Category: Bug of the Week

Greetings, BugFans,

The BugLady’s favorite insect is the Tiger Swallowtail (Mom likes me best), but in the crowded field for second place, the Luna Moth is pretty close to the top.  

Luna moths (Actias luna) are in the Giant Silkworm/Royal Moth family Saturnidae (of previous BOTW fame https://uwm.edu/field-station/giant-silk-moths-family-saturnidae/), whose family members have ringed eyespots reminiscent of Saturn.  The LM’s name came from eyespots that resemble moons (eyespots that make predators ponder whether their target might be different than they originally thought).  Actias is a small genus with about two dozen species worldwide, and the LM is the only American species.  They are found in wooded areas east of the Great (on rare occasions, LMs have made their way to Europe).

And giant they are, with wingspreads that often exceed four inches.  Males and females look pretty much alike; her egg-laden abdomen is larger than his, and his antennae are fancier than hers.  Both have what’s called quadripectinate antennae, which means that they are comb-like, with four “tines” per unit of the antenna https://bugguide.net/node/view/754599/bgimage, https://bugguide.net/node/view/293789/bgimage, and the female https://bugguide.net/node/view/426762/bgimage.  Their long, twisted tails are said to interfere with bat radar, and they also present a false target for predators – bats manage to snag some LMs, but many others get away after the bat mistakenly grabs them by those spectacular tails.  

(LMs make photographers sweat (“please don’t let me screw up, please don’t let me screw up….).  Here are some photographers who didn’t screw up https://bugguide.net/node/view/20728/bgimage,https://bugguide.net/node/view/617459/bgimage, https://bugguide.net/node/view/655366/bgimage, https://bugguide.net/node/view/917529/bgimage, and (possibly posed) https://bugguide.net/node/view/1532344/bgimage).

Warming weather signals them to emerge from their cocoons, which they accomplish with the aid of an enzyme (named cocoonase!!) that they secrete to soften the dried silk and of a hard spur at the base of each front wing, which they use to break through it; here’s a video and of an LM eclosing (emerging) https://www.youtube.com/watch?v=FECzFIRPeD4, and some still shots https://bugguide.net/node/view/481690/bgimage.  Then they pump up their wings and begin their short lives as adults.  Females emit a pheromone that calls males to her perch.  His feathery antennae allow him to sense a mere handful of scent molecules from two or more miles away and to follow the increasingly concentrated scent trail to her.  Lunas are nocturnal, and most mating occurs after midnight.   

Adults have neither mouth nor gut, and they live only about a week, dying soon after they reproduce.  There is one brood per year here in God’s Country, and two or three in the south. 

Females lay between 200 and 400 eggs, singly and in clumps, on host plants.  LM caterpillars feed on the leaves of birch, hickory, walnut, maple, and sumac, and add sweet gum, pecan, and persimmon in the south (they aren’t considered forest pests).  They show regional favoritism – LMs in our area prefer birch and do badly if moved to a different food plant.  One theory is that LM caterpillars are capable of processing the defense chemicals produced by their host trees, and they may become specialists in detoxifying a particular species.  Young caterpillars https://bugguide.net/node/view/1434316/bgimage are knobbier than older ones https://bugguide.net/node/view/1191475/bgimage.  

Mature caterpillars become dark red before pupating; they drop to the ground and use silk to wrap themselves in a leaf for the winter https://bugguide.net/node/view/1191457/bgimage, camouflaged in the litter of the forest floor.  LM pupae are not passive – if they are disturbed, they will move noisily within their cocoon.  Jim Sogaard, writing in Moths and Caterpillars of the North Woods tells us that “The pupa has a clear ‘window’ through which even dim light can stimulate the brain.  Photoperiod likely contributes to breaking diapause [the suspended animation of winter].  If a cocoon is moved, the pupa within may noisily reorient itself to the light.”  Here’s a nice stage-by-stage series: https://bugguide.net/node/view/945719. 

A two inch long LM caterpillar looks like a feast for any predator that finds it despite its green camouflage, but the caterpillar has a bag of tricks that includes rearing up on its back legs, warning its would-be attacker by making clicking sounds with its mandibles, and then regurgitating the noxious contents of its intestine. 

LMs are not common, and they are becoming less so.  Their natural predators include bats, owls (one source told of a Screech Owl that fed on males that came to visit a female calling from a branch), spiders, and toads. 

Human activities also impact them: 

• A tachinid fly imported in 1906 to control gypsy moths now parasitizes the caterpillars of almost 200 species of native butterflies and moths, including the giant silk moths.

• Habitat loss due to urban street trees being cut and deciduous woods becoming more fragmented.  The caterpillars can’t adapt to non-native tree plantings.

• Pesticides that affect not only the leaves that the caterpillars eat, but also the immobile pupa, and even the short-lived adults.  

• Light pollution – LMs are strongly attracted to lights at night, exposing them to predators and, with the clock ticking loudly, distracting them from the task at hand.

Fun Luna Moth Fact – a bunch of butterflies have been featured on US postage stamps, but in 1987, the LM became the only moth (before or since) to be so honored.

Just in case you still haven’t seen enough LM images, https://www.marylandbiodiversity.com/viewSpecies.php?species=345. 

Look for them in the month of June. 

To paraphrase the Bard, “O brave new world, that has such creatures in’t!”

Kate Redmond, The BugLady

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

Salutations, BugFans,

Life is busy, and besides, May is National Wetland Month, so here’s a rerun from ten years ago.  A few new words and pictures. 

The BugLady will visit these guys together because even though they are, in a sense, photo-negatives of each other, they are often mistaken for one another (until you know the secret handshake). The majority of aquatic animals, from orcas to Mergansers to muskies to water boatmen tend to be dorsally dark and ventrally light (have dark backs and light bellies).  This coloring is protective because a predator looking down from above has to distinguish its dark-backed prey from the dark water surface, and a predator looking up from below sees a light belly against a surface that reflects the light of the sky.  The backswimmer, which spends its life rowing around belly-up, flip-flops the usual color scheme and has a dark belly and a light back. 

These two aquatic, boat-shaped, less-than-a-half-inch-long, “True Bugs” (Order Hemiptera) are not in the same family, and the water boatman also departs from the usual mouthparts and diet of its compatriots, but they have many similarities.  They are found in still waters – preferably with aquatic plants – including ponds, lake edges, sewerage ponds, bird baths, and even swimming pools (lots of websites devoted to getting rid of water boatmen and backswimmers in swimming pools), and they are more active in the dark than in the light.  They locomote via rowing movements of their flattened third pair of legs (backswimmers) or second and third pair of legs (water boatmen) and are often seen swimming or grabbing plant stems in a head-down position. They are strong fliers, although the up-side-down backswimmer must climb out of the water and flip over onto its belly before it can spread its wings and take off.

Both bring a tank of oxygen with them as they swim underwater.  The backswimmer stores air in two hair-covered troughs on the ventral side of its abdomen (it can stay underwater for as long as six hours), and the water boatman wraps a bubble of air under its wings and around its abdomen and also picks up dissolved oxygen from the water (it is so buoyant that it must grab vegetation in order to keep from floating to the surface).  Both overwinter as adults, and some water boatmen may remain active under the ice.  The males of both groups stridulate – rub rough area on their front legs against their head – “chirping” underwater to attract mates. 

Backswimmers (family Notonectidae) are piercer-predators that kill and suck the bodily fluids out of any prey they can subdue – invertebrate and vertebrate alike – including tiny tadpoles and fish fry (but big fish eat backswimmers).  Each set of legs is used for a different function – the front pair for catching their prey, the middle pair for holding the prey tight, and the flattened, hairy third pair acts as oars.

These little “Davids” will sometimes go after Goliath, piercing the leg of a human swimmer or wader, a habit that has earned them the name of “water bee” or “water wasp.”  It is a painful, burning bite that can have lasting effects in those who may be “susceptible to poisons,” according to Anne Haven Morgan in the Field Book of Ponds and Streams.

The often red-eyed Water boatmen (Family Corixidae) are a bit smaller than backswimmers.  Collector-gatherers, they swim along the bottom of the pond, head down, in search of food, and they use their front pair of legs to scoop it up.  Lacking the standard piercing beak issued to other aquatic true bugs, they ingest living material – diatoms, algae, protozoa, nematodes, small insects – that they find when they stir up debris on the bottom of a body of water. Some suck juices from algae. 

The eggs and the adults of water boatmen are eaten by birds and by humans (an Egyptian and a Mexican delicacy, according to some references) and were said to have been introduced to England as a food source.  The Handy Bug Answer Book by Dr. Gilbert Waldbauer recounts how bundles of rushes that are put into ponds in Mexico as a substrate for water boatmen to lay their eggs upon are removed, dried, and beaten to loosen the eggs.  The eggs are then cleaned and ground into flour to make a cake called “hautle.”

Besides their surprising edibility and the fact that they are said to smell like bedbugs, the water boatman’s only other claim to fame is that the males of some species make ultrasonic mating calls with what Monty Python would call their “Naughty-bits.”  Do not try this at home.

Kate Redmond, The BugLady

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

Greetings, BugFans,

The poet Muriel Rukeyser once wrote, “The universe is made of stories, not of atoms.”  The BugLady sees lots of tableaux unfolding as she ambles across the landscape (most have to do with food or sex).  Because she was taught, at an impressionable age, by a professor who said “Don’t just tell them what it is, tell them ‘what about it,’” she tries to read the stories and understand the “what-about-its”. 

The SPIDER and the FLY – and the AMBUSH BUG

Heterospecific (belonging to different species) predators mostly don’t share, and both the spider and the ambush bug would consider this fly to be a toothsome morsel.  The BugLady figures that the ambush bug caught it, and the slender crab spider (Tibellus sp) saw the struggle and popped over to investigate, but not to appropriate it.

BUCKTHORN

Glossy buckthorn is a Eurasian shrub that was brought over in the late 1800’s to be a lawn/hedge shrub, but because it is a “bird poop seed,” it didn’t stay domesticated.  It is a huge problem in wetlands (well, actually, it likes wet, dry, sunny and shady soils) and like other invasive plants, it left its natural grazers behind in the Old Country.  The BugLady found this sawfly larva eating buckthorn leaves (she had previously photographed a lightning beetle apparently feeding on nectar or pollen from a buckthorn flower), thus demonstrating the Reinartz Law of Biomass Availability, aka “If you grow it, they will come.”  More scientifically put, glossy buckthorn (and other invasive plants) represent a huge biomass of potential food, and eventually herbivores will figure out that they’re edible.  Sooner, we hope, rather than later. 

DOR IN OHIO –

Why did the Japanese beetle cross the road?  The story that the BugLady reads here was initiated by the picture’s shiny green centerpiece, a Japanese beetle that did not survive the crossing.  It proved attractive in death to two opportunistic scavengers, a millipede and a daddy long-legs (that better keep their wits about them or they might not get across, either).  The daddy long-legs’ legs are decorated by nymphs of red mites, which go through a tick-like, parasitic phase before they grow up to eat insect eggs and very small invertebrates. 

GYPSY MOTH ON BEECH

This picture shows three out of four life stages occurring within inches of each other.  Gypsy moth larvae get around pretty well – newly-hatched caterpillars use silk to balloon to new locations, and if they and their confreresdefoliate the tree they land on, they’ll take off on foot to find another!  Adult females are a different story.  They emerge from their pupal case flightless, use pheromones to lure flying males to their tree trunk perch, and then create an egg case on the same spot.  Not surprisingly, the BugLady is not a rabid advocate of gypsy-moth-control: https://uwm.edu/field-station/gypsy-moth/.

EGG-GUARDING SPIDER

The BugLady photographed this female Philodromid (running crab) spider over a period of four days, guarding the eggs that she had placed inside an empty beech nut (did that nut shell land randomly on the leaf and stay there, or could a spider haul it up to the leaf’s surface?).  Egg guarding is common among philodromids, and she hung tough, day after day, as the BugLady and her one-eyed camera loomed above her (the BugLady appreciates cooperative subjects, and she thanks them, but she worries about their survival instincts).  On the fifth day, the spider was gone, and the ending of this story is a mystery. 

CRAB SPIDER AND RIPIPHORUS

What’s a collection of pictures without a crab spider, in this case a lovely northern crab spider (Mecaphesa asperata), sitting on a Grass of Parnassus flower, preying on a Ripiphorus beetle (and illustrating, once again, that when it comes to camouflage, crab spiders got it right)?  Ripiphorus/ Rhipiphorus beetles (the genus seems to be spelled both ways) are fly mimics, but the BugLady still doesn’t see the advantage of looking like a fly when you could look like a beetle.  For the scoop on Ripiphorus, see https://uwm.edu/field-station/its-a-beetle-really/.    

MULLEIN TABLEUX

Mullein was deliberately introduced to North America in the 1600’s because the newly-arrived settlers loved it and had many uses for it back home (six species in this collection, including, of course, the European Americans themselves, are “non-native”).  Mullein seed weevils were introduced for the purpose of eating mullein seeds, which they do with about 50% efficiency (https://uwm.edu/field-station/mullein-watching/).  The BugLady was thinking, as she photographed the weevils, that (speaking of crab spiders) their trip to the honeymoon suite might not turn out as planned. 

EXUVIA 

And finally, spring is a time of rebirth, renewal, and resurrection.  What better symbol of that spirit than the empty shell (exuvia) of a baskettail dragonfly naiad that emerged from a winter spent in the watery world below the ice, climbed up (in this case) the stalk of a horsetail/equisetum, broke out of its old skin, and cast its die as a creature of the air? 

Kate Redmond, The BugLady

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

Greetings, BugFans,

The BugLady always enjoys photographing these large, handsome grasshoppers as they ricochet off the prairie plants in late summer.  She has danced around them in several episodes – in a generalized discussion of their genus, Melanoplus https://uwm.edu/field-station/melanoplus-grasshoppers-redux, and as eye-candy in several summer insect picture collections – but they deserve their own biography. 

The Two-striped/Yellow-striped Grasshopper/Locust (Melanoplus bivittatus) is in the short-horned grasshopper family Acrididae.  Besides having a few interchangeable common names, it has gone through about a dozen combinations of five genera and a half-dozen species names in the past two hundred years. 

If you’re in North America, there’s probably a TSG near you (except for Florida, the Gulf and south Atlantic coasts, the arid southwest, and northern Canada/Alaska).  Even with those cut-outs, that’s a lot of territory.  Bugguide.net describes their habitat as, “Varies with region, but usually relatively sunny, moist, lush, weedy or meadowy areas. Meadows, prairies, crop fields, road sides, vacant lots, ditch and stream sides … etc.”  And urban flower and vegetable gardens.  Again – a lot of ground.

Ditto, their menu.  The books label them as “polyphagous” (meaning, they eat many plant species).  They mainly enjoy leaves of herbaceous plants including grasses, but they’ll also tuck into woody plants, flowers and seed pods.  Their diet includes agricultural crops and garden plants, and they are unwelcome on the Great Plains, where their numbers sometimes reach “Biblical” (more about that in a sec).  According to a University of Wyoming publication, “A population of 10 adults per square yard in a corn field will defoliate the crop.”  And, more alarming, “Experiments indicate that in feeding on spring wheat the twostriped grasshopper wastes six times as much foliage as it eats.” 

Some plants produce chemicals that deter insect foragers, but the TSG is oblivious.  They also scavenge on dead plants and animals that they find on the ground and will resort to cannibalism when food is scarce. 

They do have some dietary requirements – they must ingest linoleic or some other fatty acid in their diet in order to keep their wings rigid.  And although they feed on many plants, there are particular species – certain mustards, broad-leaved plantain, red clover and alfalfa, dandelion, chicory, giant ragweed, and a few more – that allow young grasshoppers to grow faster and heavier. 

And these are big grasshoppers – females measure up to 2 ¼” and males to 1 ¼.”  Adults have a brown to yellowish-green body with a pale stripe on each side that starts at the eye and runs along the top of the body to the wingtips.  They have hearing organs on the abdomen, and although one source says that they buzz by rubbing their hind wings against their forewings, another says that they are believed to be silent, though the males produce vibrations.  Males are better fliers than females. 

A source that the BugLady finds frequently in her research is a blog called “The Backyard Arthropod Project – A Field Guide to the North Side of Old Mill Hill, Atlantic Mine, MI” (http://somethingscrawlinginmyhair.com/).  What’s not to like about a guy who says about his blog that, “As of February 2007, it has … turned into a project to document every arthropod that I can find on our property?”  The BugLady wishes him a wonderful journey. 

He suggests that because of their size and abundance, TSGs might be “one of the kinds that are numerous enough to collect for food. I’ve seen a couple of amusing methods suggested for catching large numbers of grasshoppers like this one. One is for two people to take opposite ends of a big, wooly blanket and run through a field with it, then pick off the hoppers that get caught in the wool. Another is to find a big field, dig a pit about 4 feet deep in it, then have a bunch of people start at the edges of the field and spiral in towards the pit. This drives the hoppers in, until you end up with a pit filled with grasshoppers that you just kind of shovel into bags. Then it’s just a question of pulling off the long hind legs (which can get caught in your throat because of the spines), and preparing using your favorite recipe.”  See https://uwm.edu/field-station/entomophagy/ for a BOTW episode called “Entomophagy 101.” 

TSGs take reproduction pretty seriously.  There’s not much by way of courtship – a male points his antennae toward his intended (preferably a virgin, but he will also pursue a female that has recently oviposited), sneaks up on her from behind, shakes his hind legs in a species-specific way, and takes a“copulatory leap.”  She may be agreeable, or she may depart, kick him, or curl up, but if a bond is established, they typically copulate for eight to ten hours.  A lot goes on during that time. 

Yes, he passes on a series of spermatophores (sperm bundles), thus ensuring the perpetuation of his lineage.  But there are proteins incorporated into his spermatophores – “nuptial gifts” that increase her fitness (she may also break down and absorb some of his sperm, for their nutrient value).  This, of course, is energetically expensive for the male, and he is not profligate.  The long duration of mating also guards her from rival males as she is processing his sperm.  A female can receive enough sperm from one liaison to last her whole life. 

OK – the BugLady is feeling a little like Dr. Ruth, here.

A week or two later, she lays up to 450 eggs in pods in the soil, or in debris on the ground, or in the middle of a hard-packed dirt road, as the female in the picture chose to do, and they overwinter as eggs, hatching in spring when the earth warms.  Eggs laid in mid-summer fare better than those laid later on, because the embryos have gotten further along in their development before cold weather shuts them down.  In agricultural areas, eggs are laid in hedgerows and along roadsides surrounding cultivated fields, and the nymphs move into the fields after hatching.  

These are not sedentary grasshoppers, and they have boom years in the Great Plains when favorable weather over a few years results in lots of food plants and a gradual population buildup.  TSGs respond to the crowding by producing a generation whose appearance and behavior are changed; migratory TSGs have longer wings and lighter bodies, and are gregarious, rather than loners.  If they feel crowded, even as young nymphs, they will migrate; in the heat of the day, adults fly (far) downwind at altitudes of 600 to 1,400 feet. 

Oh yes – The Grasshoppers of Nebraska tells us that “Unlike many other grasshopper species, it is quick to bite if handled.”

A grasshopper to be reckoned with! 

Kate Redmond, The BugLady

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

Salutations, BugFans,   

Leaves are coming.   Promise!   And soon after they emerge, we’ll see leaves that are folded, rolled, or otherwise harnessed by a variety of insects, for a variety of reasons.  The architects are mostly Lepidopterans – mostly small moths in the family Tortricidae – but there are also some skipper butterflies, beetles, sawflies, and spiders in the bunch, plus this cute little Carolina leaf roller cricket (https://bugguide.net/node/view/1473670/bgimage,https://bugguide.net/node/view/212744/bgimage), which shelters by day and hunts aphids by night (yes – a surprising number of grasshoppers and crickets eat animal matter). 

They’re grouped by “technique” – leaf rollers, leaf folders, and leaf tiers/webbers/“ugly nest makers.”  They use these structures to hide from predators or from the elements, to feed (some stay indoors and eat/skeletonize their “walls,” but others emerge to feed on nearby leaves and buds), to create a particular microclimate, to shelter their eggs (there’s a weevil that packages its egg in a rolled leaf, and the larva feeds within until it pupates), to pupate (after reinforcing the leaf stem with silk, a Promethea caterpillar wraps itself in a leaf and soon looks like dead vegetation hanging from a tree), or for any combination of the above.  Some male Jumping spiders make shelters for their future brides.  Many rollers/folders/tiers make predictably-shaped shelters on predictable hosts, but others are generalists.  

Leaf rollers take one leaf and form it into a tube or cone.  They may roll it the long way, parallel to the leaf’s midrib, or they may roll it crosswise, which has a higher degree of difficulty because they have to bend the midrib. 

Leaf folders, a.k.a. leaf sewers, fold rather than twist the leaves.  Most only fold it once, but some make several folds. 

Leaf tiers typically fasten together multiple leaves and may even enclose flowers or fruits.  They usually do their work at the tips of branches or twigs, making creations that are often labeled “unkempt.”  This category includes “ugly nest” caterpillars that bind a handful of leaves, and webworms, which lay clusters of eggs that hatch into clusters of caterpillars that throw silk around a whole branch and feed communally within, depositing frass and shed skins as they grow.

How do they do it?  In increments, using silk that contracts as it dries.  S. W. Frost, in the wonderful Insect Life and Insect Natural History (1942) (which considers insects by function, not by form) explains: If the roll is to be lengthwise, the strands of silk are spun perpendicular to the midrib of the leaf; if the roll is to be crosswise, the strands of silk are spun parallel to it.  As the strands dry, they shrink and pull the edges of the leaf inward.  New and shorter strands are then spun which in turn shrink and pull the edges of the leaf closer together.  This is continued until the edge of the leaf is drawn completely over and is fastened with other strands of silk…… Leaf folders bend the leaf at the midrib or along one of the principal lateral veins.  The silk is always spun on the upper side of the leaf, and the leaf naturally bends more easily in this direction.”  With persistence, a pretty small caterpillar can mold a pretty large leaf. 

You don’t have to be its architect to live in a shelter.  The adapted leaf persists after its original inhabitant is gone, and there are plenty of insects lined up to move in.  They may not even wait for it to be abandoned before they move in or oviposit into it (these “housemates” are called inquilines).  Says Richard Headstrom, in Adventures with Insects, “An interesting sidelight in connection with the habits of leaf-rolling insects is that when they abandon their shelters, other insects often take occupancy, and certain scavengers, particularly small mites and small beetles, feed upon the fecula [what a classy word!] left by the original makers.” 

In a Brazilian study, rolled leaves on a single plant species attracted five to nine times the number of species (depending on wet or dry season) as flat leaves.  According to researcher Camila Viera, “During the dry season, the rolled leaves on 60 plants in the Brazilian forest played host to more than 3,000 bugs alone, including spiders, beetles, whiteflies, crickets and many, many caterpillars….  The entire arthropod community hosted on Croton floribundus plants are influenced by leaf-rolling caterpillars.”  They are “ecosystem engineers.”

Abandoning a leaf structure is risky business, whether its maker is done with it, or has outgrown it and must make another, or the host plant is overcrowded, or an interloper has preempted a newly-formed shelter, or the nutrients inside the shelter are used up.  Mortality is high for caterpillars that suddenly strike out cross-country. 

One more (very cool) thing.  St. Johns-wort is a popular herbal remedy sold in health food stores as an antidepressant.  One problem with St. Johns-wort is that its leaves contain a chemical that we don’t completely metabolize, and it causes susceptible people to become photosensitive.  Turns out that some caterpillars are also affected when they feed on the leaves in sunlight – the chemical prolongs their larval stage and lowers their survival rate.  The solution?  They tie the leaves together and feed inside, in the shade. 

Kate Redmond, The BugLady

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

Salutations, BugFans,

They’re big, they’re beautiful, and they’re back! 

The BugLady has been out on the trail and has been enjoying the first butterflies and dragonflies of the season.  She walked the floating boardwalk at Horicon Marsh the other day – Common Green Darners everywhere!  Makes a person dream that spring might happen! 

Anyway, this episode started out nine years ago as “Spring Dragonflies,” continued six years later as “Three Spring Dragonflies plus One,” and reappears today as “Three Spring Dragonflies plus Two.”  If you check the BOTW archives, you’ll see that almost all of these species have starred in their own BOTWs.  

A genuine, though tentative, sign of spring is the reappearance of COMMON GREEN DARNERS, but the first sightings are usually not home-grown individuals.  COMMON GREEN DARNERS(family Aeshnidae) (whose scientific name, Anax junius, means “Lord of June”) arrive, often when the snow still lies in sheltered spots, as the insects they prey on take to the air. 

The Green Darners that deliver the spring soon lay eggs that hatch into aquatic naiads that take the whole summer to mature.  When these offspring make the trip south in fall, their flights along the Lake Michigan shoreline can be inspirational, and it is their offspring that repopulate the North Country with the spring.

In addition to its spring migrants, Wisconsin has non-migratory, resident population of Common Green Darners that emerge at about the time that the migrants have finished breeding and are completing their life cycles.  Natives replace migrants in our skies, and their naiads overwinter in frigid water under the ice. 

Common Green Darners are big insects, with bodies exceeding three inches and wingspans of four-plus inches.  Both sexes have a green thorax, but the male’s abdomen is blue and the female’s is brownish.  They have wrap-around compound eyes and a characteristic bulls-eye-like spot in front of their eyes. 

The warming of the water in spring is a powerful and irrevocable trigger.  Water changes temperature slowly – a lot of energy is needed to move it just a few degrees in either direction.  The next dragonflies on the scene signal that the water has warmed.  Their naiads crawl out of the water and out of their nymphal skins, pump up their wings and become creatures of the air, chasing their prey – flashes of wings that the dragonflies spot from perches or while in flight. 

COMMON BASKETTAILS (Epitheca cynosura) are drab dragonflies in the Emerald Family (Corduliidae).  They sport a black spot at the base of each hind wing, muted orange bars on a black abdomen, and short, gray hairs on their thorax.  As Cynthia Berger explains in her book Dragonflies, “like real fur, the fuzz helps hold in the heat generated by those muscle contractions [contractions of the flight muscles, which raise the temperature within the thorax].  Like darners, they perch vertically rather than horizontally, often hanging down from a twig tip.  Baskettails are agile flyers that may be seen in the afternoon hunting in groups above swarms of smaller insects like midges. 

“Baskettail” refers to the “basket” of eggs a female will carry under her abdomen.  According to bugguide.net, the genus name Epitheca is derived from epi (above) and theca (pouch or basket); a female carts her eggs around, sometimes all day, abdomen elevated, looking for the right spot to deposit them.  She may attach her ball of eggs to a submerged plant and then depart, or she may drag/tap her abdomen along the water’s surface, unraveling her string of eggs as she goes.  In either case, the once-compact egg mass swells into a strand an inch wide and six inches to several feet long (just add water). 

CHALK-FRONTED CORPORALS (Ladonia julia), in the Skimmer family Libellulidae, are northern dragonflies that often emerge in early May.  Adult males have white “corporal’s stripes” on the first segment of their thorax and white on the first few abdominal segments.  It’s called pruinosity, and it’s caused by an opaque, generally white/blueish-white, waxy substance that develops on the cuticle that covers the dragonfly’s exoskeleton (usually the abdomen, but sometimes other body parts) and gives it a powdered or hoary appearance.  Pruinosity is not only a sign of aging, it’s an indicator of breeding readiness.  Female Corporals are rusty brown with traces of white markings at the thorax and abdomen, and juveniles are a pinkish-brown with thin “shoulder” stripes and a black line down the center of the abdomen. 

Adult Corporals grab flying insects from royal ant/mosquito-size through small dragonfly-size.  They often perch on, bask on, and even hunt from the ground or a rock, and on cool days, hundreds may congregate on warm road surfaces.  They are known to follow people and pick off circling mosquitoes and deer flies.  Much has been written in these pages about the benefits of aposematic (warning) coloration and about the up-side of a prey species mimicking an aposematically-colored insect, but the Corporal appears to have read none of it.  In studies of food preferences, Chalk-fronted Corporals chose their prey by size – small prey over large – but they didn’t seem to care if it was wasp-colored or not. 

Darners and Baskettails and Corporals – Oh My!

And then there are Whitefaces. 

It would be hard to conjure up a more logical name for the DOT-TAILED WHITEFACE (Leucorrhinia intacta, family Libellulidae).  Both males and females have the “dot-tail” and the “white face,” though females tend to have a few yellow splotches along the top of the abdomen, and juveniles have, temporarily, even more.  Like some of the other early dragonflies, whitefaces have a pretty hairy thorax.

Dot-tailed whitefaces enjoy most kinds of quiet waters – bogs, marshes, swamps, sloughs, farm ponds, and even very slow streams – as long as there are low aquatic plants to perch on.  They bask on floating water lily leaves and on the ground, and they don’t gain much altitude when they fly.  The BugLady frequently sees them in her grassy field, some distance from water.  They emerge by late spring and fly through a good chunk of the summer into early fall. 

The DUSKY CLUBTAIL (Phanogomphus spicatus) is an early clubtail; look for it from late spring through mid-summer in Wisconsin.  The description of Dusky Clubtail behavior in Mead’s lovely Dragonflies of the North Woodsfits perfectly, “When not actively engaged in oviposition, Duskies are likely found far from water, perched in the sunshine on gravel roads, trails or rocks.” 

Many CLUBTAIL species (family Gomphidae) (but not all) are adorned with three noticeably-flared segments at the end of their abdomen that give them their name (a few non-Gomphids sport clubs, too).  The “club-less” clubtails are medium-sized, about 2 to 2 ½ inches long, with unspotted wings and striped bodies, and (usually) green, blue or gray eyes, and they have a short flight period during the first half of the dragonfly season.  They generally rest, hunt and fly close to the ground.  The stocky, young Gomphid naiads tend to burrow shallowly into the substrate, lurking with only their eyes exposed (to spot prey) and the tip of their abdomen (for breathing). Naiads may only crawl part way out of the water before they emerge.   

And then there are Common Whitetails…..

Darners and Baskettails and Corporals and Whitefaces and Clubtails (and Whitetails) – OH MY!

The BugLady

Howdy, BugFans,

There are a number of wildflowers that the BugLady stores in her mental “Texas Wildflowers” file because even though they occur elsewhere, she first saw/photographed them in Texas.  So, when she photographed this Gray Hairstreak in New Jersey, she put it in her “Butterflies of the East” file, but it doesn’t really belong there.  Gray Hairstreaks are, in fact, the most widely distributed American hairstreak, and they spill over into Canada, Central America, and the northern edge of South America.

That being said, there are plenty of places, especially in the northern half of that huge geography, where they are present but not common, or are present some years and not others.  They’ve been seen in more than half of Wisconsin counties but are rated as “uncommon” at the excellent Wisconsin Butterflies website https://wisconsinbutterflies.org/butterfly).

Why “hairstreak?”  These small butterflies in the family Lycaenidae and the subfamily Theclinae have one or two slim (hair-like) tails on the lower “corner” of each hindwing.  Some species also have Technicolor, false eyespots near the base of each tail.

What’s the point?  Many Lepidopterans have spots on the upper surface of their wings, spots that look like big, owl eyes that startle predators as the butterfly/moth flies away.  A hairstreak’s trickery happens when it’s perched, with wings folded.  Its eyespots and antenna-like tails are designed to fool predators into thinking that the butterfly’s head is where its tail is.  Hairstreaks even add a behavioral component – a nectaring hairstreak often moves its hindwings up and down, simulating the movement of twitchy antennae.  A butterfly that loses a chunk of its hindwing can survive (https://bugguide.net/node/view/52241), but a butterfly that loses its head – not so much.

Researcher Dr. Andrei Sourakov at the University of Florida suggested that while birds (and maybe lizards) are fooled by this display, it also provides a good defense against jumping spiders – sharp-eyed ambush hunters that ply the flower tops.  Jumping spiders, which usually grab the front end of a butterfly and inject venom into the thorax, attack the hairstreak’s false head and find no torso beneath to inject.

Gray Hairstreaks (Strymon melinus) (melinos means “ashen”) are not fussy about where they live – they’re happy in open spaces, parks, road edges, grasslands, gardens, and weedy, disturbed areas, often quite dry; they’re not fussy about food, either (BugFan Tom just passed along the wonderful term “catholic victulators”).  This flexibility in diet and habitat explains their wide distribution.  Adults nectar on a variety of plants with short, tubular flowers, like composites; and the caterpillar food list includes almost 200 species in about 20 plant families, especially peas, clover, cotton, hops, and mallows.  They are what the Butterflies of Massachusetts website (https://www.butterfliesofmassachusetts.net/) calls “Switchers” – butterflies that broadened their palettes when the European settlers brought Old World crops to the New World.  Young larvae feed in/on flower buds and developing fruits; older larvae may feed on leaves, and they have sometimes been a problem for bean and cotton growers (in cotton country, the caterpillars are called “cotton square borers”).

These lovely butterflies are small, with wingspreads of around 1 ¼”.  Males and females are similar, but females’ forewings are wider and rounder.  Their upper wings are gray-blue https://bugguide.net/node/view/1091008/bgimage), and they perch with their wings spread more often than other hairstreaks do.  Here’s a glamour shot https://bugguide.net/node/view/948914/bgimage, and a Gray Hairstreak gallery https://www.marylandbiodiversity.com/viewSpecies.php?species=529.

Males are territorial and feisty, spending their afternoons perching on vegetation, checking out any intruders, and watching for willing females. The Animal Diversity website says that “Mating pairs are normally spotted at night, and females oviposit during the midafternoon.”  Females lay eggs singly (rather than in clusters) on the flowers, flower buds, young fruits and nearby leaves of a host plant.  The caterpillars are greenish at the start, but older individuals range in color from gray to pink https://bugguide.net/node/view/225961/bgimage, https://bugguide.net/node/view/1320020/bgimage.  Here’s a nice life cycle series: https://bugguide.net/node/view/1134476.

Quick Science-y detour: Gray Hairstreak larvae are myrmecophiles (ant-lovers) – often tended by ants https://bugguide.net/node/view/59955 – an arrangement that is not uncommon in the Lycaenidae.  Ants harvest a sweet liquid from the caterpillar’s dorsal nectary organ (“honey gland”) and in exchange may protect them from predators (one source says that when searching for the well-camouflaged Gray Hairstreak caterpillars, it’s easier to look for the attendant ants instead).  The honey gland is located on the caterpillar’s seventh abdominal segment, and there’s a “tentacle organ” on the eighth segment that emits a chemical that gets the ants all riled up and defensive because it’s similar to an ant alarm pheromone. Larvae of many Lycaenid species also communicate with ants via ant-like sounds (clicks and hums) or by sending vibrations through the substrate; tropical biologist Philip DeVries calls them “singing caterpillars.”  An alternate explanation for this communication and honey sharing is that it deters the ants from preying on the caterpillars.

The Gray Hairstreak pupa also makes noise.

There are two broods in Wisconsin, starting late April/early May, and four, spanning most of the year, in the south.  Say Douglas and Douglas in Butterflies of the Great Lakes Region (2005), “Individuals from the spring brood are on the average smaller and darker than those from the summer brood.”  Those darker, smaller individuals may absorb heat better during the cool, early months of their flight.  The final generation of the year overwinters in a sheltered spot in the chrysalis stage.

But not in Wisconsin (at least historically), because it is unlikely that a Gray Hairstreak chrysalis could survive the polar vortex.  About Iowa, tropical enough to produce three broods each year, Schlicht, Downey, and Nekols (Butterflies of Iowa, 2007) tell us “Given the dearth of collections before mid-June, it seems likely that this species simply cannot overwinter in Iowa”.  So, where does that first generation come from?  Some sources say definitively that the Gray Hairstreak is not migratory.  Period.  Others say that the early individuals we see in the northern part of their range have flown in from the south to establish small colonies, except in the years when they don’t.  Douglas and Douglas again – It is likely that this species is highly vagile – capable of migration throughout its range.”

A Butterflies of Massachusetts analysis shows that Gray Hairstreaks are appearing earlier in spring today than they were 150 years ago and concludes that climate change will probably not be a problem for it.

Meanwhile, we need a much better name for this exquisite butterfly.  “Gray hairstreak,” while literally descriptive, just doesn’t do it justice.

Kate Redmond, The BugLady

Salutations, BugFans,

The DARK FISHING SPIDER is one BugLady’s favorite spiders (even though it isn’t even a crab spider).  First of all, it’s beautiful.  Second, it’s big, one of the biggest in North America – the leg-span of a large female can approach four inches!  Third, it’s a challenge to sneak up on and photograph.  The Hail Mary shot of the spider that’s snugged up under a wooden railing, in which the BugLady could see the front of her camera but not the back – a selfie of sorts – shows its typical attitude when company calls.

It’s in the Nursery web spider family Pisauridae, and we have visited the family in the form of the elegant Six-spotted fishing spider (https://uwm.edu/field-station/6-spotted-fishing-spider/) and in the form of the nursery web spider Pisaurina mira (https://uwm.edu/field-station/nursery-web-spider/).  Dolomedes is Greek for “wily” or “crafty,” and tenebrosus is from the Latin for “dark/gloomy/absence of light.”

They inhabit half of the continent, from the Dakotas to Texas to the Atlantic, and up into southeastern Canada.  Within that range they are often found near water, but they also stray far from it, commonly living on trees in woodlands and sometimes gaining access to basements (they may bite if handled – you might, too – but they aren’t aggressive).  They are mostly nocturnal hunters, sitting quietly on a vertical surface by day.

Females, with a body length of up to an inch, are about twice the size of males.  Their bodies range from pale https://bugguide.net/node/view/1367817/bgimage to dark, and from brown https://bugguide.net/node/view/1317001/bgimage to gray https://bugguide.net/node/view/1310830/bgimage (plus the odd, orange juvenile https://bugguide.net/node/view/805420/bgimage), and they have both black and light-colored markings.  Their legs are banded, and their eight eyes are arranged in two curved rows (the BugLady has never met a Dark fishing spider that was quite this cooperative: https://bugguide.net/node/view/1496981/bgimage).

With a name like “fishing spider,” it’s not surprising that their list of prey includes tadpoles, small fish, and aquatic insects.  These they find via vibrations produced when the prey traverses the surface film.  The spiders can skate, row, or run across the water (their legs are waxy); they can also dive below the surface to catch their supper, and an alarmed fishing spider may hide below the surface, too, for up to half an hour, breathing air that’s caught in its hairs.  Woodland dwelling fishing spiders feed on invertebrates (even slugs).  Larry Weber, in Spiders of the North Woods, says that they can tackle cricket-sized prey, and the BugLady found a picture of one with a small spring peeper.  They are ambush hunters; they don’t spin a trap webs, and they eat several times their own weight each day.

“Nursery web” refers to the female’s habit of preparing a shelter for her egg sac, which can hold 1,000-plus eggs (https://bugguide.net/node/view/24768/bgimage).  She has carried it around since she formed it, and she will conceal it when it’s about time for the eggs to hatch (https://bugguide.net/node/view/1111062/bgimage) so that the spiderlings will have shelter after they emerge.  The similar-looking wolf spiders also carry an egg sac, but they carry theirs at the rear, attached to their spinnerets; nursery web spiders carry their egg case up front, in their jaws (https://bugguide.net/node/view/277075/bgimage), and so cannot feed for the duration.  Egg sacs hatch in mid-summer; partially-grown spiderlings overwinter under loose bark, in rock piles, tree holes, etc. and mature late in the following spring.

We have spoken before about a spider Mom’s little habit of boosting the odds of her reproductive success (more young, fitter young) by grabbing a protein meal, in the person of spider Dad, immediately after mating.  And sometimes in the person of an auditioning male, if she doesn’t like the cut of his jib, or has a headache, or gets annoyed, or decides that he would serve her better as a meal than as a mate.  It’s called sexual cannibalism.

Researchers discovered that female Dark fishing spiders are so inclined, but his becoming a snack isn’t because he doesn’t absent himself quickly enough, after the fact.  For him, mating is physiologically lethal – he dies spontaneously.  He doesn’t go to waste, though, and his contribution ensures the continuation of his genes.  A female may re-mate, but a male will pay more attention to virgin females (he can tell by the scent of the silk she lays down).  All in all, an interesting take on monogamy.

Of course, there’s a video of pair mating, complete with unnecessarily intrusive music, here: https://www.youtube.com/watch?v=PUtWvbi2kTI.  Spoiler alert – tenderhearted BugFans should avert their eyes at 2:40.

This behavior/inevitability is not shared by other nursery web spiders or even by other members of the same genus.

Late last spring, the BugLady shared the boardwalk at Riveredge’s Ephemeral pond with a half-grown STRIPED FISHING/NURSERY WEB SPIDER (Dolomedes scriptus) (“scriptus” for “written,” a reference to the markings on the back of its abdomen https://bugguide.net/node/view/869686/bgimage).

Like the Dark fishing spider, the Striped fishing spider is found over much of eastern North America, but it is more wedded to wetlands than is its very similar, slightly larger, more common relative.  It’s often seen sitting on floating vegetation, its front legs on the surface film, monitoring for ripples, but here’s one with a damselfly https://bugguide.net/node/view/252108/bgimage, and there are reports of them preying on crayfish!  Say researchers Scott, Dillard, Foltz and Loughman, “The spider had ingested the majority of the crayfish’s abdomen at the time of discovery, and had used silk to anchor the crayfish to the undersurface of the rock where feeding was taking place.”

Kate Redmond, The BugLady 

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

Salutations, BugFans,

Sometimes, the secret of getting a good picture is “Right time, right place, right toys.”  The BugLady has been longing to do an episode on dung beetles – they’re amazing insects, and they live right here in Wisconsin, but clearly, she has not been in the right place at the right time, kicking over the right clods (first dictionary definition).  Thanks to BugFan Freda for pictures of an international dung beetle, which will stand in for Wisconsin species.

“Dung beetle” refers to beetles whose lives are intertwined with dung, but the term is not exclusively a taxonomic one.  True, most of its practitioners belong to the beetle family Scarabaeidae and the subfamily Scarabaeinae, but the name is also applied loosely to any beetle that makes its living in dung.  In Wisconsin, that includes a member of the Clown beetle family Histeridae and a member of the Water scavenger beetle family Hydrophilidae, who swims in dung, but whose relatives swim in water.

Researching the dung beetle is like researching a rock star.  There are True Facts, YouTube videos, Facebook, kids’ pages, and even a graphic novel or two!

Because they have Super Powers.

Like many scarabs, dung beetles are drab, stocky, and well-armored, some with a horn or an exaggerated “brow” that’s used in fighting, and with legs adapted for gripping, digging, and pushing.  They use their antennae to catch the scent of excrement.

Though they don’t especially like cold weather, dung beetles live in a variety of different habitats (deserts, grasslands, agricultural lands, and woodlands) on all continents but Antarctica.

Why are dung beetles dung beetles?  Because, as adults and as larvae, they eat and live, in and around animal droppings.  They prefer the droppings of herbivores and omnivores, which tend to be somewhat under-digested.  Adults eat the liquid portion, not the roughage, and the larvae feed on the solids.  Some species eat carnivore poop, fungi or decomposing fruits.  They don’t drink.

They meet and mate around dung.  Dung beetles are divided into three groups, depending on style – dwellers, tunnelers, and rollers.  Dwellers keep it simple – adults don’t excavate the soil or manipulate the dung, they just lay their eggs on top of a manure pile.  The larvae hatch and feed within the maturing manure pile, but the adults move to one that is fresher and wetter.

Tunnelers dig into the soil below a dung pat and make tunnels and egg chambers.  The male hauls bits of dung into the tunnels, and the female arranges them (it stays fresher underground) and lays eggs.  Both parents may stay in the manure with the larvae, and the male uses his headgear to defend his female, food and family from rival males with prolonged, underground pushing contests.  Tunnelers dodge some of the parasites and predators that find “dwellers.”

It’s the Rollers that most intrigue us.  An adult male locates a pile of good stuff (not too dry), breaks off some pieces, and compacts them, forming a ball.  This he offers to a female, and if she’s willing, they roll it away to a likely spot, watching as they go for rival beetles that may try to steal it (early naturalists thought that the other beetles were just helping the happy couple).

When they find a soft substrate, they bury the brood ball by hollowing out the space below it so it sinks into the ground.  After mating, the male leaves to sow his wild oats elsewhere, and the female makes a few more brood balls and lays a single egg in each, sealing them by smearing them with a paste of saliva, feces, and dung.  In some species, she stays to tend the grubs, which are described as “six legs and a mouth.”  She only lays a handful of eggs in her lifetime, and she works to ensure their survival!

Dung balls are also made and buried as food caches.

Dung beetles provide a variety of important ecological services (one of which is that without them we’d be knee-deep in, well,……).  They aerate the soil, recycle nutrients, improve water circulation, and disperse seeds, all of which encourages plant growth and improves conditions for grazing animals.  Fewer cow pats means less habitat for dung-loving, cow-biting flies (one cow pat can generate 3,000 flies).  And they break down and prepare the dung for species that will use it after they do.

DUNG BEETLE FUN FACTS

• Instead of searching for their supper, some smaller species ride around on their suppliers and wait for a deposit to be made.

• On the Great Plains, a wonderful owl called a Burrowing Owl (kind of the meerkat of owl species http://www.birdweb.org/birdweb/bigger_image.aspx?id=3889&type=p) collects the droppings of large grazers and places then around the entrance to its underground home.  Beetles find the dung and do their thing, and the owls have a steady supply of protein morsels.

• A dung beetle may fly 30 miles to find dung, can roll a ball that weighs up to 10 times its weight, and can bury dung that is 250 times heavier than it is in a single night.

• Dung beetles use celestial signals to chart a course from Point A to Point B.  Diurnal species roll their dung balls in a straight line, navigating by the sun (going around obstacles and then correcting).  Nocturnal species use polarized moonlight, and one species even uses the Milky Way to orient.

• In various parts of Asia, dung beetles are used medicinally or are eaten.  In ancient Egyptian beliefs, the forming, transporting, and burying of a dung ball was a metaphor for the daily renewal of the sun.

Do dung beetles light your fire?  Find out more about them in this BBC Earth video by the venerable David Attenborough: https://www.youtube.com/watch?v=Zskz-iZcVyY,

And in this TED talk: https://www.mensaforkids.org/teach/ted-connections/dance-of-the-dung-beetle/,

and in this bulletin about dung beetles in Wisconsin: https://fyi.extension.wisc.edu/wbic/files/2016/08/Dung-Beetle-Ext-fact-sheet-final.pdf,

and in this article about the amazing dung beetle-nematode connection (it’s not gross – promise): https://www.theatlantic.com/science/archive/2018/10/dung-beetles-sexually-transmitted-worms/571804/.

Kate Redmond, The BugLady 

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

Greetings, BugFans,

The BugLady heard a funny sound while she was reading the other night, the kind of small thunk, thunk, thunk that made her wonder if there might be a small leak in the roof.  After a little reconnoitering (and, mercifully, dry fingers) she traced the sound to a ladybug that was bouncing off of the inside of the lampshade by her chair.  First (live) Multicolored Asian ladybug of the year.

Please enjoy this rerun of an episode from a few years ago – some new words and new pictures.

“We didn’t do it,” say the websites of Departments of Natural Resources in a number of states, trying to make it very clear that they are NOT releasing Asian ladybugs in order to feed Wild Turkeys.  In fact, a Kentucky site declares emphatically that the state of Kentucky has never released them, but points a finger at neighbors to their South who have.  (In Wisconsin, the rumor is that the DNR stocks rattlesnakes to control turkeys – also false, on so many levels).

Multicolored Asian ladybugs (Harmonia axyridis) need no introduction – they’ve been around for a century (but especially for the last 30 years), and we know them by many names – Southern, Japanese, Harlequin, Halloween, and Pumpkin beetles, plus Aziatisch lieveheersbeestje (Holland), Asiatischer Marienkafer (Germany), and in Britain, jokingly, the Many-named ladybug.  Plus a few words that wouldn’t get past the censors.  The BugLady is intrigued by the genus name, Harmonia (which the beetle shares with a plant) but could find no explanation for it.  There are three Harmonia beetle species on our continent; all are introduced and well-established, and the Multicolored Asian ladybug is the most widely distributed.

The name “ladybug” is, of course, a bit misleading, since these are beetles (Coleoptera), not True bugs (Hemiptera), so “ladybird beetle” is more accurate.  There are close to 500 North American species in the ladybird beetle family (Coccinellidae) (from the Latin “coccinus” (scarlet) which comes from the Greek “kokkos” (berry)), and many of their lifestyles are similar.  See https://uwm.edu/field-station/ladybugs-three/ to find out more about the natural history of ladybugs.

There’s some discussion about when and how the Asian ladybug was finally established in North America.  It was brought to California in 1916 to control aphids but died off, was reintroduced there in 1964 and 1965, and it was released in a dozen Southern and Atlantic Seaboard states plus Nova Scotia between 1978 and 1982.  Each time, it did its job for a season or two, but then failed to thrive.  A number of sources cite a release in Louisiana in 1988 as the one that “took,” and the beetle subsequently traveled to almost all corners of the continent under its own steam (apparently, it doesn’t like the far, northern Rockies).  The alternate theory is that the successful colonizers arrived without fanfare in the Ports of New Orleans and Seattle and seeded themselves.  Whatever the truth, the Asian ladybug became common in the Midwest about 20 years ago, in the Northeast 25 years ago, and in the Northwest 30 years ago, and its numbers have grown considerably beyond “abundant.”  The Audubon Society Field Guide to North American Insects and Spiders, published in 1980, does not mention it at all!

On its home turf in the Far East, the Asian Ladybug feeds in forest and orchard trees, eating aphids (50 to 60 per day, say some sources, and up to 5,000 in a lifetime), and a few other small, soft insects, plus insect eggs, and it was deployed against soybean aphids in Japan (both the adults and the larvae are carnivores).  Those same soybean aphids, immigrants from Japan, made their first North American appearance – in Wisconsin, in fact – in 2000.  In the US, the beetle is used to control aphids in orchards (it’s very important to the pecan harvest), on roses and other ornamentals, and on agricultural crops including soybeans, alfalfa, corn, and tobacco, lessening the need for insecticides.  It also has a fondness for native lady beetles, and in fall, the Asian ladybug may be omnivorous.

The predators that kept their numbers in check in Asia were left far, far behind, and other than a few parasitic wasps, almost nothing goes after Asian ladybugs here.  Their red/red-and-black colors tell birds and other potential predators to think twice.  What are they advertising?  Along with some other beetles like lightning and soldier beetles, ladybugs ooze hemolymph (the insect equivalent of blood) that contains a bad-smelling, bad tasting chemical from their leg joints in order to discourage predators (it’s called reflex bleeding).  The chemical occurs in higher concentrations in the hemolymph of Asian beetles than it does in native beetles, and the Asian ladybug also manufactures a designer chemical called harmonine, which is antimicrobial.

At 5 mm to 8 mm long (9/32”), the Asian ladybug is a bit larger than its native cousins.  There are at least 16 different color phases (see http://bugguide.net/node/view/397), from red to orange to utterly plain to densely-spotted (one source said that a beetle with lots of spots is more likely to be a female).  They have reddish-brown legs, and most individuals have a black “letter” on the prothorax (the first of the three segments of the thorax) – either an “M” or a “W,” depending whether the beetle is coming or going.  The larva is likened to a tiny, spiny alligator.  In good weather with plentiful food it takes about a month to grow from egg to adult, and there are several generations per summer.  They overwinter as unmated adults – in Asia, they seek out crevices in tall, sunny, light-colored rock faces.

So – granted that this exotic beetle does a really good job of controlling equally exotic aphids on important crops, is there another side of the coin?  Let’s unpack a few sentences from the preceding narrative.

“It has a fondness for native ladybugs.”  A dramatic decline in populations of native ladybugs has followed the arrival of Asian ladybugs, simply because it’s such a super competitor.  It has no compunctions about cannibalism; it eats a lot of aphids, robbing native beetles of food; diseases that afflict native ladybugs bounce off the Asian ladybug; and it even carries a microbe that kills the competition.  In Minnesota, the populations of three native ladybugs have plummeted.  Citizen Science, anyone? http://www.lostladybug.org/participate.php.

“In fall, the ladybug may be omnivorous.”  And it especially likes to feed on sugary, ripening grapes, usually taking advantage of an opening in the fruit made by a bird or wasp.  The beetles get caught up in the harvest and pressed with the grapes, and whole batches of wine and grape juice have been tossed – even recalled from stores – due to the subsequent “ladybug bouquet.”

“They overwinter as unmated adults.”  A few sites call it a “Home Invasion.”  On warm, sunny days right after the first crisp days of fall, they look for those ancestral crevices in those ancestral light-colored cliffs and find –-the sunny sides of light-colored buildings that are insufficiently sealed, allowing entry.  They just want to be warm and dormant all winter, and then they want to leave in spring.  They don’t breed or chew on the houseplants or carpets or the dog or the dog food or the floor joists – in fact, they (allegedly) don’t feed at all.  The BugLady’s not so sure about the no-eating part because she finds them in the compost bucket and around the sticky rim of the honey jar, but maybe hers just haven’t settled down to the ascetic life yet.

Sometimes there are astronomical numbers of the things.  They swarm.  It literally “rains beetles.”  They gather by the thousands in attics and walls.  Ladybugs use a chemical attractant called an aggregation pheromone to summon a crowd, and that pheromone persists, guiding future generations to the spot.  Their hemolymph stains surfaces and their odor persists – one source describes it as the sour smell of rotting leaves (this will get us ready for the Brown marmorated stinkbug, though).

Other than the odd nip, they don’t injure humans (Cowboy up, BugFans – their “jaws” are tiny and your skin is tough), though some people are allergic to them.  One sufferer, then the head of the Entomology department at a Kentucky university, reported runny eyes and clogged sinuses after contacting the hemolymph; other people experience asthma or contact dermatitis.

Ladybugs are for sale in garden stores and websites (there are elaborate instructions about preparing the garden so that the ladybugs don’t fly away home).  Although some sites don’t say which species they’re supplying, most sell the native Convergent ladybug (Hippodamia convergens) which are captured in the wild in their winter aggregations.

DNA studies tell us that Asian ladybugs in America were introduced from Asia, but Asian ladybugs in Africa, South America, and Europe came from eastern North America!  The United Kingdom’s Ladybird Survey laments that “Despite the American experience, the animal was also released into Italy and elsewhere in Europe.”  It’s been spotted in England, and the word is out to monitor native UK species.  Humans are, indeed, slow learners.

And, yeah – we did do it.

The BugLady