Month: March 2021

During the past month, Bug of the Week’s peregrinations have visited Chilean chinchemolles, Peruvian beetles, Costa Rican arachnids, and Floridian tiger moths. This week we hop-scotch a thousand miles north to the DMV to check on the progress of Brood X periodical cicadas. During the past several weeks the Cicada Crew at the University of Maryland has been busy reassuring journalists and the public at large that, yes indeed, Brood X cicadas a.k.a The Great Eastern Brood, will appear in 15 states and the District of Columbia in the eastern half of the USA this spring. While issuing these claims, a little voice whispers something like “What if climate change or some yet unknown manifestation of the insect apocalypse has intervened in the last 17 years and cicadas don’t appear?”

To quell a bit of rising panic that prognostications of a spectacular cicada-palooza might prove false, last week we visited our favorite Brood X cicada patch to see how those rambunctious teenage cicadas were doing. The first strike of the shovel unearthed a fully grown cicada nymph. Already under construction was his escape tunnel, the passageway from the realm of darkness where he sipped xylem liquid from the roots of plants for the last seventeen years to the world of light where he will join legions of brood mates in a rambunctious mating game. This discovery is strikingly similar to a dire account published in the Annapolis gazette on April 3, 1751. An anonymous colonist wrote the following “We are informed … in some Places the Locusts have been found in great plenty, just under the surface of the Earth, almost at their full growth.  May God avert our impending Calamities!” This ominous report most likely refers to Brood XIX, a brood of thirteen-year cicadas found in what is now St. Mary’s County, Maryland, the former colonial capital of Maryland and still an important agricultural center 270 years after this account.

Seventeen years ago in the spring of 2004, periodical cicadas laid eggs in treetops. In summer, the eggs hatched and tiny nymphs tumbled to earth and burrowed down to feed on tree roots for the next seventeen years. Fast forward to 2021. Brood X periodical cicadas are now poised to exit their subterranean crypts and make a boisterous entry to the world above ground.

So, if you are concerned that periodical cicadas may not show this spring, put your fears to rest. In parts of Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia, the vanguard of Brood X periodical cicadas will make their presence known in a month or so. We will explore much more about these remarkable creatures in upcoming episodes.

Acknowledgements

The wonderful book “Periodical Cicadas: The Plague and the Puzzle” by Gene Kritsky, and the source of all things cicada, the Cicada Mania website, were used as references to prepare this episode. To learn more about Brood X periodical cicadas in Maryland, visit our 2021 Cicada Brood X information clearinghouse at https://cicadacrewumd.weebly.com/

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During the past month, Bug of the Week’s peregrinations have visited Chilean chinchemolles, Peruvian beetles, Costa Rican arachnids, and Floridian tiger moths. This week we hop-scotch a thousand miles north to the DMV to check on the progress of Brood X periodical cicadas. During the past several weeks the Cicada Crew at the University of Maryland has been busy reassuring journalists and the public at large that, yes indeed, Brood X cicadas a.k.a The Great Eastern Brood, will appear in 15 states and the District of Columbia in the eastern half of the USA this spring. While issuing these claims, a little voice whispers something like “What if climate change or some yet unknown manifestation of the insect apocalypse has intervened in the last 17 years and cicadas don’t appear?”

To quell a bit of rising panic that prognostications of a spectacular cicada-palooza might prove false, last week we visited our favorite Brood X cicada patch to see how those rambunctious teenage cicadas were doing. The first strike of the shovel unearthed a fully grown cicada nymph. Already under construction was his escape tunnel, the passageway from the realm of darkness where he sipped xylem liquid from the roots of plants for the last seventeen years to the world of light where he will join legions of brood mates in a rambunctious mating game. This discovery is strikingly similar to a dire account published in the Annapolis gazette on April 3, 1751. An anonymous colonist wrote the following “We are informed … in some Places the Locusts have been found in great plenty, just under the surface of the Earth, almost at their full growth.  May God avert our impending Calamities!” This ominous report most likely refers to Brood XIX, a brood of thirteen-year cicadas found in what is now St. Mary’s County, Maryland, the former colonial capital of Maryland and still an important agricultural center 270 years after this account.

Seventeen years ago in the spring of 2004, periodical cicadas laid eggs in treetops. In summer, the eggs hatched and tiny nymphs tumbled to earth and burrowed down to feed on tree roots for the next seventeen years. Fast forward to 2021. Brood X periodical cicadas are now poised to exit their subterranean crypts and make a boisterous entry to the world above ground.

So, if you are concerned that periodical cicadas may not show this spring, put your fears to rest. In parts of Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia, the vanguard of Brood X periodical cicadas will make their presence known in a month or so. We will explore much more about these remarkable creatures in upcoming episodes.

Acknowledgements

The wonderful book “Periodical Cicadas: The Plague and the Puzzle” by Gene Kritsky, and the source of all things cicada, the Cicada Mania website, were used as references to prepare this episode. To learn more about Brood X periodical cicadas in Maryland, visit our 2021 Cicada Brood X information clearinghouse at https://cicadacrewumd.weebly.com/

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For the last several weeks we have escape lingering chilly and dreary weather in Maryland to visit elegant phasmatids in Chile, pleasing fungus beetles in Peru, and creepy whip spiders in Costa Rica. This week we return to the good old USA and the semi-tropical warmth of southern Florida to meet a pair of breathtaking tiger moths and their similarly stunning offspring. While many tasty insects like lantern flies, beetles, and katydids depend on cryptic coloration to avoid the hungry jaws of predators, the spectacular iridescent colors of the polka-dot wasp moth and the spotted oleander caterpillar moth shout “here I am, eat me if you dare!” How then do these scaly winged harlequins escape the sharp beaks and pointy teeth of vertebrate predators? Two schemes are at play.

First, the general resemblance of these non-stinging moths to a stinging wasp probably brings pause to hungry birds that have learned to avoid making meals of painful, stinging insects. The second defense lies in the food consumed by these moths in their youth. Larvae of the polka-dot moth are known as oleander caterpillars and larvae of the spotted oleander caterpillar moths are known as … well, take a wild guess. Their diets include leaves of oleander, a beautiful but deadly woody shrub brought to the New World by European colonists.

Oleander is a toxic member of the family Apocynaceae. Leaves, flowers, and fruit of oleander are laced with heart-stopping poisons known as cardiac glycosides. We were introduced to cardiac glycosides in the Apocynaceae in a previous episode where we learned of the ability of dogbane beetles to acquire these compounds and use them as a defense against predators. Like their milkweed feeding cousins the monarch butterflies, oleander caterpillars ingest and store cardiac glycosides that are passed along to the adult stage where they serve as dietary punishment for predators attempting to eat the glycoside-laced moths. The contrasting pattern of black dots on a bright orange background of the polka-dot moth caterpillar and the white splotches on the body of the spotted oleander caterpillar, convey strong visual images and a reminder that dining on either of these caterpillars can result in disagreeable digestive consequences. Striking warning colors and patterns are called aposematic coloration, a clever strategy employed by monarch butterflies, milkweed bugs, dogbane beetles, yellow jackets, Asian giant hornets, and many other colorful insects we have visited.  

Watch as the spotted oleander caterpillar dines on an oleander leaf. Like its native North American cousin, the oleander caterpillar (larva of the polka-dot moth), the spotted oleander caterpillar consumes foliage of this poisonous woody shrub in south Florida. Noxious cardiac glycosides obtained by the caterpillar from oleander may be passed along to the adult moth to dissuade attack by hungry predators.  

The female polka-dot moth truly is gorgeous and it is little wonder that males of this species find such a beauty irresistible. But finding a mate is challenging for small moths in big world. Many female moths and other insects solve this problem by using chemical attractants called pheromones to signal their willingness to play the mating game. Most female moths release pheromones from specialized abdominal glands that help guide otherwise haplessly searching males to their connubial reward. However, the female polka-dot moth relies on yet another strategy to attract her mate.  By vibrating plates called tymbals on the sides of her thorax, the female moth creates a rhythmic clicking sound, a kind of a mothy “yoo-who” to attract a suitor. In return, the male adds his own clicks to create an ultrasonic duet. Unfortunately, their love songs are beyond the range of the human ear. However, if the lucky couple harmonizes successfully, the result of their union may be dozens of tiny orange caterpillars decorating oleander. If travel brings you to sunny south Florida for spring break or a welcome escape from a lingering winter, be sure to visit an oleander or two and perhaps you will catch a glimpse of these beautiful moths or their interesting aposematic offspring.

Acknowledgements

To learn more about the polka-dot wasp moth and the spotted oleander caterpillar moth please visit the wonderful Featured Creature articles by H.  McAuslane, “Oleander caterpillar, Syntomeida epilais…” and  “Spotted oleander caterpillar moth (suggested common name), Empyreuma pugione…”. These web pages and two fascinating articles, one by M. Rothschild and her colleagues “Cardiac glycosides (heart poisons) in the polka-dot moth Syntomeida epilais Walk. (Ctenuchidae: Lep.) with some observations on the toxic qualities of Amata (=Syntomis) phegea (L.), and another by M. Sanderford and W. Conner, “Courtship sounds of the polka-dot wasp moth, Syntomeida epilais” were used to prepare this episode. 

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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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