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Last September we caught up the spotted lanternfly, one of the most important recent invaders of crops and landscape plants in the eastern United States. We learned about its detection in the US in 2014 in Berks County, Pennsylvania, crop damage and despair associated with lanternfly infestations, and how immature stages and adults are moving throughout our land. This year, while humans were struggling with the rampant spread of the Delta variant of Covid, lanternflies were engaged in their own astonishing spread throughout our land. Locally in the DMV, the number of infested counties went from two on September 23, 2020 to six on September 7, 2021, and Maryland saw an even greater number of infestations with a jump from two infested counties in 2020 to nine in 2021. Far-flung infestations have popped up hundreds of miles distant from the initial infestation in Berks County, PA and have appeared in Indiana, Ohio, and New York this year. Isolated detections of individual lanternflies have been found almost 500 miles from Berks County in Henderson County, North Carolina.       

How do spotted lanternflies move about? Entomologists at Penn State have found flight-incapable immature stages of spotted lanternflies able to travel hundreds of feet in their quest for food. Scientists at Cornell suggest that on their own, lanternflies can move 3 to 4 miles by walking, jumping, and flying. So, if self-initiated lanternfly dispersal is limited to a matter of miles, how are isolated individuals discovered and infestations generated hundreds of miles from the generally infested area in the mid-Atlantic? According to entomologist Julie Urban at Penn State, the most likely explanation for these long-distance peregrinations lays in human-assisted transport of lanternflies, especially lanternfly eggs. It is believed that spotted lanternflies arrived in Pennsylvania around 2012 from Asia, a trip of some 7,000 miles, in a shipment of stone products bearing lanternfly egg masses. Unlike many herbivorous insects that lay eggs on food plants of their young, spotted lanternfly mothers deposit egg masses on non-host objects including stones, cinder blocks, lawn furniture, and vehicles, in addition to trees.  These nondescript egg masses are easily overlooked on natural and human-made items and easily transported inadvertently by road or rail. Unfortunately, at the epicenter of the spotted lanternfly infestation in southeastern Pennsylvania, Delaware, and New Jersey, several major interstate highways and railways run north and south, east and west, crisscrossing a region replete with warehouses, truck stops, and railroad depots embedded in a matrix of orchards, vineyards, and forests that serve as hosts for lanternflies.  Unfortunately, recent climatic data from the US and Asia suggest that much of the mid-Atlantic and Central regions of the US and portions of California, Oregon, and Washington State have climates suitable for the survival of spotted lanternfly.  

From September to December, spotted lanternflies can be found resting and feeding on tree bark and depositing eggs covered with white or grey wax. By late winter and early spring much of this protective cover has worn off and changed color to tawny brown or grey. Early stages of lanternfly nymphs are black with white speckles and in the final nymphal stage, they are red with black patches and brilliant white spots. From now until the arrival of lethal temperatures, they will be seen on a wide variety of trees. If you spot spotted lanternflies in your landscape, please report your sighting to your state Department of Agriculture or University Extension Service. Video by Mike Raupp and Mauri Hickin

Is there any good news in this unsavory story? You bet. Just as many of our indigenous beneficial insects ganged up to put a beat down on brown marmorated stink bugs, several of the same good guys – spiders, mantises, assassin bugs, and parasitic wasps – have added spotted lanternfly eggs, nymphs, and adults to their menus. Even more exciting is the discovery of two naturally occurring pathogenic fungi, Batkoa major and Beauveria bassiana, responsible for collapsing an infestation of spotted lanternflies near Reading, Pennsylvania in 2018. These and other fungi are showing great promise as mycoinsecticides that can be applied by growers and homeowners to control lanternfly nymphs and adults.

Will spotted lanternflies soon be coming to your neighborhood? Maybe so, and officials in several states are urging citizens to report sightings of spotted lanternflies to your state Department of Agriculture or University Extension Service.

To learn more about spotted lanternfly, please visit these links: 

https://extension.psu.edu/spotted-lanternfly

https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/spotted-lanternfly-ipm/biology-life-cycle-identification-and-dispersion/

https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/spotted-lanternfly-ipm/management-predators-and-parasitoids/

https://www.washingtonpost.com/weather/2021/09/13/spotted-laternfly-invasive-trees-midatlantic/

Acknowledgements

Bug of the Week thanks Kevin Ambrose for providing the inspiration for this episode and Dr. Shrewsbury for spotting and wrangling spotted lanternflies. Mauri Hickin graciously provided the image of the early instar nymphs. We acknowledge the great work of scientists contributing to our knowledge of this pest with particular thanks to authors of articles and aforementioned websites used as references, including “Perspective: shedding light on spotted lanternfly impacts in the USA” by Julie M. Urban, “Dispersal of Lycorma delicatula (Hemiptera: Fulgoridae) Nymphs Through Contiguous, Deciduous Forest” by Joseph A. Keller, Anne E. Johnson, Osariyekemwen Uyi, Sarah Wurzbacher, David Long, and Kelli Hoover, “The Establishment Risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and Globally” by Tewodros T. Wakie, Lisa G. Neven, Wee L. Yee, andZhaozhi Lu, and “Applications of Beauveria bassiana (Hypocreales: Cordycipitaceae) to Control Populations of Spotted Lanternfly (Hemiptera: Fulgoridae), in Semi-Natural Landscapes and on Grapevines” by Eric H. Clifton, Ann E. Hajek, Nina E. Jenkins, Richard T. Roush, John P. Rost, and David J. Biddinger. Thanks to Brian Eshenaur and the entire team at the New York State Integrated Pest Management Program of Cornell University for providing the updated maps of spotted lanternfly in the US.

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During the waning weeks of summer, messages pour in about large hornets bumping into windows at night, stripping bark from trees and shrubs, or simply frightening folks with their presence. Throughout the last two years, these giants of the wasp world were often mistaken for dreaded “murder hornets”, an invasive scourge of honeybees and beekeepers in the Pacific Northwest. Ergo, now is a good time to visit another foreigner, the European hornet, that calls the United States home. European hornets first appeared in the US in New York sometime between 1840 and 1860.These predators spread and now occupy territory from the east coast to the boarders of the Dakotas. In nature, European hornets use a tree cavity as the location for a nest, but occasionally, as was the case with my neighbor across the street, hornets will nest in a wall void.

The colony is founded by a single queen that survives the harsh winter beneath the bark of a fallen log or in a similar protected location. In spring when warmer temperatures return she becomes active, gathering bark from trees, constructing a small paper nest, and laying eggs destined to become workers. After the queen successfully raises her first batch of sterile female workers, she remains in the nest producing brood while her daughters take up the tasks of enlarging the nest, protecting it, and gathering food for the young. Caterpillars, flies, cicadas, grasshoppers and other stinging insects like yellowjackets are all on the menu. European hornets are somewhat unique from other clan members such as yellowjackets and baldfaced hornets in their foraging behaviors. European hornets hunt at night. They are also attracted to light and can be found buzzing around porch lights or heard crashing into windowpanes after dark. Several times this past month while reading in bed, European hornets were the “things that go bump in the night” at my bedroom windows.

In addition to eating other insects, in late summer and early autumn European hornets readily dine on fallen fruit and sap fluxes on tree bark. They engage in a somewhat unusual behavior of feeding on plant tissues beneath the bark of trees and shrubs. A visit to one of my neighbor’s lilacs revealed mischievous European hornets stripping bark and greedily lapping exudates leaking from the wound. This annoying behavior has been observed on many types of trees and shrubs including lilac, rhododendron, ash, and birch. Unfortunately, small trees and shrubs can be severely damaged by this behavior. Many stinging insects feast on the sweet bounty of fallen fruit beneath trees. To reduce chances of a sting by a European hornet, yellowjacket, or wasp, don protective gloves and carefully pick up fallen fruit and compost it if it poses a risk. Wear shoes rather than going barefoot when you walk near fruit trees.

Tree hollows are typical nesting sites for European hornets in the wild. Cicadas and other insects serve as protein sources for developing larvae back at the nest. Hornets often imbibe liquid nutrients from sap fluxes on tree trunks. Powerful jaws strip bark from trees to be used in nest construction and also to expose nutritious tissues just beneath the bark. Bark feeding is common on many trees and shrubs in late summer and early autumn. To get up close and personal with these hornets, wait until late autumn when stingless drones can be found.

During autumn, the hornet colony operates at a fevered pace. Inside the colony, the queen no longer produces sterile daughters. She has shifted production from workers to female and male hornets. Females are destined to become queens of future generations. Males have just one purpose and that is to mate with the new queens. After fulfilling this biological imperative, males die. As autumn wanes, the colony is abandoned and queens find protected places to spend the chilly months of late autumn and winter. The nest will not be reused in subsequent years.

Although these hornets are large and scary looking, humans are unlikely to be stung by European hornets. I have photographed and video-recorded these gentle giants at a very close range and other than receiving an inquisitive stare, I was unmolested. To avoid being stung, simply avoid disturbing the nest site or the hornets. If European hornets have nested in a home or another location that poses a threat to human safety, they may be exterminated. Assistance from a professional may not be a bad idea. However, if the nest is out of harm’s way, I favor the approach of my neighbors who had a “live and let live arrangement” with these giants that had taken up residence in a wall void of their home. They decided to give the nest a respectable berth and simply enjoy the comings and goings of these spectacular insects.

Acknowledgements

Special thanks to many Master Naturalists and homeowners for sending images of European hornets, which served as the inspiration for this episode. Thanks to Dr. Shrewsbury for sharing videos of European hornets, Harry for directing me to his pillaged lilacs, and to Brooke and Ruth Ann for sharing a ginormous hornet’s nest that once resided inside their wall.

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While much of the nation roasts through stifling heat waves this summer, it is hard to believe that any creature could struggle with cool temperatures. But remember from your high school biology days that many animals are poikilotherms, cold-blooded beings whose body temperatures largely depend on the ambient temperature of the environment they occupy. Terrestrial creatures including amphibians like frogs, non-feathered reptiles like snakes, and, of course, insects fit into the category of cold-blooded animals. However, to perform fundamental activities of locomotion either by legs or wings, muscles of cold-blooded insects must reach a minimum temperature to function. For example, take butterflies – in cool montane habitats of the Sierra Nevada, flight muscles in a butterfly’s thorax may require temperatures in the 90’s to sustain flight. One way to generate this level of heating is to bask in the strong mountain sunshine. Basking is a thermoregulatory behavior used by many insects and other poikilotherms to gather energy and warmth to facilitate metabolic processes and sustain activities such as walking and flight.

As homeotherms, that is, warm-blooded creatures, we have behaviors and the metabolism to help keep our body temperatures at optimal levels. One familiar way to keep warm is shivering, rapid involuntary contractions of our muscles that expend energy and generate heat to warm our bodies when we are cold. Do insects employ shivering or something akin to shivering as a way to warm up? You bet! Enter a chilly dobsonfly. Each year about this time, Bug of the Week receives requests to identify a large creepy looking insect found on the side of a building or on a plant, often near a porch light that attracts flying insects. These grotesque marvels belong to an order of insects known as the Megaloptera – “huge winged” insects – and go by the name of dobsonflies. They are among the largest winged insects found in the DMV, ranking in size with large moths and butterflies.

On a recent chilly morning on Cacapon Mountain, West Virginia when temperatures had dropped into the low 60s the night before, I spotted a magnificent female dobsonfly resting on a railing near a porch light. Apparently, temperatures in the upper 70s at nightfall were warm enough to enable this behemoth to fly toward the light and come to rest on the nearby railing of a deck. With morning’s first sunbeams just creeping over the mountains but not yet intense enough to warm flight muscles, the dobsonfly found a way to generate its own heat as a bug geek approached with a camera. Rather than a mammalian-style shiver, a burst of rapid wing-fluttering ensued. In just under two minutes, with flight muscles warmed and ready to rock, the dobsonfly escaped the probing lens of the paparazzi.

On a chilly mountain morning, watch as a creepy female dobsonfly flutters her wings to warm flight muscles in preparation for takeoff. In less than two minutes she is ready to escape the probing lens of the camera.

As you can see, female dobsonflies are magnificent, but males are really something special with their enormous sickle-shaped mandibles. Careful observations of mano-a-mano encounters between male dobsonflies reveal that their super large jaws are used in combat to dislodge competitors from substrates where potential mates might be present. These mandibles are useless in capturing prey and both male and female dobsonflies, which have powerful jaws, are not predatory as adults. As adults their diet is likely a liquid one.

Juvenile dobsonflies go by the name of hellgrammites and live a life aquatic. These fierce predators roam the interstitial spaces between stones and vegetation at the bottom of rapidly flowing streams, where they capture and dine on immature mayflies, stoneflies, and caddisflies. Experience tells me that their powerful jaws can deliver a memorable bite to unsuspecting humans attempting a capture. Hellgrammites are a key indicator of stream health and not found in polluted waters. Fish adore them and they are excellent bait. Like many aquatic insects, hellgrammites have gills lining the margins of the abdomen enabling them to extract oxygen from their watery habitat. In an unusual developmental twist, they also have spiracles, breathing ports, which allow them to obtain air on land. This adaptation is critical to their amphibious life style as they climb out of the water to build pupal chambers on land beneath stones, logs, or other moist protected structures. You may encounter adult dobsonflies in the morning near lighted buildings, as both sexes are attracted to light.  After mating, female dobsonflies deposit eggs on vegetation overhanging water. Hatchlings drop to the stream below to roam the benthos in search of prey. Larval development can take from one to three years. Over the next several weeks as you wander the banks of freshwater streams and rivers in our region, or visit structures with nighttime illumination near waterways, keep an eye open for these marvelous giants of the insect world.     

Acknowledgements

Bug of the Week thanks Nolan for providing images that were the inspiration for this episode. The wonderful publications “Behavioral Observations on the Dobsonfly, Corydalus cornutus (Megaloptera: Corydalidae) with Photographic Evidence of the Use of the Elongate Mandibles in the Male” by T. J. Simonsen, J. J. Dombroskie, and D. D. Lawrie, and “Featured Creatures, common name: eastern dobsonfly (adult), hellgrammite (larva), scientific name: Corydalus cornutus (Linnaeus) (Insecta: Megaloptera: Corydalidae: Corydalinae)” by D. Hall, and “Comparative Thermoregulation of Four Montane Butterflies of Different Mass” by Bernd Heinrich, were used as references for this episode. Many thanks to Nolan Jenkins for providing the cool image of the huge-jawed male dobsonfly.

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The last time we visited the magnificent monarch butterfly was August 27, 2018. That particular August turned out to be a rather good season for monarchs at my home in Columbia, MD. Monarch season this year got off to a pretty slow start with the first monarch arriving in the last week of July. Since then, on a daily basis, monarchs have been gliding about the flower beds, sipping nectar from the zinnias and cup plants during daylight hours. Their journey to grace my garden began months ago in early spring. In the Eastern US, these remarkable vagabonds depart their winter refuge in Mexico and continue their journey north for months, reaching milkweed patches in northern states and Southern Canada. In the Western US, a similar migration occurs as monarchs depart overwintering grounds in coastal California and head north to exploit patches of tender milkweeds as they become available in spring and summer. As summer wains days grow shorter and temperatures cool, and these travelers return to their hibernal redoubts. Eastern monarchs embark on an epic journey thousands of miles south to Oyamel fir forests in the mountains of Mexico. Western monarchs return to eucalypt and pine forests of coastal California from summering grounds in Washington, Oregon, Idaho, and several other western states. While 2018 was a rather good year for monarchs in my garden in Maryland, the outlook for migratory monarchs in Eastern and Western North America isn’t so rosy.

In a previous episode, we communed with thousands of western monarchs in Pacific Grove, CA, also known as “Butterfly Town, USA.” During the brief six years since our last visit to Pacific Grove in 2014, overwintering populations of monarchs in California nose-dived from tens of thousands to a shocking 1,914 counted in the 2020 winter census, a decline of more than 99.9% from historic levels. Eastern monarchs have fared better but still their numbers have declined dramatically to around 20% of historic high levels. Many believe it may already be too late to save the Western migratory monarchs and Eastern monarchs may not be far behind. Attempts to have monarchs declared an endangered species by the US Fish and Wildlife Service failed in December of 2020 as resources were needed to focus on “higher-priority listing actions” according to agency officials. The case for endangered species status will be revisited in upcoming years.

Scientists studying monarch butterflies believe multiple factors conspire to threaten populations of monarchs. Illegal logging of trees in the mountains of Mexico has reduced the critical overwintering habitat for monarchs. Without this refuge monarchs cannot survive winter. Scientists suggest that more severe weather events associated with climate change may also threaten monarchs. Freakish winter weather in the mountains of Mexico in 2002 killed an estimated 75% of overwintering monarchs. In the winter of 2015–2016, a late winter storm killed more than 7% of overwintering monarchs. These events translated into tens of millions fewer monarchs making their way north for the annual migration.

In the US Midwest and Pacific Northwest, record summer heat in 2012 and 2015 killed untold numbers of monarch caterpillars. Throughout the US, urban sprawl and the use of herbicides in agricultural production greatly reduce populations of milkweed plants that are vital for the survival of monarch caterpillars. Increasing levels of atmospheric carbon dioxide may change the chemical composition of milkweeds, altering levels of pharmacological chemicals that help monarch caterpillars thwart disease-causing microbes. There is also concern that planting the exotic tropical milkweed, Asclepias curassavica, may interrupt the primal migration behavior of monarchs and cause them to take up residence in areas where tropical milkweeds are planted, derailing their age-old migrations. Another study suggests that when tropical milkweed grows at high temperatures, it becomes more toxic to monarch caterpillars. As the world warms and the growing season get longer, monarchs may expand their range further northward into Canada in search of high-quality milkweeds. This may increase risks of starvation or predation as monarchs attempt an already very long and perilous journey to overwintering grounds in Mexico.  

What can be done to help save these unique and charismatic creatures? Globally, mitigating climate change, reducing unnecessary pesticide use, and conserving resources and habitats for wildlife will help. Locally, providing milkweeds for monarch caterpillars and nectar plants for adults will facilitate reproduction and survival. Regional references for milkweed plants can be found at this link https://xerces.org/milkweed and references for monarch nectar plants can be found at this link https://xerces.org/monarchs/monarch-nectar-plant-guides. Be sure to consult a reference to learn what milkweeds work well in your geographic region. Here in Maryland, species including common milkweed, Asclepias syriaca, swamp milkweed, Asclepias incarnata, and butterfly weed, Asclepias tuberosa, are good choices.

After imbibing nectar, the monarch finds just the right leaf on which to place an egg. Under the watchful gaze of a milkweed leaf beetle, a tiny monarch caterpillar consumes a leaf but soon it will grow into a behemoth capable of consuming milkweed seedpods. Within a dazzling chrysalis, a caterpillar becomes a butterfly ready to feed, fly, and spawn the next generation.

In the waning weeks of summer, go to the meadow and enjoy these beauties. Next spring plan to include milkweed and monarch nectar plants in your perennial gardens. We have a role to play in conserving these remarkable wanderers.

Acknowledgements

The excellent references, “Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk?” by Lincoln Brower and colleagues, and “Quantifying impacts of climate change on species interactions while fostering undergraduate research experiences using the Monarch (Danaus plexippus)- Milkweed (Asclepias Sp.) system” by Matthew J. Faldyn, “Monarch butterflies denied endangered species listing despite shocking decline” by Farah Eltohamy, and “ We’re losing monarchs fast—here’s why. It’s not too late to save them, but it’s a question of whether we make the effort” by Carrie Arnold, were consulted for this episode. To learn more about monarchs, their migrations and perils, and how to conserve them, please visit the following websites:

https://xerces.org/monarchs/western-monarch-conservation

https://xerces.org/monarchs/eastern-monarch-conservation

https://xerces.org/blog/monarch-numbers-from-mexico-point-to-declining-population

https://www.nationalgeographic.com/animals/article/monarch-butterflies-near-extinction

https://www.nationalgeographic.com/animals/article/monarch-butterflies-risk-extinction-climate-change

https://www.washingtonpost.com/world/the_americas/climate-change-is-playing-havoc-with-mexicos-monarch-butterfly-migration/2019/12/23/e60c1e0e-21ab-11ea-b034-de7dc2b5199b_story.html

http://www.monarchwatch.org/index.html   

http://www.eeb.cornell.edu/agrawal/2017/02/10/monarch-population-size-over-winter-2016-2017-announced/

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In last week’s episode, we met several truly remarkable caterpillars, larvae of swallowtail and brush footed butterflies, that have evolved the clever defense of looking like bird droppings to fool the searching eyes of hungry predators. This week we travel the muddy banks and floodplains of the mighty Potomac River to visit the gorgeous zebra swallowtail butterfly and its larvae that employ a survival strategy different from the bird-dropping-mimics we met last week.

Along the banks of the Potomac and other tributaries of the Chesapeake grow small forests of beautiful native pawpaw trees. A walk amongst these winsome understory trees sets one to wondering why their luxuriant green leaves go virtually unmolested by leaf-eating insects and vertebrates during the growing season. Even rapacious white-tailed deer shun these plants. Pawpaw has evolved a clever defense, a noxious group of chemicals called annonaceous acetogenins. These bioactive compounds, found in both leaves and bark, likely make them unpalatable to a diverse array of hungry herbivores. In addition to nasty metabolic effects, acetogenins are known to produce a potent emetic response in vertebrates. Ah, but herbivorous insects often discover ways to deal with defenses thrown at them by plants. In previous episodes we learned how monarch caterpillars turned the tables on milkweeds and used defensive compounds produced by milkweeds for their own defense against predators. A similar story holds for the zebra swallowtail butterfly. Sophisticated chemical analysis revealed that zebra swallowtail caterpillars and adult butterflies contained annonaceous acetogenins similar to those found in pawpaws. Scientists believe that these compounds originate in the leaves of pawpaw, are stored in the tissues of caterpillars as they eat leaves, and are passed along to the adult butterfly. The presence of acetogenins likely helps protect both the beautiful butterflies and their larvae from the beaks and teeth of hungry predators.

Along the banks of the mighty Potomac, zebra swallowtails “mudpuddle” to obtain sodium and other minerals necessary for life. Watch as the zebra probes the soil with her proboscis. Caterpillars of the zebra swallowtail are elusive. After searching hundreds of pawpaws, I finally discovered an almost fully developed larva taking a stroll along a pawpaw branch.

During the next month or so, find a moment for a walk along the Potomac or other nearby rivers where pawpaws grow. Soon the delicious fruits of the pawpaw tree will be ripe. Be sure to keep an eye open for zebra swallowtails and spend a few moments searching pawpaw leaves for magnificent zebra caterpillars.

Acknowledgements

“Chemical Defense in the Zebra Swallowtail Butterfly, Eurytides marcellus, Involving Annonaceous Acetogenins” by John M. Martin, Stephen R. Madigosky, Zhe-ming Gu, Dawei Zhou, Jinn Wu, and Jerry L. McLaughlin, and “Common name: zebra swallowtail, scientific name: Protographium marcellus (Cramer) (Insecta: Lepidoptera: Papilionidae)” by Jerry F. Butler and Donald W. Hall were consulted in preparation of this episode.

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The art of deception has evolved many times in the insect kingdom. In previous episodes we met members of the phasmatid clan from around the globe, walking sticks from the hills in Maryland, jungles of Vietnam, forests of Australia, coastal plains of Florida, and rainforests of Malaysia that did their best to resemble branches, twigs, and leaves of plants. Their clever ruse of resembling parts of plants enables otherwise tasty prey to be overlooked by the hungry eyes of visually astute predators like birds, lizards, and mammals. Similar acts of deception are seen in katydids and other insects with green colors and patterns that mimic leaves of plants.

Ah, but twigs and leaves are not nature’s only items of little or no interest to meat-eaters. Two years ago, while dining outdoors on the patio of a popular restaurant in NYC, we were bombarded with bird droppings from starlings in shade trees overhead. As diners dropped crumbs or abandoned their meals, starlings swooped down to battle over morsels on the ground and scavenge uneaten tidbits from lunch plates. While awaiting the next meal, birds returned to lofty perches and relieved themselves, thereby creating quite a mess on tables and chairs below. While watching the action and dodging birds, not once did I see a bird attempt a taste-test of droppings deposited by the rest of the flock. Forged by eons of selection, many insects have evolved a mien bearing a very close resemblance to a bird dropping. How clever is this? What self-respecting insectivorous bird eats a bird dropping, right?  

Let’s start with a bird dropping. We’ve all seen these. Next, look at the caterpillar of the red-spotted purple, a bird-dropping mimic that turns into a cool butterfly often seen on the forest floor. If you grow parsley, dill, or fennel you may have seen the black swallowtail caterpillar feasting on your herbs. Adult black swallowtails are common visitors to flower gardens. Within a silken shelter on a leaf, you’ll find another bird dropping mimic, the eastern tiger swallowtail caterpillar. Adult eastern tiger swallowtails sip nectar from butterfly weed.

A week or so ago while visiting the spectacular Cacapon State Park in Berkeley Springs, WV, my granddaughter spotted the beautiful wood-nymph, Eudryus grata. Of course, the initial response to this discovery was “don’t touch” but on closer inspection and with a little prodding, what first appeared to be a rather juicy bird dropping took flight and landed on a nearby leaf. The beautiful wood-nymph ranges from Canada to Texas, where caterpillars dine on members of the grape family. In the northern part of its range one generation occurs annually, but in Florida and southern states multiple generations occur each year.

The caterpillar of the gorgeous red-spotted purple butterfly feeds on leaves of cherry, oak, and poplar and resembles a rather large and gooey bird dropping. Larvae of several species of swallowtail butterflies mimic bird droppings in the early stages of development. Those commonly found in our area include dill and parsley munching black swallowtail caterpillars, eastern tiger swallowtail caterpillars which dine on leaves of tulip poplar, magnolia, and several other species, and pretty spicebush swallowtail caterpillars often found on sassafras as well as spice bush. Next time you see what appears to be a bird dropping resting on a leaf, take a second look and you might be treated to the discovery of one of many tiny masters of a frequently overlooked and unusual disguise.

Acknowledgements

Bug of the Week thanks Eloise for spotting the beautiful wood nymph butterfly and providing inspiration for this episode. The wonderful meadows, gardens, and forests of Cacapon State Park were the backdrop for observing several species of swallowtail butterflies. “Insect defenses” by David Evans and Justin Schmidt, and “Caterpillars of Eastern North America” by David Wagner were used as references.

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Several weeks ago, on June 21, Bug of the Week said farewell to Brood X periodical cicadas in the DMV. However, this week there is one more tale to tell about these iconic invertebrates. As interest in Brood X developed this spring, one of the most frequently asked questions was “how many cicadas will there be?” Although it was and is impossible to answer this question precisely, estimates of billions were often bantered about and those prone to hyperbole guesstimated numbers in the trillions. If that sounds like a lot of cicadas, ruminate on this for a moment. Recall that female cicadas lay eggs in the treetops and upon hatching, cicada nymphs tumble to earth and enter the soil to feed on tree roots. It is widely reported that each female cicada has the potential to lay from 400 to 600 eggs during the course of her lifetime. Suppose that only 10 billion female cicadas lived to reproduce fully and each laid a modest 400 eggs. This would translate into a several trillion cicada nymphs falling from trees in the eastern half of the United States courtesy of Brood X. Yikes!

This week an eminent member of the press corps inquired about potential showers of cicadas raining down on citizens in the DMV as billions of cicada nymphs hatched from eggs imbedded in small branches and tumbled to the earth below. The ancillary question was, of course, would people notice the cicada shower? Recalling a recent dewy shower of cicada pee while studying cicada behavior, I anticipated a repeat performance while working under trees wearing scores of flagging branches and hundreds of healthy branches bearing thousands of cicada egg nests. To date I have not experienced a deluge of cicada nymphs dropping from trees, despite the fact that egg-hatch is in full swing as of this writing.

During most of their embryonic development, little detail can be seen of the cicada nymph within the egg. Within days of hatching however, eyes become visible in hues of red or brown. Using muscular contractions, cicada nymphs slither from the confines of their eggshell, ready to skedaddle in a matter of minutes. After tumbling from the treetop to earth, they join thousands of brood mates entering the soil in search of plant roots that will sustain them for the next 17 years.

Part of the explanation why I and most other people will not notice periodical cicadas as they hatch and fall to earth is the minute size of cicada nymphs. At only a couple millimeters in length they are very hard to spot. Their small body mass may allow breezes to carry them beyond the dripline of trees from which they hatched. Although siblings from a single egg nest hatch somewhat synchronously, each cicada takes a few minutes to escape from an egg, thus causing hatching to be dispersed in time. Remember too that egg laying was distributed over several weeks in May and June. This further spreads out the rainfall of hatchlings in time. As evidenced by the massive numbers of trees with flagging branches, whether or not you encounter a shower of cicadas falling from trees, rest assured that barring some unforeseen catastrophe Brood X will return in force in 2038 here in the DMV. 

Acknowledgements

Bug of the Week thanks Paula Shrewsbury for contributing images and commentary for this week’s episode. We thank the writers of the Washington Post for providing inspiration for this episode and for their enthusiastic, continuing in-depth coverage of Brood X. Much of the background information for this episode and others was taken from “The ecology, behavior and evolution of periodical cicadas” by K. S. Williams and C. Simon, and references therein.

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The DMV abounds with some of the best nature centers in the country. Two of my favorites are Woodend Sanctuary, nestled inside the Beltway in Chevy Chase, Maryland and home of the Audubon Naturalist Society, and the Howard Conservancy, a 232-acre wildlife sanctuary in Woodstock, Maryland. Summer is always an exciting time to take a suburban safari at these refuges when some of Mother Nature’s wildest flowers are at their best. On a recent trip to the Howard Conservancy, large patches of Heliopsis, a.k.a. false sunflower and oxeye, were in dazzling full bloom. Oxeyes are full bodied members of the aster clan and our native species are dynamite attractors for many interesting insects.

While immersed among some oxeyes, I was surprised to find hordes of gorgeous seed bugs busily sucking nutrients from the developing flowers and engaging in their buggy mating rituals amongst the blooms. These little beauties are close relatives of other true bugs like the milkweed bugs and scentless plant bugs we’ve met in previous episodes. In fact, early records often confused this species with small milkweed bugs and recorded it as a denizen of milkweed. Careful observations by one Reverend James M. Sullivan of St. Louis, Missouri, helped clarify the true pattern of food choice of false milkweed bugs. However, the name false milkweed bug is a bit of a misnomer, as these little rascals actually are connoisseurs of members of the aster family.

Heliopsis is a great plant to spot false milkweed bugs. Watch as the bug on the left nonchalantly grooms its antennae while its mate taps its left hind leg somewhat impatiently while dining on a floret. Bugs are pretty entertaining.

After choosing a handsome mate and consummating the relationship, the female false milkweed bug lays eggs in batches of 15 to 50. Eggs hatch and bright red nymphs use their elongated sucking mouthparts to sip fluids from the plant. Adults can live two months, and along with their nymphs these beauties can be seen on oxeye from June through August in many parts of the country. Bug of the Week recommends a trip to the meadows and gardens at Woodend Sanctuary and the Howard Conservancy to glimpse members of the aster clan. If you encounter glorious oxeyes, take a few moments to hunt for false milkweed bugs.

Acknowledgements

We thank Woodend Sanctuary and Howard Conservancy for providing inspiration for this episode. The interesting article, “On the Biology and Food Plants of Lygaeus turcicus (Fabr.) (Hemiptera: Lygaeidae)“ by James A. Slater, was used to prepare this episode.

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