Tag: summer

Bug o’the Week – Bugs at the End of Summer

Bug o’the Week

Bugs at the End of Summer

Howdy, BugFans,

The general rule of thumb is that if you want to find insects, look at flowers.  Even though summer is fading, there are still flowers in bloom.  Some Liatris/blazing stars linger, along with brown-eyed Susan, wild sunflowers, asters and goldenrod (more than a century ago, Asa Gray said that the 12 pages about goldenrods in his Manual of the Botany of the Northern United States, from New England to Wisconsin and South to Ohio and Pennsylvania Inclusive (aka Gray’s Manual) were the most uninteresting in the Manual).  Late summer and early fall are dominated by flies, bees and wasps, and by grasshoppers, katydids, and crickets.

Most adult insects die by the first frosts, leaving behind the next generation in the form of eggs or pupae (occasionally as nymphs or larvae), so the clock is starting to tick pretty loudly.  As BugFan Mary stated dispassionately many years ago, they’re dead and they don’t know it yet.  Meanwhile, their activities are centered on eating and on producing the next generation.

AMBUSH BUG (pictured above) – One of the BugLady’s favorite insects is the ambush bug (she’s always had a soft spot in her heart for predators).  Ambush bugs tuck themselves down into the middle of a flower and wait for pollinators.  They grasp their prey with their strong front legs, inject a meat tenderizer, and slurp out the softened innards.  They’re paired up these days (the BugLady has a picture of a stack of three), and she has several pictures where the female is multitasking – eating an insect while mating.

BUMBLE BEE – A bumble bee forages for nectar and pollen for the brood well into September, but the brood will not survive the winter.  Only the newly-fertilized queens will see the spring and establish a new colony.  Moral of the story – plant Liatris/Blazing star.

PUNCTURED TIGER BEETLES (aka Sidewalk or Backroad Tiger Beetles) are named for the rows of pits on their very-slightly-iridescent elytra (hard wing coverings).  They’re common across the continent in dry, sandy, bare spots, and as one of their names suggests, they’re sometimes seen on sidewalks.  Like their (much) larger namesakes, Tiger beetles chase their prey https://bugguide.net/node/view/1106590/bgimage.  For more info http://www.naturenorth.com/Tiger%20Beetle/The%20Tiger%20Beetles%20of%20Manitoba.pdf.  

Some Punctured tiger beetles are “plain” https://bugguide.net/node/view/1343674/bgimage, and some are “fancy” https://bugguide.net/node/view/223895, and some are green https://bugguide.net/node/view/2025474/bgimage.  

FAMILIAR BLUETS signal the end of the damselfly season.  Big, robust, and startlingly-blue, they’re one of the BugLady’s favorite bluets.  

EASTERN COMMA – There are two generations/broods/”flights” of Commas (and Question Marks – the “anglewings”) each year.  The second generation overwinters as adults, tucked up into a sheltered spot (a hibernaculum).  They sometimes emerge during a January thaw, but they quickly resume their winter’s sleep.  They fly briefly in spring – one of our early butterflies – and produce the summer brood.

FALL FIELD CRICKET – Poking her ovipositor into the soil and planting the next generation.  Her eggs will hatch in spring, and her omnivorous offspring will eat leaves, fruits, grain, and other invertebrates. 

The BugLady loves their simple songs http://songsofinsects.com/crickets/spring-and-fall-field-crickets and is happy when a cricket finds its way indoors in fall.  Males form a resonating chamber by setting their wings at a certain angle; then they rub their wings together to produce sound (one wing has a scraper edge and the other has teeth).  There are mathematical formulae for calculating the ambient air temperature based on cricket chirps that give you the temperature in the microclimate on the ground where the cricket is chirping (add the number of chirps by a single field cricket in 15 seconds to 40). 

CANADA DARNER – Common Green Darners are robust dragonflies that fill the late summer skies with dramatic feeding and migratory swarms.  There are other darners, though, primarily the non-migratory mosaic darners (like the Canada, Green-striped, Lance-tipped, and Shadow Darners) whose abdomens have blue and black, “tile-like” patterns.  Identify them by the shape of the colored stripe on the thorax and by the shape of the male’s claspers (lest you think it’s too easy, females come in a number of color morphs – this is a green-form female Canada Darner).  

MONARCH BUTTERFLIES were alarmingly scarce this summer – the short-lived Gen 3 and Gen 4, whose job it is to build the population in the run-up up to the migratory Gen 5, simply weren’t there.  But, on one of the BugLady’s recent stints on the hawk tower, she saw 289 Monarchs heading south during a six-hour watch.  Moral – Plant goldenrod (and native milkweeds).

GOLDENROD CRAB SPIDER – Like ambush bugs, crab spiders live on a diet of pollinators.  They don’t build trap nets and wait for their prey to come to them, they pursue it.  Sometimes they lurk on the underside of the flower, but their camouflage makes hiding unnecessary.  This female looks like she’s sitting at the dinner table.

RED-LEGGED GRASSHOPPERS are very common in sunny grasslands at this time of year from coast to coast.  They eat lots of different kinds of plants (including some agricultural crops, which does not endear them to farmers), but they prefer plants in the Legume/pea family and the Composite/aster family.  As the air temperature increases – and when predators are around – they eat more carbs.  Grasshoppers are food for spiders, many birds, and other wildlife.  Moral of the story – plant wild sunflowers.

PAINTER LADY – You don’t get to be the most widespread butterfly in the world (found everywhere except Antarctica and South America) by being a picky eater.  It migrates north in spring – sometimes in large numbers and sometimes in small.

THIN-LEGGED WOLF SPIDER – This Thin-legged wolf spider formed an egg sac (with about 50 eggs inside), attached it to her spinnerets and is going about her business.  When the eggs hatch, her young will climb up on her abdomen and ride around piggyback for a few weeks before dismounting and going about their lives. 

Great black wasp
Great golden digger wasp

GREAT BLACK WASP and GREAT GOLDEN DIGGER WASP – Two impressive (1 ¼” long) wasps grace the flower tops at the end of summer.  Both are good pollinators, both are solitary species that eat pollen and nectar, and both dig tunnels and provision chambers with paralyzed insects for their eventual offspring.  Great Black Wasps https://uwm.edu/field-station/great-black-wasp/ select crickets and grasshoppers for their young’s’ pantry, and so do Great Golden digger wasps https://uwm.edu/field-station/great-golden-digger-wasp-family-sphecidae/.  Neither is aggressive.  

The moral of the story?  Plant lemon horsemint.

Kate Redmond, The BugLady

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

Bug o’the Week – Sanborn’s Beewolf

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Their common name, beewolf, describes what they do, and their genus name, Philanthus, from the Greek for “lover of flowers,” describes where they do it.  They’re also called digger wasps, bee-hunters, and bee-killer wasps.  There are about 140 species of beewolves spread across North America (32 species), Europe, and Northern Africa, and the European beewolf (Philanthus triangulum), a honeybee specialist, is probably the most famous/most studied. 

The natural history of Sanborn’s beewolf is, with a few tweaks, similar to that of many solitary wasps – the female digs a tunnel with separate chambers for each egg.  She stashes paralyzed prey in each, and when each cache meets with her approval, she lays an egg in it, seals the chamber, and closes the tunnel.  The eggs hatch; the larvae eat the still-living bees left by Mom (beewolf Moms leave another gift as well – more about that in a sec), and emerge the following spring.  Adults are nectar-feeders and are good pollinators. 

Let’s flesh that out a little for beewolves in general and Sanborn’s beewolf in particular.

Males emerge from the nest tunnels in late spring/early summer a few days before females.  They mark territories by depositing on twigs some pheromones made in their mandibular glands, and these pheromones both attract females and warn other males of the territorial boundaries.  Territories are about food and generally contain attractive nectar or honeydew sources.  After they mate, the female Sanborn’s beewolf digs a tunnel up to 10 inches long (she likes packed sand, which is probably why the BugLady found her in the dunes) and starts provisioning it.  Here’s a nice series showing her at work – https://bugguide.net/node/view/1084968/bgimage.  Males dig shallow burrows to spend the night in.

About Philanthus genus members, Heather Holm, in her massive and brilliantly-illustrated book Wasps, tells us that, “Many Philanthus females excavate accessory burrows near the real nest burrow entrance.  These burrows may play a role in distracting natural enemies such as bee flies (family Bombyliidae) or satellite flies (family Miltogramminae) because they remain open while the real nest burrow is closed when the female is away from the nest.”  The BugLady saw a number of bee flies along the trail that day – a future BOTW if she can only ID them.  

She visits a flower, and according to Holm, if she sees an appropriately-sized bee on it, she “hovers downwind to detect the prey’s scent for confirmation, then returns to the flower to capture and sting the prey.”  She apparently judges the readiness of each nest chamber by bulk – packing in larger numbers of small prey and smaller numbers of large prey, and Holm says that a female makes only one nest tunnel in her lifetime.    

Sanborn’s beewolves are larger than the average beewolf and so can pursue larger prey.  They are generalists – almost everything is fair game as long as they can subdue and carry it, and they don’t play favorites.  Menu items include more than 100 different species of bees and small wasps including honey bees, long-horned, mining, leafcutter, and sweat bees, and fellow crabonids.  Beewolves deliver venomous stings, aiming for the underside of their prey’s thorax, between the legs, and they grip their prey so that if it tries to sting back, it can only reach an armored section of beewolf.  

Beewolves spend a lot of down-time. The egg is laid near the top of the pile of paralyzed bees; the larva emerges from the egg by mid-summer and consumes the food cache, makes a cocoon, and goes into a prepupal stage within its cell.  It doesn’t pupate until the next spring/early summer shortly before it is scheduled to emerge for its short (a little more than a month) adult life. 

Now – the BugLady knows that you were told that there would be no microbiology…….

Beewolves have developed a very cool way to boost the fitness/survival/success of their offspring.  Along with fresh meat, the female beewolf leaves for her offspring what one source calls a bacterial birthday present.  Female beewolves cultivate in the base of their antennae a white paste that contains Streptomyces.  Streptomyces is a large genus of bacteria that’s used (by us) in the production of antibiotic, antifungal, anti-parasitic, and immunosuppressant drugs (think neomycin and streptomycin, among others).  The bacteria associated with beewolves has been named Candidatus Streptomyces philanthi’. 

What does she do with it?  She leaves some in each brood cell, and the larvae find it and incorporate it into their cocoons.  Brood chambers are warm and dark and moist – perfect petri dishes for a variety of soil microbes that might infect a larva or pupa.  Candidatus Streptomyces philanthi’.produces at least nine different antibiotics that protect against bacterial and fungal infections (researchers Seipke, Kaltenpoth and Hutchings call it a “multi-drug therapy”).  Scroll down to the great videohttps://medium.com/hhmi-science-media/life-cycle-of-philanthus-digger-wasps-the-beewolf-d8ae2d1135db.  After this phenomenon was discovered in beewolves, it was found in two species of mud dauber wasps – this may be a “tip-of-the-iceberg” moment.

Want a deep dive into the world of Streptomyces?  Here’s an article https://academic.oup.com/femsre/article/36/4/862/521102. 

Ain’t Nature Grand!!!

(So – Bee wolf, not Beowulf) (the BugLady has been waiting so long  to say that) (maybe not long enough?)

Kate Redmond, The BugLady

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

Bug o’the Week – Black-margined Loosestrife Beetle

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

All those spectacular flowers produce masses of seeds (a single plant’s output can be in the millions of seeds, annually).  In gardens and upland situations, they fall to the ground and they grow or they don’t and that’s fine – the seeds stay pretty close to the parent plant.  In wetlands, the seeds fall into the water and float away to colonize other corners of the marsh or pond edge or ditch.  At the start of the battle against the purple loosestrife invasion in the 1980’s, Montezuma National Wildlife Refuge, at the north end of Cayuga Lake in NY, an area whose massive cattail marshes historically supported a thriving chair caning industry, had become wall-to-wall loosestrife.

It’s hard to get people psyched up about whacking beautiful plants.  It frustrated the BugLady’s husband that as some people were working to get purple loosestrife banned, nurseries continued to sell it (he also worked hard on our county fair officials to ban its use in their flower arranging competition).  Somewhere there exists a photo of our oldest at age 5, decked out in her Purple Loosestrife Task Force tee-shirt, dwarfed by the bundle of loosestrife that she’s holding.  You get the picture.  In some states, including Wisconsin, it’s now illegal to buy, sell, or plant it, but seeds are available online. 

This is a story of (very carefully vetted) biological control. 

When purple loosestrife began taking over American wetlands, scientists visited the Old Country to identify the grazers that the plant had left behind, and they found three species of weevils and two leaf beetles (family Chrysomelidae), Galerucella calmariensis and G. pusilla – the “Cella” beetles.  The BugLady thinks that she photographed the Black-margined Loosestrife Beetle (Galerucella calmariensis) (BMLB) (some are “bandier” than others https://bugguide.net/node/view/399423).   

The BMLB’s native range is the Palearctic realm – Europe, most of Asia, and North Africa.  It was introduced to this side of the Pond in 1992, after an impressive testing regime that involved inviting the beetle to sample some 50 species of North American plants to see if it would stray to another food plant.  The tests were done in Europe instead of risking an escape here. In the tests, the Cella beetles vastly preferred purple loosestrife (they were mildly interested in our native Winged loosestrife (Lythrum alatum) in the lab, but preferred purple loosestrife in the field).  Since then, the beetles have been introduced in southeastern Canada and 27 Northeastern, Northwestern, and Upper Midwestern states, and they’re doing a fine job, indeed.  The two Cella beetles and two of the European weevils have been in play in Wisconsin since 1994.

Both the larvae and the adult BMLBs feed on purple loosestrife – the larvae on buds, shoots, and leaves (where they skeletonize the lower surface) (at a high density, the larvae alone can defoliate a plant), and the adults on the leaves, where their feeding causes a distinct “shot hole” defoliation.  Their one-two punch diminishes seed production and impairs photosynthesis, so that the plant stores less starch in its roots, killing or making them less vigorous.  As loosestrife plants decline, native plants can move back in. 

The biographies of the two species of Cella beetles are very similar, except for a small difference in timing – one species leads off, and the other bats cleanup.  According to bugguide.net, “N. calmariensis emerges about a week before N. pusilla, first eating the leaves, shoots, and buds; then the N. pusilla eats the new growth, weakening the loosestrife, and after a few years the plants die off.”

Adults eat, meet, and mate https://bugguide.net/node/view/2004790/bgimage on purple loosestrife, and females lay 300 to 400 eggs in batches on its stem and leaves.  They are not shy about striking out and finding new patches of loosestrife plants to colonize.  The larvae feed and then drop down and pupate in the soil (or in the plant stem, if the water is high), emerging as adults before the frosts to feed again.  Adults overwinter in the leaf litter at the base of the plants, emerging as the loosestrife starts growing again. 

Biological control of purple loosestrife isn’t quite as easy as tossing a bunch of Cella beetles out into a marsh and watching the loosestrife fade away.  The beetles are very susceptible to pesticides; they’re not attracted to loosestrife that’s growing in the shade or in high water; and a couple of species of lady beetles, a ground beetle, and a stink bug consider BMLBs delicious, slowing them but not stopping their spread.  According to the Cornell University (Go, Big Red!) College of Agriculture and Life Sciences’ Biological Control website, it’s estimated that once established, the work of the weevils and leaf beetles will reduce the loosestrife populations by about 90% over about 90% of its present range.  But it’s a long game – it may take three to five years (one source says seven to ten) for the beetles to build up to levels where they can significantly impact purple loosestrife. 

And the long, long game?  According to Reinartz’s Law of Biomass Availability, eventually native species will recognize that this vast mess of plants is edible (simply put – “If You Grow It, They Will Come”).

Check with the Wisconsin DNR for information about rearing Cella beetles for release https://dnr.wisconsin.gov/topic/Invasives/loosestrife.html.

Kate Redmond, The BugLady

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

Bug o’the Week – Lichen Moths

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Taxonomic Lumpers and Splitters have been working on the moths again.  Lichen moths (Hypoprepia sp) are in the Tiger moth family Arctiidae – or in the family Erebidae – depending on whose book you read.  Apparently, a bunch of moths in the Owlet moth family plus all of the members of the tussock moth and tiger moth families, plus a bunch of small families have been assigned to the family Erebidae, but Moth People are not 100% onboard with that yet, so stay tuned.  And, according to Wagner in Caterpillars of Eastern North America, “Adults of eastern Hypoprepia vary considerably in different parts of the Southeast, so much so that some lepidopterists feel additional species will eventually be recognized.” 

Lichen moth larvae https://bugguide.net/node/view/1483889/bgimage eat lichens and blue-green algae that they find growing on tree trunks.  As BugFans will recall from high school biology, lichens are a plant partnership – two plants growing symbiotically as one.  Structure, roots, and water are provided by a fungus “body,” and photosynthesis is carried out by algae that live within the fungus (or, as we Naturalists say – too often – “a lichen is a fungus and an alga that have taken a likin’ to each other.”).  Along with lichens, caterpillars have been reported to eat their smaller brethren and even LM pupae.  

Toxins from their veggies may make LM caterpillars poisonous to predators. The hairy caterpillars don’t come in startling warning (aposematic) colors (they look a bit like gypsy moth caterpillars http://bugguide.net/node/view/121849/bgimage), but the bright colors of the adults probably signal a non-tasty morsel within. 

Like the caterpillars of the Silver-spotted skipper butterfly (of previous BOTW fame), caterpillars in the genus Hypoprepia are able to fire their frass (bug poop) up to 30 body lengths away from themselves.  It’s called “fecal flicking.”  Why do it?  Some parasitic and predatory wasps track down potential prey by the scent of its frass, so the LM distances itself from its by-products.  Anal combs trap frass that’s coming down the pipeline and hold it until the “blood pressure” at the caterpillar’s tip becomes too great and the frass rifles out (the BugLady couldn’t make this up). 

LMs have some interesting sensory abilities, both as caterpillars and as adults.  Like typical adult tiger moths, LMs have “ears” located on their thorax.  They also make a variety of ultrasonic noises with organs on their thorax – this is an insect that can hear bats coming and, confident in its toxicity, sass them back, warning them against feeding on unwholesome LMs.  They also “vocalize” during courtship, and females have a pair of glands on the top of their thorax that crank out pheromones – chemical “scents” that lure males to them.  According to Sogaard, in Moths of the North Woods, caterpillars in the family are “typically densely hairy.  Some (perhaps all) caterpillars are sensitive to low-frequency sound through setae” (hairs). 

LMs overwinter as caterpillars, and adult LMs in this neck of the woods probably do not eat, though their tropical brethren do. 

The BugLady has been going happily bug-eyed trying to decide whether these are

SCARLET/SCARLET-WINGED LICHEN MOTHS or PAINTED LICHEN MOTHS or both (she suspects both).  SLMs are supposed to be very red and PLMs to have a yellowish cast, but she’s seen official pictures of each that stray into the other’s tint https://bugguide.net/node/view/2144967/bgimage, https://bugguide.net/node/view/853217/bgimage.  One reference suggests that SLMs have red heads and PLMs have yellow/gray heads (or maybe not).  At any rate, their lifestyles, ranges, and habitats (woodlands, east of the Rockies) are very similar, and these are two of only four species in the genus in North America.  Right now.

It has been suggested that adult PAINTED LICHEN MOTHS (Hypoprepia fucosa) mimic lightning beetles, which have toxic blood.

SCARLET LICHEN MOTHS (Hypoprepia miniata) are partial to lichens that grow on the trunks of red pine, and therefore gravitate to more coniferous woodlands (though they will nosh on lichens elsewhere if red pines aren’t available).  Miniata comes from the Latin word miniatus, which references lead-based vermillion or red paint.

Oh – and they have beauty!

Kate Redmond, The BugLady

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

Bug o’the Week – Great Blue Skimmer Dragonfly

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Great Blue Skimmers are common across the Southeast, but they wander north, sometimes as far north as Massachusetts, and rarely, Maine and Ontario.  One source referred to them as migrants, but that implies a return trip (only about 15 of the 331 North American dragonfly species are migratory (and a few of the damselflies roam a bit) – here’s the Xerces Society’s Guide https://www.xerces.org/sites/default/files/2018-05/12-036_01_MDP_Field_Guide_4-4-2013Websec.pdf).  In Dragonflies and Damselflies of the East, Dennis Paulson speculates that climate change may be allowing these skimmers to extend their range northwards, but he also wonders whether wet periods in the East may drive their episodic range expansions. 

Great Blue Skimmers (Libellula vibrans) are in the Skimmer family Libellulidae.  Members of the genus Libellula are called the King Skimmers – large, often flashy, aggressive dragonflies that dominate the sunny ponds where they live.  At almost 2.5” long, Great Blue Skimmers are the largest of the skimmers.  Their “plumage” changes depending on age and sex – young females https://bugguide.net/node/view/182934/bgimage and young males have yellow abdomens with a black stripe https://bugguide.net/node/view/1936981/bgimage.  Older females turn a dull brown with blue-ish to reddish-brown eyes https://bugguide.net/node/view/700746/bgimage, and mature males are a spectacular blue, with teal-colored eyes https://bugguide.net/node/view/787748/bgimage.  Like many dragonflies, the intensity of the adult colors is softened somewhat as it ages by tiny wax particles called pruinescence, which produce a hoary appearance.  They have white faces and pale, unstriped thoraxes https://bugguide.net/node/view/110122/bgimage, and the amount of black wrapping the tips of the wings is variable.   

Don’t look for them over sunny ponds with the other King Skimmers – these are dragonflies of the dappled sunlight of woodlands, edges, and roads through wetlands and bottomlands, where they may be the only dragonflies around.  They perch on twigs (at eye level and easy to photograph, said one source; at five to ten feet above the ground, said another).  

Males vigorously defend stretches of ponds that look like good spots for a female to oviposit – Great Blue Skimmers prefer shallow, wooded pools and ponds, swamps, ditches, and very slow-moving sections of streams (and there are reports of females ovipositing in muddy tire tracks).  Paulson says that they like “dark, mucky water.”  They mate (very briefly) https://bugguide.net/node/view/1664022/bgimage, and then he releases her, but he guards her from the air (“hover guarding”) and shoos away rival males as she lays eggs. 

She has a unique approach to ovipositing – she flies down to the water’s surface with eggs at the ready (scroll way down for a picture of eggs https://www.marylandbiodiversity.com/view/740), then she dips down and uses her abdomen to scoop and splash a bit of water, plus eggs, up to six inches away (“She may splash eggs and water onto the bank, presumably for a rainy day,” says Legler, in Dragonflies of Wisconsin).  Watch the video to see her technique https://waltersanford.wordpress.com/2012/07/16/great-blue-skimmer-dragonflies-mating-pair-fe/.  The drops of water are thought to help the eggs adhere to land.  When the eggs hatch, the tiny naiads crawl into the water.    

As always, both the aerial adults and the aquatic naiads are carnivorous – the adults spot their insect prey from perches in the shade and fly out to grab it, a behavior called “hawking,” and their menu includes smaller dragonflies. 

The BugLady doesn’t care how common this dragonfly is within its range, it distresses her to find ads offering pinned specimens for “$40 to $60 depending on quality and sex” (which also sounds caveat emptor-ish to her). 

The BugLady attempts a lot of Hail Mary Shots of dragonflies in flight (in fact, a recent shot of distant Common Green Darners flying in tandem seems to have an equally-distant Great Blue Skimmer in it), but most of them end up on the cutting room floor.  She’d like to give a shout-out to this one https://bugguide.net/node/view/231364/bgimage.  

Kate Redmond, The BugLady

And speaking of rare Lepidopterans – heads-up in the Pacific Northwest: https://www.smithsonianmag.com/smart-news/first-us-sighting-of-massive-atlas-moth-confirmed-180980617/?utm_source=smithsoniandaily&utm_medium=email&utm_campaign=20220822-daily-responsive&spMailingID=47269440&spUserID=ODg4Mzc3MzY0MTUyS0&spJobID=2302313711&spReportId=MjMwMjMxMzcxMQS2

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

Bug o’the Week – Rose Chafer Beetle

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Rose chafers can be found in grasslands, gardens, and viney edges over much of eastern North America as far west as Colorado and Montana, although distribution gets spotty the farther South you get. They especially like sandy areas (more about that in a sec).  Bugguide.net considers the western records to be “iffy” because of the possibility of confusing the Rose chafer with one of the other two species in the genus Macrodactylus that live north of Mexico (https://bugguide.net/node/view/939033/bgpage, and https://bugguide.net/node/view/1253988/bgimage), but insects can find an infinite number of ways to hitchhike.

They’re about a half-inch long (females are bulkier than males), covered with yellow hairs that rub off with age (or in the case of the female, with mating), exposing the dark cuticle beneath.  The official name for their antennae is “lamellate,” which means “plate or leaf-like” https://bugguide.net/node/view/110081.  The legs are spiny and the feet/tarsi are clawed (all the better to hang on with, my dear) https://bugguide.net/node/view/1275119/bgimage.  Several sources said that the beetles may resemble a wasp while in flight (maybe because of the dangling legs?).

The BugLady does not garden.  She puts her geraniums out on the porch in May, waters them when she thinks of it (they’re very patient), and hauls them back in at the end of October, at around midnight as the first killing frost is descending, and she wouldn’t know what to do with a rose bush if she had one.  Rose chafer beetles feed on the leaves and flowers and maybe the nectar and pollen of lots of different kinds of plants.  Their jaws are weak, so they eat the tender tissue between the leaf veins, skeletonizing the leaf; they make holes in petals; and they eat soft fruits like raspberries and grapes. 

Some sources say that the beetle is only a slight nuisance, doing mainly cosmetic damage; others give instructions for all-out warfare.  Their populations wax and wane, and when there’s a Rose chafer population boom, the beetles may consume a substantial portion of a leaf’s photosynthetic surface and may also impair pollination.  Plus, they may feed in groups.  Interestingly, the North Carolina State Extension write-up about Rose chafers calls them a “relatively minor pest of roses that at one time was apparently much more abundant.”

With many insect “pests,” it’s the larvae that do the most damage, but with the chafers, it’s the adults who are the problem.  Rose chafer larvae feed underground on the roots of grasses and other plants, and although a bumper crop of larvae can stunt a plant, they don’t seem to be a real threat to turfgrass or ornamentals. 

Rose chafers can be seen during June and July here in the North.  The plants that they feed on also serve as Social Clubs where males and females meet and mingle https://bugguide.net/node/view/265114/bgimage.  When this “What’s going on here?” picture https://bugguide.net/node/view/120287/bgimage was posted on bugguide.net, entomologist Eric Eaton responded “I don’t think they are ‘eating’ the milkweed. This kind of aggregation is usually associated with mating or “sleeping.”  This seems to be another example of insects chewing on plants; plants releasing volatile compounds to discourage that; and those compounds, perversely, attracting a crowd.  The Rose chafers use their antennae to key in on those plant “odors.”

The female oviposits in the soil, digging down as far as six inches below the surface (!!!), which is why she prefers plants that grow in sandy soil.  She may lay from six to forty eggs, and when they hatch in a few weeks, the larvae locate roots to feed on.  They will move up and down in the soil, depending on soil moisture and soil temperature, and they will overwinter deep in the ground, below the frost line, moving up toward the surface to pupate when the earth warms in spring. 

Many of the scarabs are nocturnal, but Rose chafers are abroad during the day.  They are strong fliers.

Rose Chafer Surprise:  Rose chafers produce cantharidin, a caustic chemical mainly found in beetles in the blister beetle family Meloidae (see https://uwm.edu/field-station/blister-beetle/)!  Although the author of one gardening blog noted that he had been picking them off of plants for decades with no ill effects (the skin on our fingers is pretty tough), he joined the chorus of authors who stressed that the beetles are poisonous to chickens and other birds.

In his “Living with Insects” blog, entomologist Jonathan Neal explains “Their toxicity to chickens led to one of the early scientific studies of toxins in insects. In 1909, George Lamson, Jr, of the Connecticut Agricultural Experiment Station investigated reports of a flock of chickens that died after feeding on the abundant Rose Chafers. Lamson fed Rose Chafers to chickens and determined the numbers required to kill week-old (15-20 Chafers) and 3-week-old chickens (25-45 Chafers). In the early 1900s, chickens were commonly allowed to range free and could easily consume large numbers of Rose Chafers in years with high populations. Lamson recommended that chickens be excluded from areas that contained large numbers of Rose Chafers.  Lamson made an extract of Chafers and demonstrated that the extract was toxic to both chickens and rabbits. These tests proved that the deaths were due to a chemical toxin and not a physical effect from the insect spines or other physical properties. Lamson reported his findings in the Journal “Science” in 1916.”

Kate Redmond, The BugLady

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

Bug o’the Week – Mid-summer Scenes

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

ARROW CLUBTAIL:  In early July, the BugLady came across this just-emerged dragonfly sitting on a stalk in the Milwaukee River.  She photographed it for half an hour as it lengthened and strengthened and spread its wings and grew its abdomen.  She guarded it from marauding geese and grackles.  And she watched as it took its maiden voyage, eight feet straight up and true – into the beak of a swooping Cedar Waxwing.  She may have used a few bad words. 

JAPANESE BEETLE   Precarious as this bundle of beetles looked, it kept its shape as it fell off and into the grasses.  In order to jump-start her love life, a female Japanese beetle may use “come hither” pheromones, but this aggregation of beetles was probably initiated (inadvertently) by the plant itself.  Research suggests that a female Japanese beetle chewed on a leaf, and the leaf gave off signature chemicals (OK – feeding-induced plant volatiles), and that instead of repelling the beetles, the scent attracted more beetles, both male and female, to feed.  And, since all those guys and gals are in the same neighborhood……… 

MAYFLY MOLT:  BugFan Freda sent this amazing “What-is-it?” picture recently, taken from a canoe on the Milwaukee river.  Mayflies (called “lake flies” regionally) emerge from their watery cradles by the googol.  Their lives are brief, averaging only three days (not coincidentally, the name of the mayfly order is Ephemeroptera).    

Mayflies are the only insects that shed their skins after they reach the winged adult stage (silverfish shed as adults, too, but they’re spindle-shaped and wingless).  The mature mayfly naiad https://bugguide.net/node/view/517056/bgimage crawls out onto a plant or rock and sheds its final skin (exuvia), emerging as a form called a subimago (or a “dun” if you’re a fly fisherman) that is cloudy-winged, dull in color, weak-flying, and not ready to reproduce.  The sub-imago rests (often overnight) and then sheds again, this time into a mature adult/imago with shiny wings (a “spinner” to fishermen).  Here’s a typical adult/imago https://bugguide.net/node/view/933725/bgimage.  No – scientists do not know how this pre-adult stage benefits the mayflies – lots of insect groups apparently has a subimago stage in ancient times, and most have dropped it from their repertory. 

Freda’s picture shows the exuviae of lots of sub-imagoes – it must have been an amazing sight to see!  Scroll down this series of pictures of that final shed – http://www.troutnut.com/article/10/pictures-of-mayfly-dun-molting-to-spinner.  

DOGBANE LEAF BEETLE:  Its fabulous, shimmering exterior is all done with mirrors (complex nanoarchitecture).  Light is bent when it hits small, randomly-tilted plates that sit between the pigment layer and the top layer of the beetle’s cuticle, and the beetle’s color changes depending on the angle of the eye of the beholder.  What good is that glow?  Rather than being an aid in courtship or a warning of the beetle’s toxicity (and this particular beetle is, but not all iridescent insects are), this fiery iridescence actually camouflages it.  To test the hypothesis, researchers disguised meal worms with beetle elytra (the hard outer wings) – some shiny and some not – and then hid them.  Birds found and ate 85% of the “dull-winged meal worms,” but only 60% of the “iridescent meal worms,” and the scientists themselves found it difficult to locate the shiny ones. 

STREAM BLUET AND MAYFLY: In order to make it to adulthood, a mayfly naiad must avoid being eaten by fish and a variety of insects during its aquatic stage, and by fish, birds, fishing spiders, frogs, and other predators as it completes both of its molts.  When it takes to the air, more predators await.  This mayfly became lunch for a Stream Bluet damselfly.  

DOODLEBUG:  The BugLady found this doodlebug on the dunes at Kohler-Andrae State Park in mid-July, plying its trade.  She looked into lots of inverted, sandy cones before she found one that held prey – in this case, a small spider.  The doodlebug will grow up to be an antlion https://bugguide.net/node/view/1708468/bgimage.  For an account of the life of a doodlebug, see https://uwm.edu/field-station/spotless-antlion/.  

SAWFLY:  Sawflies are not flies, but are primitive wasps with no stingers (as she did when she wrote her first episode about sawflies in 2009 https://uwm.edu/field-station/sawfly/, the BugLady recommends reading the sawfly chapter in David W. Stokes’ excellent A Guide to Observing Insect Lives).  Sawfly larvae look a lot like butterfly and moth caterpillars, but there’s a difference in the arrangement and types of legs.  This beauty just might be the Poison ivy sawfly (Arge humeralis), whose pretty cute offspring the BugLady is going to have to keep a cautious eye out for https://bugguide.net/node/view/826616/bgimage.  “Sawfly” because the female uses a saw-like structure at the end of her abdomen to cut slots in vegetation to lay her eggs in.

BLACK SWALLOWTAIL CATERPILLAR: While the BugLady was photographing the sawfly, she noticed a prickly head among the Queen Anne’s lace florets, so she bent the stem sideways to see what it was.  There was a cute little jumping spider under there, too, which she hoped did not have designs on the caterpillar.  Black Swallowtails lay their eggs on plants in the carrot family, and most gardeners who plant dill are familiar with them (and, the BugLady hopes, are generous enough to share). 

BLUE MUD DAUBERS are all over the Queen Anne’s lace these days.  Adults cruise the flower tops, sipping nectar and looking for spiders to cache in the egg chambers of their offspring, who will grow up on protein but eschew it as adults.  Sometimes the wasps pick spiders right off of their webs, and they especially like to collect Black widow spiders (which are here in God’s Country but are rare https://bugguide.net/node/view/1876965/bgimage).  They grab spiders with their mandibles https://bugguide.net/node/view/1268654/bgimage and paralyze them with a sting, but they don’t bite people, and you have to rough one up considerably before she’ll sting you.

EMERALD ASH BORER:  The BugLady loves ash trees, but these days, the landscape is littered with their skeletons.  The first Emerald ash borer was detected in Wisconsin in Ozaukee County during the summer of 2008, though the EABs had undoubtedly been around for a few years before that.  The picture shows an ash that is fighting for its life, a battle that it will not win.  The top of this ash is dead, because the EAB larvae’s tunnels (galleries) just below the bark interfere with the flow of nutrients between the crown of the tree and its roots.  The stressed tree responds by growing a bunch of shoots (called epicormic sprouts) from dormant buds in the bark of the trunk.  The leafy sprouts, which are below the EAB damage, will allow the tree to photosynthesize – for a while.  Read about EABs in a previous BOTW.https://uwm.edu/field-station/emerald-ash-borer-redux-family-buprestidae/.  EABs are, undeniably, beautiful beetles https://bugguide.net/node/view/1770902/bgimage, https://bugguide.net/node/view/1233730/bgimage, https://bugguide.net/node/view/938332/bgimage. 

SIX-SPOTTED FISHING SPIDER:  Moving from a “solid” water lily leaf to a liquid substrate is no trick at all for a Six-spotted Fishing spider (the six spots that give it its name are on its underside) – in fact, it has more moves on the water than it does on dry land.  It can walk, run, sail, or skate over the surface film and can dive under it, too. 

GIANT SWALLOWTAIL: If there’s anything more stunning than a couple of Giant Swallowtails dancing in the air over purple coneflowers, the BugLady doesn’t know what it is. 

Kate Redmond, The BugLady

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

Bug o’the Week – Cuckoo Leafcutter Bee

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Within the Megachilidae, the tribe Megachilini contains the genus Coelioxys – the Cuckoo leaf-cutter bees, aka the Sharp-tailed bees (Coelia means “belly” and “oxys” means “sharp”).  The Coelioxys aren’t the only bees that are “cuckoos,” a term that refers to bees that lay their eggs in another bee’s nest; Rusty Burlew, on the Honey Bee Suite website, tells us that 20% of all bee species are nest parasites (another source put it at 15%) and that this behavior occurs in most bee families (which means, he says, that there’s “a whole lot of poaching going on”).  

The host bees aren’t just babysitting.  Cuckoo bees are “kleptoparasites” (kleptoparasitism means “parasitism by theft”).  Their offspring take advantage of the work of the nest-building/host female, eating the food stores she has collected and killing their rightful owner.  There are 46 species in the genus Coelioxys, and each species targets different species of bees, mostly from within their own Megachilidae family.  

Because they no longer make nests for their young (one website suggests that they’ve been nest parasites for so long that they’ve forgotten how), they are minimally-hairy (oddly, they have hairs on their eyes), and they lack the dense, pollen-collecting hairs under the abdomen that many leaf-cutting bees sport https://bugguide.net/node/view/30569/bgimage.  For that reason, they’re not good pollinators.   

One website says that “Cuckoo leafcutter species appear very similar to the casual observer, and species identification is often best left to an expert,” and the BugLady plans to take that advice (for a change).  Females have pointy abdomens https://bugguide.net/node/view/1593995/bgimage, and males’ abdomens are toothed https://bugguide.net/node/view/2050487/bgimage.  Most of our northern species are basic black with white lines, sometimes with red in the legs, but some Southern species are fancier – https://bugguide.net/node/view/1616384/bgimage, https://bugguide.net/node/view/2093977/bgimage, https://bugguide.net/node/view/1409086/bgimage.  Most are less than a half-inch long.   

Female Cuckoo bees are bee-watchers; they visit flowers to sip nectar, but also to spy on potential hosts and follow them back to their tunnels.  When its owner leaves, looking for more pollen, the cuckoo bee enters the tunnel and uses the sharp tip of her abdomen (a modified stinger) to puncture the leafy walls of an egg chamber and to lay her eggs inside.  Her larva will use its sickle-shaped jaws to bisect the host egg or larva, and it will kill any of its own siblings in the chamber.  It pupates in the egg chamber, and its emergence the following year will be synched with the flight period of its host.

Fun Facts about Cuckoo Leafcutter bees:

  • The genus name is pronounced “seal-ee-OX-ees.”

FOR THE RECORD: to every author out there who likened the actions of cuckoo bees to cuckoo birds (family Cuculidae), a clarification.  New World species of cuckoos (except for three species in South America) build their own nests and care for their own young; some (but not all) Old World members of the cuckoo family (the 56 members of the subfamily Cuculinae, the Parasitic cuckoos) are, famously, brood parasites.  The difference between a nest parasite and a brood parasite is that brood parasites, like our Brown-headed Cowbird, leave their eggs in other birds’ nests with the expectation that the adoptive parents will raise their young.  This often comes at the expense of the nest-maker’s brood, since the cowbirds hatch first, grow fast, monopolize the feedings, and may elbow the other chicks out of the nest. 

Kate Redmond, The BugLady

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

BREAKING NEWS: in another fit of Political Correctness, the Entomological Society of America has renamed the Asian giant hornet, aka the Murder hornet, (a hornet that is, indeed, from Asia) “in an effort to reduce negative and nationalistic associations.”  It’s now the Northern Giant Hornet.  The BugLady supposes that the Asian multicolored ladybug will be next, but as BugFan Mike suggests, maybe the Negro bug https://bugguide.net/node/view/5184, nominally in the Ebony bug family, should come first.  

Bug o’the Week – A Tale of Two Butterflies – Part 2 – Marine Blue

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

Its normal range is the scrublands and deserts of southwestern of North America, south into Mexico and Central America, but it shows up as an “emigrant” elsewhere http://mothphotographersgroup.msstate.edu/species.php?hodges=4357.  Wisconsin has had at least seven records so far this summer, one on the west side of the state, one in Madison, and the rest in Ozaukee and Sheboygan Counties, on the east side (Wisconsin butterfly watchers are a dedicated community). 

In The Butterflies of Iowa (2007), Schlicht, Downey, and Nekola pose an interesting question.  Marine Blues spend only 5 to 10 days as adults.  How does such a short-lived butterfly get from, say, Arizona to Iowa?  Or Wisconsin, or Ohio, or New York?  They speculate that it may be transported in shipments of alfalfa. 

It’s an ecologically flexible species, which is a recipe for success.  Marine Blues inhabit the Southwestern deserts, but they’re also at home in tropical lowlands, conifer forests, higher altitudes, open/disturbed/”weedy” areas, urban gardens, and agricultural fields.  There are plenty of species of food plants available for both the adults and the caterpillars.    

Marine Blues (aka Striped Blues or Marine Striped Blues) are in the Gossamer-winged butterfly family Lycaenidae (Blues, Coppers, Hairstreaks, and Harvesters).  Samuel Scudder (19th century entomologist and paleontologist and insect namer) called the genus Letotes the “banded blues.”  Like other blues, they’re small, with a wingspan of a little over an inch.  Males and females have similar “tiger-striped” underwings; the upper wings of males have a purplish tinge https://bugguide.net/node/view/1450319/bgimage (the BugLady didn’t find an explanation of why a desert butterfly was named the Marine Blue, but it must have been a nod to the male’s color).  The blue on the females is restricted to the base of the upper wings, which often show grid-like lines that echo the pattern of stripes on the underwing https://bugguide.net/node/view/411840.  

As always, blue pigments are extraordinarily uncommon in animals; most blue is a trick of the light.  In butterflies, it’s a result of light being bent/diffracted by the “complex nanoarchitecture” in the cuticle of the scales that cover the butterfly’s wings (for a deeper dive, see “Butterflies Hack Light Waves” https://asknature.org/strategy/wing-scales-cause-light-to-diffract-and-interfere/).

Their flight is fast and erratic.  Males actively patrol for females, the male flashing his wings and “calling her” with pheromones https://bugguide.net/node/view/716954/bgimage.  Her response to him includes an assessment of the “nutritional abundance of the environment”.  She ultimately lays eggs on the flower buds of legumes.    

The variably-colored, slug-like caterpillars eat the flower buds and developing flowers and seeds (but never the leaves) of woody and herbaceous, wild, agricultural, and ornamental plants in the Pea/Legume family – plants like Acacia, Mesquite, vetch, prairie clover, sweet pea, trefoils, wisteria, and alfalfa.  The caterpillars eventually form a chrysalis in the litter below their host plants https://bugguide.net/node/view/2114148/bgimage.  They produce multiple/continuous broods in the far south.   

Adults get nectar from a variety of flowers – some legumes and some not – and sip other nutrients from dung and from damp soil https://bugguide.net/node/view/675418/bgimage.  Here are some great shots of various life stages: http://leps.thenalls.net/content2.php?ref=Species/Polyommatinae/marina/life/marina_life.htm.     

Like other family members, Marine Blue caterpillars are myrmecophiles – they form close associations with ants.  Ants protect them from parasitoids (insect larvae that would eat them alive) in exchange for honeydew produced by the caterpillar. 

Marine Blues are common throughout the Southwest, but their population in Southern California has gotten an unexpected bump (the Snout had “dominoes,” and so does the Marine Blue).  There, Marine Blues have become urban butterflies – one source says that they’re the most common butterfly in Orange County, California!  In a paper that appeared in the Journal of the Lepidopterists Society in 1990, entomologist John Brown explains that the Marine Blue has been a common backyard butterfly in Southern California, where wisteria has been its favored host plant, since the 1920’s.  But the butterfly has jumped to a new, non-legume host, a South African evergreen shrub called Cape Plumbago (Plumbago auriculata), which is widely planted in landscaping and along roadways and blooms year round. 

The ant in the Marine Blue-ant partnership is the Argentine ant (Linepithema humile, formerly Iridomyrmex humilis), a pretty interesting species that forms super colonies over vast areas (https://en.wikipedia.org/wiki/Argentine_ant) and that balances the negatives of routing native ant species and being a persistent home invader with the positives of eating mealybugs and scale on citrus.  Brown noted that “Leptotes marina is one of few native North American butterflies that has benefited from the activities of man by its remarkable switch to a new larval host introduced from South Africa and to a nectar source and an ant introduced from South America [the butterflies strongly favor the introduced Brazilian pepper flowers for nectaring], none of which are closely related to the butterfly’s native resources. This flexibility undoubtedly has led to an expansion in range, at least ecologically and temporally, over the past 60 years, resulting in the butterfly’s invasion and successful colonization of urban environments.”

So – another day, another Southwestern visitor, but unlike the American Snout, there don’t seem to be a set of precipitating factors for Marine Blues’ wanderings (other than northbound truckloads of hay).  And, unlike the Snout, Marine Blues (probably) do not produce broods at the ends of their journeys.  

Thanks to BugFan Freda for the use of her beautiful picture of a mint-condition Marine Blue sitting on a clover. 

Kate Redmond, The BugLady

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

Bug o’the Week – A Tale of two Butterflies – Part 1 – the American Snout

Bug o’the Week

Sanborn’s Beewolf

Howdy, BugFans,

Ever since she read about beewolves years ago, the BugLady has been hoping to photograph one so she could tell its story.  She finally found one in the dunes at Kohler-Andrae State Park, and no – the Rose chafer beetle in the picture has nothing to fear from it, and vice versa.

Beewolves are small, solitary, mostly black wasps in the family Crabronidae, which we have met before in the person of Square-headed and Sand wasps.  Our beewolf species look a lot alike (and they resemble a lot of other small, solitary wasps, too), but the BugLady thinks that this is a Sanborn’s beewolf (Philanthus sanbornii).  They’re ½” to ¾” long (females are larger than males).  Here’s a glamour shot https://bugguide.net/node/view/127735/bgimage.

The Snout

She was walking along the river when she saw an orange and brown butterfly fluttering around near a bare area.  Even though she hadn’t seen one for a long time, she was pretty sure she knew what it was (having quickly eliminated from consideration the slightly larger and more vividly-colored Red Admiral, American Lady and Painted Lady). After that first encounter, she saw several more Snouts.

Some taxonomists put them in the Brush-footed butterfly family Nymphalidae, within the subfamily Libytheinae (Snouts), and others put them in their own family Libytheidae (the Snouts or Long Beaks).  There are only about eight species of snouts worldwide, all in the tropics/subtropics, and although older field guides may list several species of American Snouts, they’re presently lumped into a single species that’s divided into races, geographically.  The Libytheidae are “old-timey” butterflies, whose fossilized ancestors have been found in 35 million year old deposits.  It’s possible that earlier generations had some use for that snout that we haven’t figured out. 

Nymphalidae is a family in which the butterfly’s front legs are greatly reduced and brush-like – essentially, they are four-legged butterflies.  American Snouts (Libytheana carinenta) have tweaked that design; males get around on four legs, but females have six functional legs.  Their “snout” is actually a pair of elongated mouthparts called labial palps https://bugguide.net/node/view/1542556/bgimage (the species name “carinenta” comes from a Latin word for “keel” and alludes to the shape of the palps). 

When they’re perched, Snouts are pretty distinctive.  With angular, variously-leafy-looking underwings https://bugguide.net/node/view/1885500/bgimage, https://bugguide.net/node/view/1253002/bgimage, https://bugguide.net/node/view/725354/bgimage, https://bugguide.net/node/view/709384/bgimage, and a head that looks like a leaf stem, they are well camouflaged.  If they’re alarmed, they may flick open their wings and startle predators with a flash of orange.  Their wingspread is about 1 ½ to 2 inches, and males and females look similar.   

They’re found in open woods, especially near wetlands and streams, from Argentina into our Southern tier of states, where they produce multiple broods a year and overwinter as adults.  They wander north of their regular range (as far as Ontario, but not to the northwestern quadrant of North America), and they sometimes undertake dramatic movements (more about that in a sec). 

Snouts visit Wisconsin most years (no sightings in 2021, but good numbers this year), arriving in late spring and producing a brood, with their numbers peaking in July.  Our winters are (still) too cold for them to overwinter.  Early arrivals to the North Country will bask in the sun for warmth, and they can quiver the (internal) flight muscles to generate some heat for flight (muscular thermogenesis).

These are not really migrants – some authors call them “immigrants” – because there’s no corresponding southward movement in fall by subsequent generations.  In Butterflies of Wisconsin (1970) Ebner says “Hoy stated the curious insect was once common in the Racine area but that it had dwindled drastically in abundance by 1881.”    It is conceivable that the species is short-lived here and exterminated by a severe and prolonged winter season.”  Snouts are more common in the southern part of Wisconsin because there are more of the caterpillar host trees in the south.

Their lives are tied to hackberry trees.  Males patrol for females near hackberries.  Several sources noted that mating pairs https://bugguide.net/node/view/234642/bgimage have been seen at dusk and at night, suggesting that they are crepuscular breeders, but others say that mating occurs at any time of day.  Females lay eggs in the hackberry leaf axils, and the caterpillars https://bugguide.net/node/view/1567718/bgimage (older caterpillars are fancier https://bugguide.net/node/view/6528) hatch and feed on the leaves.  Development is speedy – from egg to adult in just over two weeks!  The University of Florida Entomology and Nematology’s “Featured Creatures” blog adds this wonderful side note: “When not feeding, larvae in Brazil are reported to rest on frass chains as a defense against predators.”

Because their proboscises are short, adults feed on nectar from “shallow” flowers like dogbane, aster, and goldenrod (the BugLady photographed one on Nannyberry), and they also get nutrients from bird droppings.  Males use their proboscises to absorb minerals from mud puddles.

Sometimes, the dam bursts and there are Biblical movements of Snouts throughout the Southwest – For this to happen, a few dominos have to line up.  The first domino is drought.  Snouts go into a state of diapause (become inactive) during a drought. 

The second is heavy, summer rain – when the drought breaks, the rain stimulates Spiny hackberry trees (but not other hackberry species) to grow tender, new leaves. 

Third, during a drought there are fewer insects like this Chalcicid wasp https://bugguide.net/node/view/1179366 that might be parasitoids of the caterpillars, so higher numbers of caterpillars survive. 

It’s the perfect storm – the rains come, the Snouts wake up, and the landscape is covered with butterflies that are eager to breed.  There are, suddenly, lots of places to lay eggs, and lots of leaves for caterpillars to eat, and the population explodes.  Professor Larry Gilbert found hackberries one meter in diameter with upwards of 4,000 chrysalises on them https://bugguide.net/node/view/6527/bgimage, https://bugguide.net/node/view/234621/bgimage (this one holds an almost-mature butterfly!).  Gilbert estimated that in 1978, the number of Snouts produced on the Chaparral Wildlife Management Area in Texas was about one-half billion (get the full story here http://texasento.net/snout.htm).

After the caterpillars defoliate the hackberries and metamorphose into adults, the Snouts spread out, moving at five to eight miles per hour, looking for more hackberries, hopscotching from one suitable spot to the next   Clouds of butterflies block the sun, lower visibility on the interstate, gum up windshields and radiators, and cause street lights to go on!  You would think that there would be a bunch of images of this on the internet, but there aren’t.

And here’s an excerpt from an article in the Texas Parks and Wildlife publication by Ben Hutchins, about an earlier event: “In 1921, an estimated 75 million butterflies per hour passed through South Texas in a particularly large wave that stretched for nearly 250 miles. To put that in perspective, the entire eastern monarch population during the winter of 2016-2017 was estimated at just over 81 million individuals. That’s essentially every monarch in North America east of the Rockies, save for a few snowbirds that hang out around the Gulf Coast, compared to 75 million American snouts passing by in a single swarm, in a single hour. The flight lasted for 18 days.”

The wonderful Butterflies of Massachusetts account reports that Snout sightings had increased in New Jersey and New York by the end of the last century, which suggests that their range could expand northward as the climate warms.

It’s not too late to see one this year.

Kate Redmond, The BugLady

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

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