Bug o’the Week – Summer Sights – and Sounds

Bug o’the Week
by Kate Redmond

Summer Sights – and Sounds

Howdy, BugFans,

The BugLady took to the trails this summer as much as her shiny, new knee and the oppressive heat and humidity allowed (her preferred maximum temperature is 72 degrees.  The gods didn’t cooperate).  Here are some of the bugs she found.

BLUE DASHER OVIPOSITING – A female Blue Dasher bobs up and down as she looses eggs into the water.  Blue Dashers don’t oviposit “in tandem,” with the male guarding her by maintaining his grip at the back of her head, but the male stays close, flying around her as she dips the tip of her abdomen into the water, and chasing off rival males that would carry her away.

CICADA – When the BugLady was little, the treetops sizzled with cicada calls in August (she called them “hot bugs,” because when they emerged, it was).  The only species she heard back then was the dog day cicada https://uwm.edu/field-station/bug-of-the-week/dogday-cicada-family-cicadidae/, but for the past decade, she has heard fewer and fewer of them each year https://songsofinsects.com/cicadas/dog-day-cicada.  

This year, she has been enjoying the songs of a Linne’s cicada https://songsofinsects.com/cicadas/linnes-cicada and an dusk-calling Scissor-grinder cicada https://songsofinsects.com/cicadas/scissor-grinder-cicada, too, both of whom are southern/southeastern species that are inching north.  Welcome!

CABBAGE BUTTERFLY ON PURPLE LOOSESTRIFE – A dainty, white butterfly on a pretty, fuchsia flower.  Both are non-native (hint: the butterfly’s caterpillar is known as the European cabbage worm), and both are “naturalized,” that is, having been introduced and/or having escaped into the wild, they are doing very well on their own, thank you.  Only a very small percentage of non-native, naturalized species go on to create problems and to get a third label – “invasive.”  For a nice discussion, see https://www.hrwc.org/invasive-non-native-or-naturalized/

EASTERN PONDHAWK AND MEADOWHAWK – It’s a dragonfly-eat-dragonfly world out there.

MILKWEED TUSSOCK MOTH AND CRAB SPIDER – The BugLady has been receiving some queries recently from BugFans whose milkweed is looking pretty ratty.  The culprit?  The Milkweed tussock moth https://bugguide.net/node/view/72813, whose caterpillar is sometimes called the Harlequin caterpillar.  Mom lays masses of eggs, and the caterpillars feed gregariously for a while, skeletonizing leaves by eating the tender tissue between the leaf veins.  Then they go their separate ways and eat the leaves down to their midribs.  Bugguide.net says, in an understatement, that the caterpillars “May defoliate patches of milkweed.” 

Allegedly, they don’t interfere with Monarch caterpillars because they eat the old, leathery leaves that the monarchs don’t, and because they’re gearing up as the Gen 5 Monarchs are readying themselves for their trip south.

No, the BugLady did not see the crab spider, and what looks like an egg sac, when she took the picture.

PICTURE-WINGED FLY – This spiffy fly (genus Rivelli, family Platystomatidae) walks around, twitching its wings constantly, sending semaphore signals to nearby females.  For its story, see https://uwm.edu/field-station/bug-of-the-week/signal-fly/ (only, the BugLady misspelled the family name).  What a treat to watch this little fly strutting his stuff!

WOOD/AMERICAN DOG TICK – Yes, they’re everywhere (they prefer grassy areas and forest edges), and yes, most people feel creepy just looking at a picture of one, feeling the phantom feet of phantom ticks tickling their skin.  Dog ticks need three different hosts to get through their life cycles, and they can spread Rocky Mountain spotted fever as well as Tularemia (but if your dog comes down with Tularemia, it may be playing with the local bunnies).  Various sources say that Wood ticks in Wisconsin don’t often carry diseases and that Rocky Mountain spotted fever (or any Spotted fever rickettsiosis) are (for now) rare here.  They don’t spread Lyme disease.

VIRGINIA CTENUCHA CATERPILLAR –Lepidopterists say that the more spectacular the caterpillar, the more homely the adult, and vice versa  The Virginia Ctenucha moth is one of the exceptions that proves the rule https://bugguide.net/node/view/1991557/bgimage.

The caterpillars are out and about early – this one was photographed in May, but they overwinter as caterpillars, and the BugLady encounters them strolling along on the warm road on a warm day in late winter or early spring.  Adults are large-ish, day-or-night-flying moths that tuck in under a leaf when alarmed.  The “C” is silent. –

WOOLLY ALDER APHIDS AND THEIR ANTS – We’ve seen it before – aphids going about their business, assisted by ants that protect them them in exchange for being able to “milk” them for honeydew, a sugary fluid that is a byproduct of the sap that flows through the aphids when they eat.  Honeydew is an important carbohydrate for the ants that farm aphids and treehoppers.  If you’ve ever seen a leaf whose upper surface looks shiny and sticky, look up under the overhead leaves – they’re probably occupied by aphids.  Bees, wasps, flies, and other insects will visit the leaf to eat honeydew.  The woolly aphid’s wool consists of waterproof, waxy filaments made in glands in the aphid’s abdomen.

EMERALD ASH BORER – They really are lovely, little beetles, with a surprise splash of crimson when their wings are spread https://bugguide.net/node/view/1522143/bgimage.  But the extensive tunnels (called galleries https://bugguide.net/node/view/687825/bgimage) that the larvae make below the bark disrupt the ash tree’s plumbing so that it can’t pump nutrients between its roots and crown. 

SEDGE SPRITES – One of the BugLady’s favorite damselflies, these little beauties are scarcely an inch long. 

WEEVILS ON PURPLE PRAIRIE CLOVER – Purple prairie clover is a lovely, native tallgrass prairie plant.  The early settlers on the Great Plains nicknamed it “Devil’s shoelaces” because this skinny, two-foot-high plant may have roots that are six feet long – roots that grew deep enough to reach through the thick prairie sod to find water.  That magnificent sod resisted the settlers attempts to plow it with their small, cast-iron plows until 1837, when John Deere invented the steel moldboard plow, which he fashioned from an old sawmill saw. 

At the top of the flower, there are two weevils, probably seed weevils in the genus Apion, making whoopie.  Here’s a BOTW about seed weevils https://uwm.edu/field-station/bug-of-the-week/baptisia-seed-pod-weevils/.  No, the BugLady did not see the weevils when she took the picture.  

STAG BEETLE – Yes, the BugLady did see this Stag beetle as it emerged from her lawn one evening in July – the beetle looks big enough to trip over, and she moves like a tank.  Here’s her story https://uwm.edu/field-station/bug-of-the-week/stag-beetle-lucanus-placidus/.

ROBBER FLY – Remember, bumble bees are vegetarians, so if you see a bumble bee with prey, it’s not a bumble bee.  Mimicking a bumble bee is a pretty good survival strategy – no one messes with bumble bees.  This fly is in the genus Laphria, one of the “bee-like” robber flies.  Their larvae live in rotten wood and feed on insects they find there, and the adults often prey on beetles (though the BugLady saw one make a pass at a Sulphur butterfly once).  Robber flies come in a variety of sizes and shapes – for information about Wisconsin robber flies (and butterflies and tiger beetles) see https://wisconsinbutterflies.org/butterfly.

RED-BELTED BUMBLE BEES – are found west of the great plains and across southern Canada and our northern tier of states.  They are one of the short-tongued bumble bees, which means that they prefer “flatter” flowers like clovers, thistles, goldenrods, and asters.  The BugLady doesn’t know where this one was hiking to – she saw several others on flowers in the area.  A little rusty on bumble bees?  Here’s a great bumble bee guide from the Xerces Society: https://www.xerces.org/publications/identification-monitoring-guides/bumble-bees-of-eastern-united-states

Go outside, look at bugs,Professor, Dr. Richard B. Fischer, the content of whose fantastic natural history courses she uses Every! Single! Day!  (right BugFan Mike?)  He would have enjoyed BOTW. 

Kate Redmond, The BugLady

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

Bug o’the Week – Gone Fishin’

Bug o’the Week
by Kate Redmond

Gone Fishin’

Greetings, BugFans,

Here’s a rare glimpse into the BugLady’s “BOTW Future” file, which is packed with pictures of identified insects that she hopes have a good story to tell, with semi-identified insects, and with (mostly) her “X-Files” – the Unidentified.  (The file probably reflects the state of the BugLady’s brain.)  It’s what she sees as she selects the bug of the week.

Traditionally, the BugLady goes on sabbatical for the month of June, but she’s going to sneak away a bit early this year.  Why?  There’s an old riddle,

“Why did the glaciers retreat?”

“To get more rocks.”

 

The BugLady needs more pictures.

Lest your inbox grow cobwebs, she will post a tasteful rerun each Tuesday until she gets back.

FROM THE FILE:

BEE X23 (on bergamot)23-1 – a busy little bald bee.

BEETLE MILKWEED ANNULATUS HL22-2 – Not our common Red milkweed beetle (Tetraopes tetropthalmus).  There are two species here that are adorned with those lovely double rings on the antennal segments – T. femoratus (which has red on its legs, unless it doesn’t), and T. annulatus, sometimes called the Ringed milkweed beetle.  The BugLady would happily call this T. annulatus based on appearance and habitat (dry, sandy areas), but it was sitting on Common milkweed, which is not listed as one of annulatus’s food plants.  Is the BugLady overthinking this?  Probably.

TULE BLUET DAMSELFLY21-2 – with a bunch of water mite nymphs on its abdomen.  The BugLady knows who this is, but she’s written biographies of a number of other bluets, and the details of their life histories don’t vary a lot.  Besides, she promised that she would not march methodically through the species lists of Wisconsin dragonflies and damselflies.

So many wasps!!!

BRACONID15-22 – someday the BugLady is going to write a Braconid Wasps 101 episode (they’re a big and important family) but first she needs to figure out which of her wasp pictures are braconids, because they can look similar to Ichneumon wasps (an even bigger family).  This one seems to be ovipositing in the flower.

WASP ICHNEUMON Latholestes17-10 – maybe a braconid.

X WASP17-1 – also maybe a braconid

WASP ICHNEUMON RNC22-1 – a large and handsome Ichneumon.

WASP MISTLETOE SLB24-3 – this Ichneumon (probably) was exploring the flowers of Eastern dwarf mistletoe.

WASP FBMP OOF24-2 – an odd little wasp that joined the BugLady on the Hawk Tower on a cool day in mid-November.

X MOTH20-7 – this handsome, largish moth looks like it should be in the genus Haploa but…..

FLY DEER RNC23-2 – looks like a deer fly, but cinnamon- colored?

PLANTHOPPER NYMPH13-1 – isn’t this a little cutie!

SPIDER WAUB24-1 – what a lovely, almost translucent spider!

X LONGHORNED BEETLE HL15-2 – enjoying the wild geranium one spring day.

WEEVIL EP12-1 – Isn’t this a great little weevil?  The BugLady scooped it from the surface of an ephemeral pond, but she doubt’s that it’s an aquatic species – more likely it was sitting on a leaf and got dislodged.

See you in July,

Kate Redmond, The BugLady

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

Bug o’the Week – The Clover Leaf Weevil and Other Tales

Bug o’the Weeku
by Kate Redmond

The Clover Leaf Weevil and Other Tales

Howdy, BugFans,

The BugLady has been playing outside, and she had trouble coming in long enough to write these stories.

STORY #1 – THE CLOVER LEAF WEEVIL.  The BugLady took a few “throw-away shots” of this little (3/8” long) beetle as it crawled along a boardwalk in a wetland, and she made a few inaccurate guesses about its identity, but the sun was bright and she couldn’t really see the image on the screen, and then she and the beetle went their separate ways.  Turned out to be a completely different beetle than she thought, one that apparently took a wrong turn at the start of the boardwalk.  

It was a weevil https://bugguide.net/node/view/859710/bgimage, a weevil that has gone through more than a dozen combinations and permutations of scientific names since it was first described in 1763 (“A rose by any other name….”) and that can still be found under multiple names in the contemporary literature.  Some of the names resulted when the species was described and named by one person, but had already been described and named by another (18th century entomologists received specimens from contacts all over the world, and communication among them was slow).  Other name changes happened when the family or subfamily or genus of the weevil was revised (and some of those changes were not embraced by others in the field).  The BugLady gets the feeling that the dust has not settled on this weevil’s name. 

The Clover, or Sandy, Leaf Weevil (we’ll go with Donus zoilus) is in the Snout/Bark beetle family Curculionidae.  It’s the only member of its genus in our area, but there are a lot more genus members globally, and it’s not from around here.  It was originally found in the “Palearctic realm” – Europe and Asia between the Arctic and North Africa/India.  With a little help from its friends (us), it jumped the Big Pond and came to live in the Nearctic realm (North America between the Arctic and Mexico).  It made its North American debut in Quebec in 1853, and now it’s present over about three-quarters of the country.  . 

Here are some glamour shots: https://bugguide.net/node/view/141240/bgimagehttps://bugguide.net/node/view/859709/bgimage

Its habitat is listed as grasslands, clearings, roadsides, and edges, and while adults may feed on a few plants that are not in the Pea family (the BugLady can recall no members of the Pea family along that boardwalk), the raison d’être for both adults and larvaeis eating agricultural clovers, especially alfalfa.  Larval host plants include alfalfa, red, white, crimson, and alsike clovers, and sweet clovers (sweet clovers (the Devil Incarnate), of which they may consume as much as they can hold). 

Both adult and larval Clover leaf weevils feed at night or on cloudy days, and shelter on/in the ground in the sunlight.  The larvae/grubs https://bugguide.net/node/view/1535920 make small holes in the leaves.  Most sources said that unless they occur in high numbers, they’re not a major crop pest (unlike the much smaller, Alfalfa leaf weevil).  The grubs are parasitized by the larvae of this lovely little ichneumon wasp https://bugguide.net/node/view/1152272.

There’s only one brood per year – females place eggs in and around the host plants in fall.  Most eggs hatch then and the larvae overwinter, feeding when it’s warm enough and resting when it’s not, then pupating https://bugguide.net/node/view/1535924 and becoming adults in spring.  Any eggs that overwinter hatch in spring.  Newly-emerged adults feed and then aestivate (suspend operations) for part of the summer, reactivating and laying eggs in fall https://bugguide.net/node/view/1655976/bgimage.  Larvae chew on plants in spring, and adults chew on plants in fall. 

STORY #2 – RECENT SPIDER ADVENTURE.  The BugLady headed to the laundromat the other day.  She got a few miles down the road and noticed (belatedly) a Cross Orbweaver on a strand of web on the inside of the driver’s side window (“along came a spider and sat down beside her…”).  She found an uninhabited side road and pulled way over to the left, so the side of the car was in grass, opened the window and nudged the spider out, hoping to move it away from the car.  When she got to the laundromat, the windblown spider was curled tight, clinging to the side of the car below the mirror.  It stayed there while the laundry went around, and then held on for the ride home.  The BugLady lifted her off with a leafy twig, and the spider recovered on the porch rail.  Spiders are tough! 

STORY #3 – AN EXUBERANCE OF DRAGONFLIES.  We experienced a wonderful, three-day dragonfly migration from August 30 into September 1, and in the run-up to that migration, the BugLady enjoyed some amazing walks through big feeding swarms, with darners cruising past, inches away.  As she went out to the hawk tower on Sunday, darners and saddlebags were in the air everywhere, with even more jumping up from the grass as she passed.  When she scanned for incoming hawks, the view through her binoculars was dragonflies as far out as she could see, in all directions.  Magic!  Abruptly, at 1:00 PM, the wind shifted a bit and it was over, and only the stragglers remained. 

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 12 (or 13) Bugs of Christmas

Bug o’the Week
by Kate Redmond

Bug o’the Week The 12 (or 13) Bugs of Christmas

Greetings of the Season, BugFans,

(13 bugs, because once she’s got her selection down to 13, the BugLady just can’t cut one more!)

A Cheery Thought for the Holidays, the average home contains between 32 and 211 species of arthropods (with the lower numbers at higher Latitudes and higher numbers as you head south past the Mason-Dixon Line).  So, while the BugLady is celebrating The 12 (or 13) Bugs of Christmas, most BugFans could rustle up at least that many under their own roofs.  Whether you see them or not, all kinds of invertebrates coexist with us daily, mostly staying under our radar until we surprise each other with a quick glimpse.

Here are a baker’s dozen of the bugs that the BugLady saw in 2023.

BALTIMORE CHECKERSPOT CATERPILLAR – According to one researcher, caterpillars are “essentially bags of macerated leaves.”  What kind of leaves does a Baltimore Checkerspot caterpillar macerate?  The eggs are laid in the second half of summer on, historically, White turtlehead, a native wildflower, and more recently, Lance-leaved plantain has been added as a host plant.  Both plants contain chemicals that make the caterpillars distasteful to birds, though the turtlehead has higher concentrations of them.  The butterflies have adapted to use an introduced plant, but the caterpillars don’t do as well on it (the BugLady has also seen them on goldenrod).  Half-grown caterpillars overwinter, and when they emerge to finish eating/maturing in spring, the turtlehead isn’t up yet, so they eat the leaves of White ash and a few spring wildflowers.   

LEAFCUTTER BEE ON PITCHER PLANT – Bumble bees and Honey bees are listed as the main pollinators of Purple pitcher plants, along with a flesh fly called the Pitcher plant fly (Fletcherimyia fletcheri), a pitcher plant specialist that contacts the pollen when it shelters in the flowers.  But it looks like this Leafcutter bee is having a go at it. 

SEVEN-SPOTTED LADYBUGS had a moment this year; for a while in early summer, they were the only ladybug/lady beetle that the BugLady saw.  Like the Asian multicolored lady beetle, they were introduced from Eurasia on purpose in the ‘70’s to eat aphids.  But (and the BugLady is getting tired of singing this chorus) they made themselves at home beyond the agricultural fields and set about out-competing our native species. 

An Aside: Lots of people buy sacks of ladybugs to use as pest control in their gardens.  The BugLady did a little poking around to see which species were being sold.  Some sites readily named a native species, but most did not specify.  Several sites warned that unless you are buying lab-grown beetles, your purchase is probably native beetles scooped up during hibernation, thus posing another threat to their numbers

SOLDIER FLY LARVA – The BugLady is familiar with Soldier fly larvae in the form of the flattened, spindle-shaped larvae https://bugguide.net/node/view/1800040/bgimage that float at the surface of still waters, breathing through a “tailpipe” and locomoting with languid undulations.  So she was pretty surprised when she saw this one trucking handily across a rock in a quiet bay along the edge of the Milwaukee River.  It appears to have been crawling through/living in the mud. 

COMMON WOOD NYMPH – And an out-of-focus Common Wood Nymph at that.  The BugLady has a long lens, and her arms weren’t quite long enough to get the butterfly far enough away to focus this shot.  And it’s really hard to change lenses with a butterfly sitting on your finger.

FALSE MILKWEED BUG – Milkweed bugs are seed bugs that live on milkweeds, but if you’ve ever seen a milkweed bug that was not on a milkweed (usually on an ox-eye sunflower), it was probably a False milkweed bug.  They’re so easily mistaken for a Small milkweed bug that one bugguide.net commentator said that all of their pictures of Small milkweed bugs should be reviewed.  Here’s a Small milkweed bug with a single black heart on its back bracketed by an almost-complete orange “X” https://bugguide.net/node/view/2279630/bgimage; and here’s the False milkweed bug, whose markings look (to the BugLady) like an almost complete “X” surrounding two, nesting black hearts https://bugguide.net/node/view/35141.  One thoughtful blogger pointed out that although it looks like a distasteful milkweed feeder, it’s not thought to be toxic.  He wondered if this is a case of mimicry, or if the bug once fed on milkweed, developed protective (aposematic) coloration, and then changed its diet?

LARGE EMPTY OAK APPLE GALL – That’s really its name, but “empty” refers to the less-than-solid interior of the gall https://bugguide.net/node/view/54459 (which was made by this tiny gall wasp https://bugguide.net/node/view/260612).  Galls are formed (generically) when a chemical introduced by the female bug that lays the egg, by the egg itself, and later by the larva, causes the plant to grow extra, sometimes bizarre, tissue at that spot.  The gall maker lives in/eats the inside of the gall until it emerges as an adult.  Some galls are made by mites – same principle.

SYRPHID FLIES are pretty hardy.  Some species appear on the pussy willows and dandelions of early spring, and others nectar on the last dandelions of late fall.  This one was photographed on November 17, on a sunny and breezy day with temperatures in the low 40’s, 12 feet off the ground, resting on the BugLady’s “go-bag” (the bag of extra clothes she carries up onto the hawk tower to deal with the wind chill).

WASP WITH SPIDER – The BugLady saw a little flurry of activity near an orbweaver web on her porch one day, but she got it backward.  At first she thought that the spider had snagged the wasp (a Common blue mud dauber), but it was the wasp that hopped up onto the railing with its prey, part of the spider collection she will put together for an eventual larva.

SIX-SPOTTED TIGER BEETLES grace these collections perhaps more than any other insect, because – why ever not!

JUST-EMERGED DAMSELFLY – This damselfly was so recently emerged (possibly from the shed skin nearby) that its wings are still longer than its abdomen (basic survival theory says that you put a rush on developing the parts you might need most).  Will a few of the aphids on the pondweed leaves be its first meal?

This is either a GREEN IMMIGRANT LEAF WEEVIL (Polydrosus formorus https://bugguide.net/node/view/1678834/bgimage) or the slightly smaller (and equally alien) PALE GREEN WEEVIL (Polydrosus impressifrons https://bugguide.net/node/view/1813505/bgimage).  Whichever it is, it’s been in North America for a little more than a century.  Bugguide.net calls them “adventive” – introduced but not well established.  Eggs are laid in bark crevices or in the soil, and the larvae feed on roots.  Adults eat young leaves, buds, and flowers of some hardwood, fruit, and landscape trees but are not considered big pests.  Their lime-green color comes from iridescent, green scales.

And a DOT-TAILED WHITEFACE in a pear tree.

Have a Wonder-full New Year,

Kate Redmond, The BugLady

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

Bug o’the Week – Southern Corn Billbug

Bug o’the Week
by Kate Redmond

Bug o’the Week Southern Corn Billbug

Greetings, BugFans,

As Seasoned BugFans know, the BugLady is a fan of weevils – she loves the cut of their tiny jibs (for “jibs” read “snouts”) (for “snouts” read “rostrums”).  Snouts tipped with chewing mouthparts and adorned with clubbed and elbowed antennae https://bugguide.net/node/view/1038921/bgimage, snouts long and slender https://bugguide.net/node/view/2308802/bgimage, and snouts short and stout https://bugguide.net/node/view/2003970/bgimagehttps://bugguide.net/node/view/1959459/bgpage.  So she was excited to find a Southern corn billbug while she was in a park on the Milwaukee River – an odd spot, but you’re never far from a corn field in Wisconsin.

Who are the billbugs?  They are members of the beetle order Coleoptera, the largest order in the whole animal kingdom with about 390,000 described species (the Coleoptera account for about 40% of all insect species), and of the beetle family Curculionidae (the bark and snout beetles), the largest family in the whole animal kingdom, with 50,000 species worldwide.  As British biologist J.B.S. Haldane (may have) said, the Creator had “an inordinate fondness for beetles.”  Billbugs, so-named for their curved snouts, are weevils in the genus Sphenophorus (from the Greek for “wedge-bearer”), with 65 species in North America and more elsewhere.

As a group, Billbugs are persona non grata because of the habit of many species, mainly in the larval stage, of feeding on members of the grass family.  Billbugs tend to be pedestrians – they’ve been observed in flight, but not very high and not for very long (and with a tailwind), and their larvae are legless, which means that they don’t disperse quickly.   

Despite their name, SOUTHERN CORN BILLBUGS(Sphenophorus callosus) are notably absent from much of the South https://bugguide.net/node/view/278604/data.  The North Carolina University Extension describes their range thus: “the Coastal Plain of the Carolinas and Georgia. However, this pest damages corn over the entire Coastal Plain of the southern states and up the Mississippi River valley into the Midwest.”  Their name doesn’t seem to set off any alarms with University Extension offices here in Wisconsin.

Southern corn billbugs are a little more than one-third of an inch long and are a little lumpy-looking.  Some are brownish in color https://bugguide.net/node/view/1933001/bgimage, and they often carry a coating of dust or dirt.  Here’s a glamour shot – https://bugguide.net/node/view/77598/bgimage.  

While many billbugs go for turfgrass and some attack rice, Southern corn billbugs specialize in corn (rice and corn are members of the grass family).  It’s a one-two punch – the larvae feed at the base of the plant, and the adults feed higher up, and the “jaws” at the ends of the adults’ snouts allow them to reach into the inner tissues of the stem.  Adults like several other plants, like sorghum (another grass), and they especially like Yellow nut sedge, aka Chufa, a maybe-native-maybe-not sedge that’s considered an invasive agricultural weed (click on any picture for a slide show https://www.minnesotawildflowers.info/grass-sedge-rush/yellow-nutsedge). 

Southern corn billbugs overwinter as adults in leaf litter or barely underground, often in ditches and hedgerows near corn fields.  They emerge as the young corn emerges and trek into the field (they also float well), and they’re more likely to be found in corn plants around the periphery of a field than the interior. 

Females lay eggs toward the base of the corn stem, in holes they made while feeding.  When the larvae hatch (just one per stem, but there may be as many as five in a stem if billbugs are thick on the ground), they move down the outside of the stem and feed in the roots and then bore into the lower stalk.  Needless to say, this makes it hard for the young plant to thrive.  They pupate in cells in the corn stalk or root, or in the soil.  Newly-minted adults may emerge to feed before tucking in for the winter, or they may hunker down until spring.    

Rotating crops keeps billbug numbers down, and farmers who practice continuous no-till agriculture have higher infestations.  One potential biological control is (Science Word of the Week) entomopathogenic nematodes.  Nematodes are small roundworms that are, according to Britannica, “among the most abundant animals on earth.”  Nematodes are – well – everywhere (https://uwm.edu/field-station/bug-of-the-week/nematodes-for-poets/).  Entomopathogenic (pronounced just like it looks) means that the nematodes are able to cause disease in the billbug larvae or other insects they encounter. 

According to the University of Florida’s Featured Creatures page on the topic, “Entomopathogenic nematodes occur naturally in soil environments and locate their host in response to carbon dioxide, vibration and other chemical cues.”  A nematode carrying symbiotic bacteria (bacteria that it lives peaceably with) enters the larva’s body cavity and bacteria are released there.  The bacteria multiply, the larva dies, and the nematode feeds, matures, and reproduces within. 

The BugLady can’t recall if she’s shared this dynamite article about the decline of insects.  Great graphics!  https://www.reuters.com/graphics/GLOBAL-ENVIRONMENT/INSECT-APOCALYPSE/egpbykdxjvq/

Kate Redmond, The BugLady

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

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