robber flies are carnivores.  Laphria thoracia (no common name) can be found on woodland edges from the Mason-Dixon Line north into the Maritime Provinces and west through the Western Great Lakes.  Adult Laphria thoracia eat bees and adult beetles (this one has a clover weevil, but the BugLady recently photographed one with an assassin bug), and their larvae feed on beetle larvae in decaying wood.  Get to know Wisconsin’s robber flies at https://wisconsinbutterflies.org/robberfly  

GOLD-BACKED SNIPE FLY: June is the only month to enjoy these dramatically-colored flies that perch low in the vegetation in moist areas. 

SWAMP MILKWEED BEETLE: The BugLady loves finding these “ladybugs-on-steroids.”  They’re often tucked down into the axils of the milkweed leaves, and when they see company coming, they either duck down deeper into the crevice or they default to the typical escape behavior of an alarmed leaf beetle – they tuck in their legs and fall off the plant.  Their bright (aposematic/warning) colors tell potential predators that they are toxic, due to the milkweed sap they ingest, but damsel bugs, stink bugs, and flower/hover/syrphid fly larvae prey on them nonetheless.  For the full (and fascinating) Swamp milkweed leaf beetle story, see https://uwm.edu/field-station/swamp-milkweed-leaf-beetle/.  

ICHNEUMON WASP: Every year, large and colorful Therion (probably) Ichneumon wasps drift through the vegetation in perpetual motion, legs dangling, taunting the BugLady https://bugguide.net/node/view/739675/bgimage.  They often occur in wetlands, and the BugLady swats mosquitoes and deer flies as she waits for them to show their faces.  Which this one did.

Experienced BugFans are saying, “But, but, but – where are the dragonflies?”  Tune in next week.

Go outside – look for bugs.

Kate Redmond, The BugLady

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

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