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As Old Man winter refuses to completely relinquish his grip on much of North America, Bug of the Week continues its adventures in warmer places. In recent weeks we visited charming chinchemolles in Chile and beautiful fungus beetles in the Amazon Basin. This week we cross the equator and head 1,750 miles north to the Osa Peninsula of Costa Rica for a nighttime encounter with one of the creepiest arachnids on the plant, the whip spider, aka tail-less whip scorpion or amblypygid. To witness the grim mien of this creature, one must don a headlamp, grab a flashlight, and plunge into the rainforest, best done with a trusty guide. Unlike distant relatives that often hunt by day, like crab spiders and jumping spiders, these denizens of the dark lurk in caves, hide in hollows beneath rocks, galleries in the soil, or holes in trees during daylight hours. By night they hunt and ambush prey. 

While other arachnids such as spiders and true scorpions amble about on four pairs of legs, whip spiders use just three pairs for their nocturnal strolls. The fourth pair of legs found at the front of the creature is extraordinarily long and loaded with sensory structures to detect odors and objects including mates, offspring, and prey. These so called “whips” can be three to six times the length of the body and give the whip spider its common name. Whips can move in almost a complete circle around the amblypygid and are very useful for detecting objects ahead, behind, above, and to the sides of the creature in a world of darkness. Just in front of the whip-like legs is a pair of scary hinged appendages known as pedipalps. Pedipalps snag prey in much the same way the powerful forelegs of the praying mantis capture their victim. As a tasty morsel enters range, a rapid strike of the pedipalps ensnares the prey in comb-like teeth. Usual meals include crickets, cockroaches, spiders and moths, but small lizards and even fish are known to be eaten by these fierce predators. Once captured, the victim is pulverized by two grinding jaws called chelicerae. Digestive enzymes are added to the pulpy mass and the whip spider ingests the liquefied meal. 

A nighttime walk along a rainforest trail is full of spooky encounters, including ones with amblypygids. Watch as the whip spider senses the approaching danger of a giant finger and jets out of harm’s way. At one tenth of normal speed see how the whip-leg of the arachnid reaches back to examine the intruder before turning on the warp drive to escape.

As frightening as whip spiders appear, they are truly harmless to humans. In fact, some species have several admirable and somewhat endearing behaviors. One such behavior is a fine sense of direction. While wandering about the rainforest at night it is easy to get lost. On more than one occasion hapless adventurers have disappeared into a ravine while searching for a trail in dense tropical vegetation. Research has shown that some whip spiders can find their way home after being moved more than 30 feet away from their refuge, all this without Google maps. For any mothers who might be reading this episode, think about the calories you burn lugging youngsters about when they want to be picked-up. Whip spiders lay from 10 to 90 eggs at a time. Mother whip spiders typically carry their young on their backs for several weeks after offspring hatch from eggs. In captivity, females of the Floridian whip spider, Phrynus marginemaculatus, continue to interact with their offspring for several months after the babes have departed from their mother’s back. Mothers were observed to move between small clusters of young ones. In captivity, females and offspring frequently engaged in gentle mutual stroking with their whip-like legs. How often these fascinating behaviors happen in the wild remains to be seen. The message conveyed by the mutual stroking is known only to the whip spider and her young, but on a dark night in the Costa Rican rainforest, a gentle touch from mom could be a comforting signal even to a whip spider.

Acknowledgements

Bug of the Week gives special thanks to Carlos and the other nocturnal adventurers at Aguila de Osa who were the inspiration for this episode. Kenneth J. Chapin and Eileen A. Hebets’ treatise “The behavioral ecology of amblypygids”, and the wonderful article “Social behavior in Amblypygids, and a reassessment of arachnid social patterns” by Linda Rayor and Lisa Anne Taylor, were used as references for this episode. To learn more about whip spiders, please visit the following website: https://theethogram.com/2018/01/23/creature-feature-tailless-whip-scorpion/

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This week Bug of the Week continues its peregrination south of the equator. Let’s head north from Villarrica volcano in Chile some 2,000 miles to the western Amazon Basin for a visit with ridiculously beautiful beetles in the rainforests surrounding the Tambopata River. These forests, some of the most diverse on the planet, receive more than 90 inches of rainfall annually. As you might expect, the massive turnover of vegetation coupled with abundant rainfall, heat, and humidity provide superb conditions for the growth of fungi. Thousands of species of fungi call the rainforest home. As fungi play an important role in recycling refractory plant materials like cellulose and lignin, they in turn provide food for a diverse horde of hungry insects. Among the most spectacular of these insects are beetles belonging to the Erotylidae clan, the pleasing fungus beetles. Pleasing fungus beetles are a large and diverse group of insects found in many parts of the world, including here in Maryland. A subset of pleasing fungus beetles known as lizard beetles are plant feeders. Those that bore into stems of legumes are considered pests. The beauties featured in this episode are members of the genera Erotylus and Gibbifer, consumers of fungi as both larvae and adults. Indigenous folks of the Tambopata call the gorgeous black, yellow, and red striped Erotylus, “ladybeetle”, a term we reserve for members of the Coccinellidae family. This dazzling beetle is also known as the zig-zag beetle. It’s funny how common names of insects mean different things in different places.

Natural wonders await discovery in rainforests along tributaries of the mighty Amazon. Brilliant contrasting colors backed by chemical defenses likely enable this delightful Erotylus beetle, sometimes known as the zig-zag beetle, to move about in broad daylight with impunity. Grooming one’s body seems to be an important pastime for these beetles.

The stunning coloration of these beetles is thought to be aposematic, distinctive coloration meant to send a warning of distastefulness to predators, in much the same way the orange and black colors of monarch butterflies and milkweed leaf beetles warn birds not to mess with them. Many species of beetles, including pleasing fungus beetles and lady beetles, can release blood from their joints and other apertures in a behavior known as reflex bleeding. A recent study of pleasing fungus beetles in Germany found a veritable witches brew of aromatic compounds – alkenes, ketones, acids, and yet unknown compounds – released as secretions from glands and in the blood of adult beetles. Several components found in the secretions and blood of the pleasing fungus beetle were repellent to an important group of predators – ants, rulers of the forest floor. These compounds also have significant antimicrobial activity, a handy defense in a microbe-packed rainforest. Although the deep rainforest is sometimes dark and dank, discovery of pleasing fungus beetles, recyclers of plant recyclers is always an illuminating experience.   

Acknowledgements

Bug of the Week thanks the crew of the Posada Amazonas for providing the inspiration for this episode. Two interesting articles “First insights into the chemical defensive system of the erotylid beetle, Tritoma bipustulata” by Kai Drilling and Konrad Dettner, and “Beetles (Coleoptera) of Peru: A Survey of the Families. Erotylidae Latreille, 1802” by Joseph V. McHugh and Caroline S. Chaboo were used to prepare this episode.

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With outdoor insect activity still agonizingly slow here in the DMV, it’s time to jump on a plane and escape the chilly rains of Maryland’s winter and discover fascinating and beautiful insects in warmer parts of the world. Let’s head some 5,000 miles south to the base of the Villarrica volcano near Pucón, Chile. In a Jurassic Park-like setting, ancient Gondwanan trees such as Nothofagus and Araucaria cling to hillsides. Here along a rushing river at the base of the volcano we discovered the giant elegant phasmatid, locally known as the chinchemolle, unabashedly grazing on clover and other herbaceous plants lining the stream bank. In previous episodes we met cryptic phasmatids from Costa Rica, Vietnam, Australia, Florida, and Maryland doing their best to look like twigs or dead leaves as they hid their somewhat long gangly bodies from the hungry eyes of predators. Unlike their shy cousins, this monster of the insect world does not attempt to hide from its predators. Oh no, just the opposite. These gaudy herbivores visually warn their enemies not to mess with them lest they risk a nasty surprise. The striking adult male elegant walking stick bedazzles onlookers with brilliant scarlet bands encircling its jet black body. White splotches at the leg joints complete a “look” designed to catch a vertebrate’s attention. The female chinchemolle, while more subtly adorned, is also striking in appearance with her army-green body ringed with orange bands.

Whether it’s a dash on a riverbank or dining on tender leaves, striking coloration of the male chinchemolle warns predators not to mess with him. Notice the opening to the secretory gland just behind its head. Defensive fluid discharged from this opening thwarts attacks by hungry predators.

While most other members of the walking stick clan try to avoid predators by mimicking plant parts and moving very slowly, these brightly colored active ground dwellers have another trick up their sleeve – or should we say, behind their head? The first segment of the thorax bears two openings leading to large secretory glands just beneath the exoskeleton of the insect. These glands produce a highly irritating, noxious ketone that can be squirted into the face of an attacking bird, lizard, or mammal. In fact, there are reports of serious eye injury to humans who looked just a little too closely at Floridian walking sticks we met in a previous episode and were rewarded with a squirt in the face. One scientific report declares that local residents of Chile know better than to challenge the chinchemolle to a stare-down, lest they risk the peril of pain and temporary blindness. However, a Bug Guy from North America could not resist handling the chinchemolle and when I stared into the eyes of the large phasmatid, it only stared back. If I wasn’t certain that insects lack eyelids, I could have sworn that it gave me a wink.     

References

Bug of the Week thanks Dr. Audrey Grez of the University of Chile for identifying the chinchemolle and providing the inspiration for this episode. The following references were used in preparation of this episode: “4-Methyl-1-hepten-3-one, the Defensive Compound from Agathemera elegans (Philippi) (Phasmatidae) Insecta” by Guillermo Schmeda-Hirschmann, and “Defensive spray of a phasmid insect” by Thomas Eisner.

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With ambient temperatures still hovering around the freezing mark, mischievous plant pests would seem months away. However, as days lengthen, the strong winter sun delivers much more energy to house plants, especially those placed near large picture windows with a southern exposure. For pests like spider mites, elevated temperatures can cut generation times by more than half. This and a few other factors we will learn in a moment contributed to a seemingly overnight explosion of spider mites on one hapless houseplant in my living room. Here’s part of the back story. When new plants arrive in a household, it’s always a good idea to give them a careful inspection just to see if they might be harboring uninvited guests. Keeping a watchful eye on new arrivals for a couple of weeks is also a good idea just to see how they are doing and observe any hitchhikers that may have accompanied them from the plant shop. Having failed to follow these ounce-of-prevention rules, a new arrival to our home recently blossomed into a spectacular outbreak of twospotted spider mites.

Mites are not insects. They belong to a related clan of arthropods, a subdivision of Arachnids called Acari. Unlike insects that have three body regions, spider mites have only two, a small region bearing the mouthparts and a large region bearing legs that comprise the rest of the body. The mite’s development starts with an egg that hatches into a 6-legged larva which molts into an 8-legged nymph. One more nymphal stage occurs before the mite sheds its skin and becomes an adult.

Twospotted spider mites are infamous worldwide as a major pariah of vegetables grown in fields and greenhouses, large and small fruits, ornamental trees and shrubs, and herbaceous ornamental plants, including those growing in front of my picture window. These cosmopolitan rascals feed on more than 200 plant species worldwide. They injure plants by piercing cells with tiny needle-like stylets that rupture cell membranes. Nutritious cell contents are then sucked into the digestive tract of the mite. By removing the green photosynthetic contents of cells, tiny white spots accrue on the leaf surface, creating a type of injury called stippling. When spider mites are abundant and their feeding prolonged, leaves may turn white as thousands of stipples coalesce. Eventually leaves discolor and may turn yellow, bronze, or brown before dropping from the plant. Heavily infested plants often appear to have encountered a blowtorch.

One fascinating and unique attribute of spider mites is their ability to produce silk. Super strong silk fibers function as mite highways connecting one part of the plant to another. Silk also provides a protective refuge from predators and adverse climatic conditions and acts as a substrate for depositing eggs and communicating with other members of the species.

In the warmth of a sunny window, populations of twospotted spider mites explode. A cloak of fine silk spun by thousands of spider mites provides a highway for the tiny suckers to move from one branch to another. In addition to transport, silk provides a refuge from predators and the perfect place for spider mites to deposit translucent spherical eggs. Heavy infestations like this one are often best resolved by disposing of a plant before mites spread to others.

Under natural conditions outdoors, twospotted spider mites are beset by attacks of predatory ladybeetles, lethal minute pirate bugs (arrrggghhh!), maniacal lacewing larvae, and predatory mites, among other beneficial insects. Unfortunately, these heroes are conspicuously absent from my living room. With thousands of spider mites already sucking the life from my plant, legions of mite eggs ready to hatch, generation times growing ever shorter in the strong winter sun, and a dozen uninfested house plants cowering nearby, the hapless house plant has now joined the remnants of last season’s vegetables in the compost pile. In a final act of contrition, plant and pests will fuel generations of microbes and decomposers like pillbugs and soldier flies we met in previous episodes in an ongoing circle of life.

Acknowledgements      

Fascinating articles including “The silk of gorse spider mite Tetranychus lintearius represents a novel natural source of nanoparticles and biomaterials by Antonio Abel Lozano-Pérez, Ana Pagán, Vladimir Zhurov, Stephen D. Hudson, Jeffrey L. Hutter, Valerio Pruneri, Ignacio Pérez-Moreno, Vojislava Grbic’, José Luis Cenis, Miodrag Grbic’ & Salvador Aznar-Cervantes”, and “ Featured Creatures, Common name: twospotted spider mite scientific name: Tetranychus urticae Koch (Arachnida: Acari: Tetranychidae)” by Thomas R. Fasulo and H.A. Denmark were consulted in preparation of the episode. Learn more about twospotted spider mites at this link: http://entnemdept.ufl.edu/creatures/orn/twospotted_mite.htm

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This week let’s time travel a little bit. Not the teeny, across the centuries travels Claire Fraser undertakes in Outlander. Nah, let’s journey back hundreds of millions of years long before T. rex walked the earth to the ancient origins of insects. In times when giant tree ferns ruled earth’s forests, primordial relatives of silverfish, the Triassomachilidae, foraged for starchy remains of plants on the verdant forest floor. Now fast forward several hundred million years to last Tuesday, when a handsome silverfish appeared at 6:10 am on the bathroom wall. With ancient decaying tree ferns conspicuously absent from my home, I wondered what delicacies silverfish discover inside a residential dwelling.

Among the most ancient of insects are the silverfish. On rare occasions I am graced by their presence early in the morning on my bathroom wall or maybe in the sink. My catch and release policy ensures they can find more natural surroundings when I release them outdoors.

Actually, we share many carbohydrate-rich food sources with plants found at the time of the world’s first silverfish. Modern food on the silverfishes’ menu include those high in starchy materials such as the cellulose found in paper goods and glue, the kind you were told not to eat in first grade, the glue that binds pages of books together. It is not surprising then, that some species of silverfish are important pests in libraries and museums where starchy materials abound. Other tasty treats for silverfish include natural fabrics such as linen, silk, and cotton, cereals, preserved meat, and dead insects, including other silverfish. Of course, in the geological time scale, frame houses are a fairly recent contrivance and typical natural habitats for silverfish are decaying logs and leaf litter, caves and crevices, and, for some species, ant nests.

The name silverfish was coined in part from the silvery scales found on the insect’s exoskeleton. The “fish” part apparently refers to the resemblance of the silverfish’s scales to those of fish. If you find silverfish scurrying around your home and wonder about the source, have a close look in dark, damp corners of the basement or other places where books or garments might be stored. Infested books or clothing can be placed in plastic bags and deposited in a freezer for a few days to kill attendant silverfish. Silverfish also thrive in conditions of high humidity and dehumidifiers placed in damp rooms may help reduce the suitability of these locations for silverfish. Removing clutter, storing books and garments in airtight containers, and vacuuming closets and storage areas will also help reduce populations of silverfish and other nuisance pests around the home. So, where is the wellspring for my silverfish? Well, just beneath my bathroom floor lies a pantry used to store paper goods and other household items. Sometimes it is a bit musty and maybe it could use a more regular visit with a vacuum. But, I have to admit, there is something remarkable about a morning greeting by a creature older than dinosaurs. I usually just catch these old timers in a paper cup, warn them to socially distance especially when predators are near, and release them in the wild.  

Acknowledgements

To learn more about silverfish, please check out the fascinating fact sheet “Common name: silverfish, scientific name: Lepisma saccharina Linnaeus (Insecta: Zygentoma: Lepismatidae), Introduction – Distribution – Description – Life Stages and Biology – Hosts – Economic Importance – Survey and Detection – Management – Selected References” by Eleanor F. Phillips and Jennifer L. Gillett-Kaufman. It can be found at this link: http://entnemdept.ufl.edu/creatures/URBAN/silverfish.HTM

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Next weekend we celebrate Valentine’s Day, a day named in honor of a third century Italian saint commemorated throughout the centuries by exchanging notes of love, romance, gifts of flowers and candy, and boatloads of affection. Several amorous characters take center stage in this Bug of the Week. Whether it’s a horny male Hercules beetle out for a romp on a stump, wheel bugs enjoying an intimate dinner of fall webworm caterpillars, or teenage cicadas celebrating a day in the sun after seventeen years underground, conjugal visits abound in the insect world. Let’s find out why.

For many animals, copulation is a short-term affair, measured in mere minutes or sometimes fractions thereof. However, insects depicted in this episode linger long with their mates, in some cases copulation lasts for hours and even days. Red-shouldered bugs we met in a previous episode may copulate for eleven days. How exhausting! Prolonged copulation and post-copulation “riding” of a male on the back of its mate is common in many orders of insects. By denying interlopers access to a female, prolonged mating and post-copulatory guarding by the male helps ensure that his sperm will be the ones which fertilize his mate’s eggs. In the world of insects, often the last mating before eggs are laid is the one that counts. This likely explains the oft observed pairings of so many male and female insects.  

Long before Disney coined the term “Love Bug” for a rambunctious Volkswagen beetle, denizens of Florida and the Gulf states knew of another kind of lovebug. The Floridian lovebug is a small fly with a red thorax and black body and wings. The name “lovebug” derives from the fact that these small flies are often found intimately entangled. Lovebugs belong to a family called the Bibionidae. As larvae, bibionids eat decaying plant material and are important decomposers like isopods we met in a previous episode. After completing development in the soil, they pupate and emerge as adults. Adult flies do not bite or sting, but vast numbers emerge in spring and fall creating a real nuisance to residents in southern states. In addition to entering homes and bumbling about the garden, lovebugs splatter windshields of cars and trucks creating hazardous driving conditions. They become numerous enough to clog radiators of cars, causing them to overheat. One way to avoid these lovers is to drive in the late afternoon or evening when lovebugs are less likely to take wing.

Many Insects have prolonged copulation and often males guard their mates for hours or days following copulation. Just for fun, let’s look at a few. From first to last, they are: Damselflies coupled in the “heart” position for long periods of time; conjoined spur-throated grasshoppers basking in sun; camera-shy periodical cicadas that will appear by the trillions this spring when Brood X appears; peripatetic milkweed bugs playing push me, pull you; gorgeous dogbane beetles enjoying dinner and a date on their heart-stopping host; male margined carrion beetles engaging in shaky business with their mates; female thread-waisted wasps dining on pollen while their mate hitches a ride; and adorable male horn-faced mason bees fending-off suitors while guarding their betrothed.  

With respect to kissing and kissing bugs, many would agree that kissing ranks right at the top when it comes to affection. However, the kiss of the kissing bug can be oh, so much more than that. Kissing bugs belong to a family of sucking insects called assassin bugs. Assassin bugs are predators, predators with long beaks which they use to suck blood from many other kinds of animals. Kissing bugs take the act of predation one step further. Their primary source of food is the blood of vertebrates, including mice, dogs, and humans. During the day, kissing bugs hide in crevices in plaster, cracks between boards, or in gaps in thatched roofs. At night, these little vampires leave their refuge and quietly seek unsuspecting humans to suck their blood. They may feed on any exposed body part, but look out, their dining preferences swing to tender tissues on people’s faces, especially the lips, hence the name kissing bugs. In southern Texas, Central and South America, kissing bugs are common. For most people the bite of the kissing bug may go unnoticed, or it may leave no more than a small red mark. But for those allergic to the saliva of kissing bugs, itchy welts, rashes, and swelling can occur. As with the introduction of any foreign protein into the body, anaphylactic reactions are a concern. A greater worry associated with kissing bugs is their ability to vector a nasty parasite called Trypanosoma cruzi, the causal agent of a sometimes fatal disease called Chagas disease. The parasite is ingested by the kissing bug as it feeds on an infected animal. Carried in the gut of the kissing bug, the parasite issues forth when the kissing bug defecates on a victim’s skin. An abrasive scratch by the victim or a small puncture in the skin allows the parasite to enter the body and wreak havoc. How disturbing! While most common in regions of Central and South America, kissing bugs can be found as far north as Pennsylvania on the east coast and California on the west coast. If your adventures take you to rural areas of Mexico, Central or South America where Chagas disease is endemic, always sleep inside your netting and remember, no kissing the kissing bugs, even if it is Valentine’s Day!

Acknowledgements

The intriguing article “The adaptive significance of mate guarding in the soapberry bug, Jadera haematoloma (Hemiptera: Rhopalidae)” by Scott P. Carroll, the great Featured Creature fact sheet “common name: lovebug scientific name: Plecia nearctica Hardy (Insecta: Diptera: Bibionidae) Introduction – Classification – Distribution – Description – Key to the Species – Dilophus sayi – Behavior – Hosts – Economic Importance – Management – Selected References” by H.A. Denmark and F.W. Mead,  and the CDC Chagas disease website were consulted to prepare this episode. Bug of the Week thanks Marcia Shofner for the inspiring this heart-warming Valentine’s Day episode.

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This week we turn to the Bug of the Week mailbag where we received a picture of an unusual winter-active insect found on the trunk of a tree. Let’s visit stoneflies, curious amphibious insects whose lives are split between two worlds; a life aquatic in their youth and romantic interludes on land as adults.  While many insects migrate or enter a hibernal torpor called diapause during this frosty season, winter stoneflies are in their glory. Special compounds including glycerol, proteins, and sugars act like antifreeze and prevent stoneflies from freezing to death as they cavort on snow covered stream banks. These ancient insects can be found on stones, vegetation, and bridges near small, fast-moving streams. These week’s star was sighted in a nursery near a major river in western Maryland loitering on the bark of a tree. 

Adult winter stoneflies are dark brown or black and are active day and night. In their youth, stoneflies live in fresh water, rushing streams and rivers. Juvenile winter stoneflies, called nymphs, graze on submerged aquatic vegetation or decaying organic matter. Other species have abandoned a vegan diet and eat aquatic insects, including other stoneflies. Stonefly nymphs obtain oxygen from the water through delicate gills lining the neck, thorax, or abdomen. Most immature insects shed their skin or molt just a few times as they develop. However, some species of stoneflies may molt more than 20 times before leaving the water as adults in search of mates. The remarkable transformation from nymph to adult transpires at the edge of the stream as the nymph emerges from the water and latches onto a stone, log, or plant. The exoskeleton splits along the midline and the adult stonefly emerges like a wraith from the cast skin. When the exoskeleton hardens, adults walk and fly to find mates. As adults, food choice differs on a species basis. Some eat lichens, algae, or vegetation, but others gain all necessary nutrients as nymphs and never feed as adults. Winter stoneflies are relatively weak fliers and seem to prefer walking and running to flying. However, other species of stoneflies are good fliers and are attracted to porch lights and, unfortunately, bug zappers.

Stonefly courtship is a curious matter. A hopeful guy stonefly strikes the surface of a resting place, such as a small branch or a stone, with its abdomen to create a specific drum beat. If a female of the same species is nearby and favorably impressed by his rhythm and sound, she will drum a reply with her abdomen. The percussive duet continues and if both like what they sense, the deal is sealed and they mate. After mating, the female stonefly will swoop to the surface of the water to deposit her eggs. This is a season of joy for fish living in stonefly laden streams. Trout, steelhead, and other freshwater fish find stonefly nymphs and adults delectable. Both adult and juvenile stoneflies are an important source of food for denizens of our streams. Fisherman have taken advantage of this passion and created a variety of lures that mimic stoneflies with colorful names like Montana Stone Yellow and Henry’s Fork Yellow Sally.

Plucked from a riverbed, a stonefly nymph dashes to return to its watery realm. Shed skins of stoneflies cling to logs and stones near riverbanks where nymphs molt and become adults. On wintry days, males roam icy landscapes and even slowly moving humans in search of mates. Male stoneflies drum their abdomen on substrates including small branches and stones along the river to attract a mate. While inaudible to the human ear, a receptive female will catch his vibe and signal her willingness to mate by returning his percussive performance with one of her own. Who says drummers aren’t romantic?

Stoneflies are also important indicators of water quality. Streams with heavy sediments, low oxygen content, or pollutants do not support a diversity or abundance of stoneflies. Stoneflies emerging from your local stream are a positive sign of a healthy environment. So, during the next couple of weeks, take a walk on a sunny afternoon and visit a small stream or river to seek the stonefly. The best viewing is when stream banks are covered with snow and stoneflies clamber from the chilly waters below. The winter stoneflies featured in this Bug of the Week were observed on warmish afternoons on a small footbridge spanning the Little Patuxent River in Columbia, Maryland, on the Billy Goat Trail along the mighty Potomac River in Maryland, near the Monocacy River in Frederick County, Maryland, and along the banks of Pidcock Creek near Lambertville, Pennsylvania.

References

Bug of the Week thanks Steve Black for sharing his great image of a winter stonefly discovered on a tree-trunk. The fascinating book “Aquatic Entomology” by W. Patrick McCafferty was used as a reference for this Bug of the Week. Here is a link to a really nice article detailing the stonefly’s clever strategies for surviving winter: https://blogs.scientificamerican.com/guest-blog/winter-stoneflies-sure-are-supercool/

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By some unusual circumstance, Bug of the Week escapes the chilly confines of the Maryland winter and visits scenic Zion National Park and the Great Basin Desert, where we encounter entertaining and unorthodox darkling beetles called desert stink beetles. You’ll remember last week we met cousins of these gymnastic beetles called forked fungus beetles as they battled for possession of bracket fungi and potential mates. 

On the desert floor as day waned, these large and very juicy scrumptious looking darkling beetles appeared and wandered about feeding on vegetation with impunity. At close to an inch in length, these jet-black behemoths were highly conspicuous against the light red desert earth. With hungry predators such as lizards, birds, and rodents roaming about, the desert is a dangerous place for large, tasty-looking insects. As I crouched to photograph a beetle, it halted, stood on its head and lifted both pair of hind legs off the ground like some contortionist from Cirque du Soleil. What manner of trick was this? As I examined the creature a bit more closely with my fingers, my reward was a distinctly unpleasant odor emanating from the rear end of the bold beetle. Later my fingers turned a curious shade of brown where chemicals squirted by the beetle reacted with the air and my skin. 

Defenses of the desert stink beetle: First, when you see a human with a camera, run for grassy cover. Second, if he has you cornered and pokes at you with his giant finger, stand on your head and kick at him. Third, if all else fails, just lie on your back, legs in the air, play dead, and maybe the idiot will get bored and leave you alone. That worked.

This marvelous denizen of the desert was a darkling beetle in the genus Eleodes. Eleodes has evolved an elegant defense against other animals that would like to make it dinner. Dr. Thomas Eisner discovered that within the abdomen of Eleodes two large glands produce several types of quinones and other organic compounds. These noxious chemicals cause extreme irritation to mucus membranes such as those lining the mouth and eyes of predators like birds and toads. Quinones are also repellent to hard-core invertebrate predators like ants. Eisner suggested that the “headstand” routine may serve as a warning to would-be attackers to leave Eleodes alone or suffer the irritating consequences. It appears that at least one crafty desert predator, the grasshopper mouse, has devised a way to circumvent the beetle’s defense. Upon encountering its prey, the grasshopper mouse flips the beetle around and jams the beetle’s rear end into the soil. With the beetle’s chemical defenses shooting harmlessly into the dirt, the grasshopper mouse consumes the beetle, starting with the head, of course. When it comes to dining on Eleodes beetles, the grasshopper mouse has learned that one bad turn deserves another. 

Acknowledgements

We thank Mike, Brian, Anne, and Jim for the inspiration for this Bug of the Week, and  Dr. Shrewsbury for wrangling stinky beetles. The wonderful book “For Love of Insects” by Thomas Eisner served as a reference for this episode.

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Wood is composed of several compounds but, most notably, two really tough polymers you probably have heard of called cellulose and lignin. Fungi are one of but a few organisms able to breakdown these carbon-rich compounds and return these molecules to food webs. Without fungi recycling fallen trees, our forests would cease to exist as the dynamic wonderlands we enjoy today. Fungi turn wood into hyphae and fruiting bodies which in turn become food for creatures higher up the food web, including hundreds of species of insects. This week Bug of the Week dives into the email bag to share some marvelous images of really cool beetles whose lives depend on fungi as a source of food and as a stage for romance.

The forked fungus beetle belongs to a large family of beetles called darkling beetles, Tenebrionidae (previously we met other members of this clan in their winter refuge beneath the bark of a tree).  As their name implies, both larval and adult forked fungus beetles consume and thrive on nutrients contained in the tissues and spores of fungi. Bracket fungi in the genera Ganoderma and Fomes are reported to be favored hosts. Female beetles deposit eggs on the surface of the bracket fungus and larvae tunnel in and feed on nutritive hyphae. The forked fungus beetles we meet today were photographed in September 2020 on the surface of the bracket fungus where courtship battles often take place. The large horns curling above the head of the fungus beetles occur only on males. They play a key role in competitive interactions with other males for opportunities to mate with very cute but hornless female beetles.  Male beetles can often be found guarding bracket fungi where they chase away other males, potential rivals, and thereby monopolize the critical resource needed by females to lay eggs. One study found that males with larger horns had a greater chance of mating success than males with smaller horns.

Combat between two forked fungus beetle (Bolithoterus cornutus) males. The larger attacking male uses his clypeal horns in an attempt to dislodge the smaller male. The smaller male was previously courting the female and during the combat grips her with all six legs. The video has been sped up to 5x actual speed. Please visit the source of this video in the following amazing article: K.M. Benowitz, E.D. Brodie III, V.A. Formica (2012) Morphological Correlates of a Combat Performance Trait in the Forked Fungus Beetle, Bolitotherus cornutus. PLoS ONE 7(8): e42738. https://doi.org/10.1371/journal.pone.0042738

In addition to the prominent horns curling above the head of the male, a smaller pair of horns is present near the eyes at the front of the beetle’s face. So, other than looking marvelous, of what use are the horns? As part of the mating ritual, a male beetle will climb atop his mate and guard his intended for up to five hours while intermittently attempting to mate with her. Scientists have observed amorous male beetles using their two sets of horns “like a wedge and a bottle opener” to dislodge already engaged males from the female and thereby assert themselves as the winning suitor. In this battle to procreate, scientists have found that large beetles, ones with larger horns, are stronger than smaller beetles. Their powerful grip may make big beetles with big horns more difficult to dislodge from their mate than smaller males with puny horns.  In forked fungus beetles and many other animals, yes, size does matter.

Acknowledgements

We thank Cathy Keifer for providing the inspiration and marvelous images used in this episode. The remarkable articles “Morphological Correlates of a Combat Performance Trait in the Forked Fungus Beetle, Bolitotherus cornutus” by K.M. Benowitz, E.D. Brodie III, and V.A. Formica, and “Common name: forked fungus beetle (suggested common name) Scientific name: Bolitotherus cornutus (Panzer) 1794 (Insecta: Coleoptera: Tenebrionidae)” by Ummat Somjee and Andrea Lucky provided information used in this episode. Please learn more about forked fungus beetles at the following links:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0042738

http://entnemdept.ufl.edu/creatures/misc/beetles/forked_fungus_beetle.htm

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On chilly days, most small invertebrate creatures like insects are locked in winter torpor awaiting spring’s warmth. However last week, following a nighttime low in the teens and with hoar frost still on the ground, I was delighted to see a gang of pillbugs, a.k.a. rollie pollies, sowbugs, potato bugs, or woodlice, slowly going about their task of recycling organic matter beneath a large bolt of a fallen ash tree. Unlike predators such as lady beetles or praying mantises that occupy exalted places high in the food webs, detritivores occupy lower rungs on the ladder of life. Detritivores are key players in Mother Nature’s clean-up crew. Their important task is to eat dead and decaying things such as fallen plants and return minerals locked-up in leaves, fruits, and woody tissues to the nutrient cycle. We visited other recyclers in previous episodes including rhinoceros beetles, millipedes, termites, and bess beetles.  

Early one morning, with frost still on the ground, a scrum of pillbugs huddles beneath a log. As the early morning sun warms their bodies, fourteen legs help them skitter from the sunlight to find danker refuge beneath the bark.

Isopods are not truly bugs, so please excuse their guest appearance in Bug of the Week, but they are odd and fascinating members of the arthropod clan. They belong to a group of hard-shelled creatures called the crustaceans. Crustaceans include tasty, familiar edibles like crabs, lobsters, and crayfish. Isopods commonly occur in marine environments where they eat algae, diatoms, and decaying vegetation. Eons ago, some adventurous members of the isopod lineage moved from the sea to the land. These explorers were the ancestors of the isopods commonly found beneath logs in the forest and those in my compost heap. Most gardeners know these curious creatures by the names pillbug or sowbug (a closely related terrestrial crustacean). The name pillbug stems from the ability of many species of these isopods to roll into a pill-shaped ball when threatened much like an armadillo. This defensive posture makes the tender underbelly of the pillbug difficult to reach. Armor-like plates on its back shield the pillbug from attack.  

With the return of warm weather, pillbugs will once again begin the important job of recycling my leftover vegetables. And in this taste test, it looks like carrots are preferred to tomatoes.

Pillbugs are common in moist habitats beneath leaf litter, compost, rotten logs, boards, and stones. Moisture is a key element in the life of isopods. Even though they have escaped the confines of a life aquatic with their colonization of land, these true crustaceans still rely on gills for the exchange of oxygen and carbon dioxide and those gills must remain wet. Unusually wet seasons like ones we have experienced in recent years create favorable conditions for explosions of pillbug populations. While pillbugs and sowbugs play an important role as recyclers, when too numerous they may damage the tender roots and stems of plants in greenhouses or gardens. Folks sometimes are dismayed when pillbugs appear in basements or garages as they move about in search of dead things. You can thwart entry of pillbugs into your home by using a few simple tricks: keep mulch away from foundations, maintain door sweeps, and caulk openings to discourage unwanted visitors from entering your home. With the return of warm weather in a few months, my compost heap will be a smorgasbord of rotting vegetables and, without fail, pillbugs will appear from the moldering depths of the bin eager to recycle plant remains. 

 Acknowledgements

We thank Dr. Shrewsbury for wrangling lumber, photographing pill bugs, and providing inspiration for this Bug of the Week.

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