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Last week weather radar stations reported unusual low altitude clutter over several locations in the Mid-Atlantic region. News outlets including the Washington Post proclaimed that “So many spotted lanternflies are out right now, you can see it on radar.” To catch up with this story a bit, this week we will update parts of an episode first published in September 2020. 

Lanternfly adults and their youngsters, called nymphs, remove large quantities of phloem sap from woody plants as they feed. The excess is excreted from their rear end in copious amounts as a sugary waste product called honeydew. More than 100 plant taxa of woody and herbaceous plants serve as hosts for spotted lanternflies. Spotted lanternflies can be severe pests of fruit and shade trees, grapes, and hops. Massive infestations in vineyards have withstood repeated applications of insecticides and still caused the demise of entire vineyards. In home landscapes, hundreds of these rascals have been observed feeding on a single plant, where they rain scads of honeydew onto vegetation and the earth below. As with honeydew produced by other phloem feeders such as soft scales and aphids, the honeydew excreted by lanternflies fouls foliage, fruit, and underlying plants, and serves as a substrate for the growth of a fungus known as sooty mold. Honeydew makes leaves sticky and fruit unmarketable, and sooty mold further disfigures leaves and fruit and may impair photosynthesis. This presents a huge economic problem for growers of apples, cherries, peaches, and grapes. Sweet honeydew and its fermentation products also attract a variety of stinging insects like yellowjackets and paper wasps.

How far do spotted lanternflies move? The immature stages called nymphs don’t move all that far. A clever study conducted by Kelli Hoover and her colleagues at Penn State found that some spotted lanternfly nymphs travel as much as 213 feet in their quest to find a suitable host, but only about half traveled 56 feet. However, studies by scientists in Pennsylvania reveal some of the secrets to the longer distance autumnal movements of adult spotted lanternflies. Thomas Baker and his colleagues at Penn State discovered that slim fancy flyers are primarily unmated females capable of flights ranging from roughly 30 to 150 feet. Their spontaneous flights are believed to be quests to find suitable host plants that will supply sufficient nutrients for them to fatten up and deposit a complete complement of eggs before cold weather puts an end to their mischief. The Penn State team also assessed the flight worthiness of plump yellow-bellied lanternflies commonly found on hosts like tree of heaven. A vast majority of these heavy females had successfully mated but their ability to fly was weak and limited to only about 12 feet when launched into the air.

To see spotted lanternflies in flight and see why they are showing up on radar, please click this here (Courtesy of Cornell Integrated Pest Management). Radar sightings of insects are not all that unusual. Four years ago in 2021, during the emergence of Brood X periodical cicadas, cicadas in flight were captured on radar in the DMV.  Swarms of devastating locusts in Africa and Asia are often tracked on radar. 

While spontaneous autumnal flights have been witnessed on a regular basis, these relatively short distance flights of hundreds of feet likely account for only a minor component of the spotted lanternflies’ prodigious spread in the eastern United States. From their initial discovery point in Berks County in 2014, it has moved more than 650 miles and established populations of spotted lanternflies have been discovered in Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Massachusetts, Michigan, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, West Virginia and, of course, the District of Columbia.

Spotted lanternflies are on the wing to find new host plants, bringing them in contact with the human-built world where they will wander buildings and benches in search of food. Many will perish of starvation or dehydration on sidewalks and in parking lots. Others will be squashed beneath feet and automobile tires. Some may visit shoppers and diners briefly before flying off, while others will be snared and killed by urban spiders. Before you leave a parking area infested with lanternflies, inspect your car to make sure these clever vagabonds are not hitching a ride with you.

According to entomologist Julie Urban, the most likely explanation for these long-distance peregrinations lies in human-assisted transport of lanternfly eggs. It is believed that spotted lanternflies arrived in Pennsylvania around 2012 from Asia in a shipment of stone products bearing lanternfly eggs, a trip of some 7,000 miles. Unlike many herbivorous insects that lay eggs on food plants for their young, spotted lanternfly mothers often deposit egg masses on human-made non-host objects including stones, cinder blocks, lawn furniture, pallets, and vehicles, in addition to trees. These rather nondescript egg masses are easily overlooked on natural and human-made items and transported inadvertently by road or rail, moving this invasive pest significant distances and accounting for a major component of the long-range spread of spotted lanternflies.

So, how far will spotted lanternfly spread in the US? Based on climatic data from the US and Asia, scientists suggest that much of the eastern United States and portions of California, Oregon, and Washington State have climates suitable for the survival of spotted lanternfly. This is not good news for the magnificent and economically important grape growing regions in our western states. Will spotted lanternflies soon be coming to your neighborhood? Time will tell, but as I have often heard, you can usually bet on the bug.

To learn more about spotted lanternfly please visit the brilliant, fact-packed Penn State Cooperative Extension Website at this link: https://extension.psu.edu/spotted-lanternfly

Acknowledgements

Bug of the Week thanks Dr. Shrewsbury for spotting and wrangling spotted lanternflies for this episode. Thanks to Jessica Kronzer for providing inspiration for this story. We acknowledge the great work of scientists contributing to our knowledge of this pest, with particular thanks to authors of articles used as references, including Flight “Dispersal Capabilities of Female Spotted Lanternflies (Lycorma delicatula) Related to Size and Mating Status” by Michael S. Wolfin, Muhammad Binyameen, Yanchen Wang, Julie M. Urban, Dana C. Roberts, and Thomas Charles Baker,  “Worldwide Feeding Host Plants of Spotted Lanternfly, With Significant Additions from North America” by Lawrence Barringer and Claire M. Ciafré, “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, and “The Establishment Risk of Lycorma delicatula (Hemiptera: Fulgoridae) in the United States and Globally” by Tewodros T. Wakie, Lisa G. Neven, Wee L. Yee, and  Zhaozhi Lu. 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 and to the Entomological Society of America for providing the map of the potential distribution of spotted lanternfly in the US.

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We first visited the Jorō spider in March of 2022 and wondered if there was any chance that it would make its way to the DMV. Little did we know that in September of 2022 two observations of Jorō spiders in eastern Howard County would be reported to iNaturalist. Three years and some 40 sightings later, we know that Jorō spiders are happy and doing just fine in several Howard County locations, including Ilchester, West Elkridge, and Elkridge. A week or so ago, a team of scientists from the University embarked on a mission to access the spread of an awful disease known as beech leaf disease (BLD) that is killing our ultra valuable beech trees in the DMV and eastern US. Their sortie took them to a state forest in eastern Howard County near Elkridge. While searching for BLD, they discovered a remarkable colony of Jorō spiders thriving amongst the beech trees. The recent discoveries of Jorō spiders thriving in Maryland confirms a prognostication made by scientists Davis and Frick that physiological plasticity might allow Jorō spiders to escape the relative warmth of areas it has invaded in the southeastern US and expand its range northward along the eastern seaboard. With Jorō spiders merely 20 minutes away from home, how could one resist the opportunity to visit these amazing predators? The tales of how Jorō spiders and their cousin, the golden silk spider, arrived in the US can be found in previous episodes posted in 2022 and 2024.

However, to reduce some angst associated with a large non-native spider establishing in the DMV, here are a few things you should know. These facts were first presented in a past episode. The bite of the “venomous” Jorō spider will be terrible and painful, right? Nah, according to expert Rick Hoebeke, the risks to humans and pets are small due to the puny size of Jorō’s fangs, which are unlikely to pierce our skin. As you will see in this week’s video, I have visited Jorō and found the large females to be completely non-aggressive.

A secondary forest in eastern Howard County has been colonized by Jorō spiders. Their haphazard webs a littered with the remains of former victims, leaves, and shed exoskeletons. The much larger female Jorō spider dwarfs her mate, positioned just above her. See if you can spot a strand of silk produced by the spinnerets on the underside of her abdomen near the red mound. Relative to my hand, you can see how large and how docile Jorō is. We will wait and see what the Jorō spider means to ecosystems here in the DMV. Maybe they will help other spiders put a beat-down on invasive pests like stink bugs and spotted lanternflies. Video by Mike Raupp and Paula Shrewsbury

These spiders are passive hunters that build enormous webs, larger than a meter in diameter, to capture prey snared in the silk. For arachnophobes these may be scary, but for arachnophiles these are beautiful spiders which may provide important ecosystem services including biological control of crop pests such as brown marmorated stink bugs or spotted lanternflies, with which they have an ancient association in their native range in Asia. Jorō spiders may be likened to Hannibal Lecter “having an old friend over for dinner” when they reunite with the stink bug or lanternfly here in the US.

Large spiders like these may also become juicy prey items for feathered and non-feathered reptiles. As with all non-native species that arrive in our land, it is difficult to predict what impact they will have on our ecosystems but experts suggest that beyond their somewhat scary mien, they may give our indigenous large orb weavers like the black and yellow garden spider, marbled orb weaver, and spotted orb weaver a run for their money. In locations in other parts of the world where Jorō is established, it often becomes the most abundant and dominant orb weaver. What will it mean for our resident spiders and their ecosystems? Only time will tell.

One final tidbit about Jorō comes from Japanese folklore. Jorō is a shapeshifter known as Jorō-gumo.  Jorō-gumo turns into a beautiful woman, seduces men, binds them with silk, and devours them. Yikes! Sounds like a bad date to me.

Acknowledgements

Bug of the Week thanks Rick Hoebeke for identifying Jorō as it arrived in the US and for providing insights into the ways of these large, beautiful spiders. We also thank David Coyle and Bob Bellinger for sharing great images and knowledge of Jorō. Fascinating studies entitled “Veni, vidi, vici? Future spread and ecological impacts of a rapidly expanding invasive predator population” by David R. Nelsen, Aaron G. Corbit, Angela Chuang, John F. Deitsch, Michael I. Sitvarin and David R. Coyle,  “Physiological evaluation of newly invasive Jorō spiders (Trichonephila clavata) in the southeastern USA compared to their naturalized cousin, Trichonephila clavipes” by Andrew K. Davis and Benjamin L. Frick, “Nephila clavata L Koch, the Joro Spider of East Asia, newly recorded from North America (Araneae: Nephilidae)” by E. Richard Hoebeke, Wesley Huffmaster, and Byron J Freeman, and “The Life Cycle, Habitat and Variation in Selected Web Parameters in the Spider, Nephila clavipes Koch (Araneidae)” by Clovis W. Moore ND provided the inspiration for this story and details surrounding the stars of this episode. We thank Dr. Dave Clement, Miri Talabac, and Maddie Potter for hooking us up with the colony of Jorō spiders.  

To see other large orb weavers and to differentiate them from the Jorō spider, please click on this link: https://resources.ipmcenters.org/view/resource.cfm?rid=27877

To hear more about the Jorō spider and calm your fears about Jorō, please click on this link to Jorō guru David Coyle’s take on this spider: https://youtu.be/zhO_bwwg-E4?si=nhd9au-t-HRCmw6b

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Delightful meteorological events mark the transition from summer to autumn in the Mid-Atlantic region.  Fog created by small water droplets suspended just above the ground condense on strands of spider silk as moist air cools. Morning light reveals numerically astounding and perhaps somewhat disturbing presence of spiders whose webs usually go unnoticed in the landscape. On one such misty morning my neighbor’s pachysandra and boxwood plants were festooned with more than a dozen gossamer webs. The webs were not the typical vertical orbs of concentric circle supported by radial strands like those of black and yellow garden spiders, spotted orb weavers, or marbled orb weavers we met in previous episodes. Rather, these webs consisted of horizontal 8 by 12 inch sheets each bearing a small remarkably round funnel at one end. The proprietor of the web, a handsome dappled brown and tan spider, often perched near the mouth of the funnel. My attempts to photograph these beauties were regularly thwarted by the agile spider able to disappear down the funnel in the blink of an eye.

When threatened by a predator or bug geek, the funnel weaving spider can disappear down its funnel in hole in the blink of an eye.

Funnel weaving spiders, a.k.a. grass spiders, are often confused by name with their more famous and perfidious relatives the funnel web spiders.  The bite of the Australian funnel web spider is potentially deadly to humans whereas the bite of Agelenopsis pennsylvanica, the Pennsylvania Grass Spider, is deadly only to their tiny insect prey. It is difficult to image how a human could be bitten by these shy spiders. Despite the ability of the web to capture droplets of fog, silken strands of funnel weaving spiders cannot snare small insects. They lack the sticky polymer found on the bug-catching strands of spider webs like those large orb weavers. Instead of trapping prey, funnel weaving spiders rely on a lightning fast attack and fang-strike to immobilize hapless victims that blunder onto their web. Like many other arthropods including the praying mantis and black widow spider, the female Pennsylvania Grass Spider engages in sexual cannibalism. The she-spider often eats her mate. Why does she do this? Is she grumpy or her suitor’s performance fail to meet expectations? In a clever study scientists discovered that hungry and particularly aggressive females tended to be cannibals. More importantly, the cannibalistic females produced heavier egg cases and the eggs within each case experienced increased success of hatching. If you are female Pennsylvania Grass Spider, it pays to eat your mate. So, for humans on foggy autumn morning enjoy the handiwork of funnel weaving spiders, but if you are a male funnel weaving spider think twice about who you date.    

Acknowledgements

Bug of the Week thanks non-cannibalistic Dr. Shrewsbury for photographing and wrangling spiders for this week’s episode and Dr. Shultz for providing the identification. Thanks to Kaitlyn McGrath inquiry about mysterious webs which provided inspiration for this episode. Two excellent references “Some Commonly Encountered Pennsylvania Spiders” by Steve Jacobs and “Sexual cannibalism is associated with female behavioural type, hunger state and increased hatching success” by Aric Berning and colleagues were consulted.

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What’s not to like about lady beetles, right? Cute, sometimes brightly colored beetles helping to rid our gardens and landscapes of pests like crape myrtle bark scales and aphids. Well, sometimes they do invade our homes. But like many large families, part of the clan sometimes goes astray and lady beetles in the genus Epilachna evolved to eat plants rather than other insects.

The aboriginal home of the Mexican bean beetle is the high southern plateau of Mexico where many members of the bean plant family grow. As beans became widely cultivated in the United States, the Mexican bean beetle crossed the border and spread throughout the eastern half of the US where moist conditions and many types of cultivated beans favor its survival. In some years, Mexican bean beetles are relatively scarce due to depredations of a small parasitic wasp, Pediobius faveolatus, released decades ago in the mid-Atlantic region. However, in a local community garden, this year’s wet spring and warm summer seem to have provided the perfect growing conditions for the bean beetle.

A recent visit to the community garden revealed all sorts of beans in sad shape. This saga began back in spring when female Mexican bean beetles deposited scads of bright yellow eggs on undersides of bean leaves. From the eggs hatched spiny bright yellow larvae that scraped the epidermis from the leaf surface creating damage called etching. As larvae grew, their strong jaws chewed holes in the leaves. When larval development was completed, they formed pupae which dangled beneath bean leaves. From these pupae hungry adult beetles emerged and continued the impressive defoliation of the beans. One fool proof way to help reduce populations of beetles is to remove adults, larvae, and eggs from the beans when you find them. 

As I meandered through the garden plots, almost every leaf of snap and lima beans was skeletonized by the feeding of the larvae and adults of this mini-jawed monster. Bristly, bright yellow larvae fed alone or in groups of 2 or 3. Orange and yellow adults with black spots scraped and munched the green tissue between the tougher veins of bean leaves. This nutritious food is converted into eggs and each female can produce as many as 600 eggs during the course of her lifetime. Laid by dozens, these bright yellow eggs hatch in about a week. Larvae complete development and form pupae, which hang suspended from the leaves of bean plants. As summer wanes, adult beetles seek shelter in decaying vegetation or leaf litter to survive the chill of winter. In spring, adults emerge from their refuge and move back to the bean fields to resume feeding and producing pestiferous spawn.

One way to reduce problems caused by these hungry bean-eaters is to remove plant refuse from the garden plot at the end of the growing season. Refuse relocation forces overwintering beetles to take a longer and more perilous journey to the garden from hibernal refuges. Some gardeners use floating row covers with a fine mesh to prevent beetles from reaching the bean leaves. These should be put in place early and kept in good repair. Another strategy to confound this pest is to plant a small “trap crop” of a favored food like snap beans in the garden early in the season. This early plot will attract and collect overwintering beetles as they emerge from their refuges. Once the beetles have moved in, the trap is set, and by annihilating the trap crop loaded with beetles, the number of beetles remaining to attack beans planted later in the growing season will be reduced.

 

Another method of control is a bit more direct and involves crushing eggs, larvae, and adults on the plants. Seems foolproof but be forewarned that fingers may turn orange after encountering defensive secretions produced by the beetles. And if you go the crushing route, please avoid the urge to lick your fingers, as the defensive secretions produced by the larvae and adults are a witches’ brew of noxious alkaloidal compounds that ward-off would-be predators. If you want to go the biological control route, the parasitic wasp Pediobius faveolatus may be available from commercial suppliers and released in your garden but be sure to follow directions as timing is critical for this method of intervention. While it may be a little late to save the beans this season, make a note of the health of your beans this year and consider your options for next year. Remember, beans are good.                    

References

 Information used in preparing this Bug of the Week came from the marvelous article “The chemistry of phyletic dominance” by J. Meinwald and T. Eisner. Bug of the Week thanks community gardener Barbara for demonstrating the value of row covers.

More information on Mexican bean beetle and its management can be found at the following website: https://extension.umd.edu/resource/mexican-bean-beetle-vegetables/

 

 

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There is no mistaking this caterpillar on a boxwood. This is the larva of the box tree moth. Paula Shrewsbury image

From the time of our earliest European colonists, boxwoods have been important components of ornamental landscapes. Boxwoods grace iconic landscapes in the DMV including George Washington’s home at Mount Vernon, the “Box Walk” at  Dumbarton Oaks,  the National Boxwood Collection at the United States National Arboretum, as well as hundreds of public and private gardens and landscapes in our region. However, boxwoods are one of the most problem-prone plants in our landscapes. Already beset by exotic pests including leafminers, spider mites, and pathogens such as boxwood blight, boxwoods in the DMV and throughout our country now face a new, lethal non-native invader, the box tree moth.  Like many of our new invaders box tree moth is native to Asia in China, Japan, and Korea. Probably due to the movement of ornamental plants, it entered Europe and was first discovered in Germany in 2007. It now occupies more than 30 Eurasian countries. It jumped across the Atlantic to Canada where it was detected in 2018 and arrived in the United States with shipments of nursery plants from Canada in 2020 and 2021. Prior to July, 2025 it spread to Delaware, Massachusetts, Michigan, Ohio, Pennsylvania, West Virginia, and New York. Yes, the DMV was surrounded and sure enough, it was detected in Clarke and Loudoun Counties in Virginia and three locations in Washington County in Maryland during the latter half of July and early August.

Iconic boxwoods are one of the most widely planted shrubs throughout the country and here in the DMV. Beset by pests like leafminers, spider mites, and boxwood blight, they now have a devastating new enemy, the box tree moth. Caterpillars of box tree moth defoliated these once handsome boxwoods. The shrubs will be destroyed in hopes of slowing the spread of the moth. Watch as hordes of caterpillars consume foliage until only midveins and silken webs laced with nasty frass remain. In addition to destroying the boxwoods, these miserable leaf-munchers will sometimes eat each other. If your boxwood looks like this, and you see these, please contact your state department of agriculture or university extension service.

What’s the worry? If undetected, an infested boxwood can support a rapidly expanding population of leaf-eating caterpillars capable of completely defoliating large boxwoods. In addition, they create large silken webs littered with frass that accumulates on plants and on surfaces below.

How is this possible? Adult boxwood tree moths lay multiple clutches of 5 to 20 eggs. Larvae that hatch from the eggs are voracious herbivores that first remove green leaf tissue as youngsters and later consume entire leaves. And if this was not bad enough, after leaves are consumed, they feed on woody tissues thereby girdling stems and branches, hastening boxwood death. One generation of this carnage is bad enough, but box tree moth will have many generations in the DMV. In other locations, as many as 4 or 5  generations may occur annually depending on temperature regimes.

What should you look for? Discoloration, a change in the color of leaves from vibrant green to dull brown or gray and defoliation, the loss of parts or entire leaves are often the first and most easily recognizable clues that your boxwoods may be infested with box tree moth. Since no native moth or butterfly has caterpillars that readily eat leaves of boxwoods, the presence of large numbers of strikingly colored black, green, and yellow striped caterpillars with black heads is a dead giveaway for the presence of box tree moths. However, several other arthropod pests and diseases can cause discoloration, defoliation, and dieback on boxwoods. Fortunately, Joe Boggs of The Ohio State University has complied a wonderful pictorial guide to diagnosing boxwood pests and diseases including symptoms and signs of box tree moth.

Defoliated leaves covered with silk and hordes of caterpillars decked out in stripes and spots of green, yellow, white, and black with shiny jet-black heads mark an infestation of box tree moth caterpillars. Paula Shrewsbury image

What should you do if you find box tree moth? The Maryland Department of Agriculture is presently engaged in a program to limit the spread of box tree moth. If you suspect you have this pest, the Department of Agriculture recommends the following:

·         If you suspect your boxwoods may be infested with the box tree moth, please contact via email the Plant Protection and Weed Management program at [email protected]. Please attach a picture in your email.

·         Allow Maryland or Federal agricultural officials to inspect your boxwood plants and place detection traps.

·         Any infested material should be doubled bagged in plastic bags and placed in the trash.

·         Nursery owners should monitor their boxwoods and implement safeguards to limit pest risk. All licensed nurseries should report BTM detections to the Maryland Dept of Agriculture Nursery Inspection Program or reach out to their nursery inspector.

Moving forward, what might the future hold for the box tree moth and us? Unfortunately, like emerald ash borers, brown marmorated stink bugs, spotted lanternflies and many other non-native pests of our landscape plants, the box tree moth is likely here to stay. However, Mother Nature in cooperation with humans often has a solution for these invaders. Indigenous natural enemies, predators, parasitoids, and pathogens often rally and put a beat-down on these non-native pests. Clever scientists search and discover natural enemies from afar and after exhaustive evaluation release them to reduce populations of invaders here in the US. Researchers develop chemicals to detect, attract, trap, and kill non-native pests. Even today several insecticides are available to kill caterpillars. Some of these contain active ingredients like Bacillus thuringiensis, a.k.a. BT, and spinosad which are dynamite for controlling caterpillars but safe enough to be used in organic food production.  If you want to learn more about insecticides that can be used to manage box tree moth caterpillars, click on this link. With diligence, ingenuity, good science, and help from Mother Nature, we will find ways to manage this new  noxious invader.  

Box tree moth caterpillars can destroy an established stand of boxwoods like this one in a matter of weeks. Joe Boggs, OSU.

References and acknowledgements

“The fast invasion of Europe by the box tree moth: an additional example coupling multiple introduction events, bridgehead effects and admixture events” by Audrey Bras, Eric Lombaert, Marc Kenis, Hongmei Li, Alexis Bernard, Jérôme Rousselet, Alain Roques, and Marie‑Anne Auger‑Rozenberg was used as a reference for this episode. We thank Joe Boggs for generously allowing us to use his wonderful images of box tree moth. The inspiration for this episode came from Phyllis and Rod who allowed us to photograph their boxwoods and caterpillars.  Please visit Box Tree Moth by Madeline Potter to learn more about this pest and explore links to additional information.

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Five years ago in an episode entitled “Missing bugs of the week: Swallowtail butterflies, Papilionidae” we explored some of the reasons pollinators in general and butterflies in particular are imperiled in the DMV and around the world. Last month a concerned nature enthusiast remarked “normally by this time of the year our meadow would be full of butterflies… even a monarch or two…. This year there’s virtually none and I hear it’s that way throughout the county.” In a sample size of one, in my own flower garden in Columbia, MD, thus far this season it has been a rotten one for large butterflies like swallowtails and monarchs that usually are plentiful by now.  My barometer for gauging butterfly abundance is a large native composite known as cup plant (Silphium perfoliatum). In years past during the last weeks of July and first weeks of August, I have seen more than a dozen swallowtails simultaneously enjoying nectar treats on my cup plant. To date only a single tiger swallowtail has visited my cup plant. How disappointing is that?  

Over the last few weeks, folks expressed concern over the absence of swallowtail butterflies in their gardens and meadows. I’ve had the same impression. This video from 2019 shows dozens of tiger swallowtails visiting my cup plant in late July. Fast forward to the same time this year when only a single tiger swallowtail has stopped by. Is this just annual variation in weather conditions or signs of larger issues related to climate change, development, and other sources of butterfly decline? Maybe missing butterflies is just a local suburban thing. Earlier this year on the banks of the Potomac, zebra swallowtails, tiger swallowtails, and other swallowtail species were common gathering minerals from the mud. And in my gardens skippers and cabbage butterflies showed up in force right on time. I’m not really sure what’s up with the swallowtails but I hope a second generation of swallowtails and maybe some monarchs make an appearance soon.

How are butterflies fairing around the country? A recent article in the Proceedings of the National Academy of Sciences  provides some clues as to why butterflies and other pollinators are becoming harder to see and why they may be declining in the United States and Canada. Tara Cornelisse and 14 colleagues found that roughly 26% of vertebrate and invertebrate pollinators are at risk of extinction in North America north of Mexico. When it comes to butterflies, of the 632 butterfly species studied, almost 20% are at risk of extinction. Of these approximately 8% of charismatic swallowtails are at risk. Yikes!

What are the underlying ecological threats to pollinators in general and butterflies specifically? We have known for decades that changes in land use patterns associated with urbanization around the world are responsible for dramatic losses of several insect species, including butterflies. In addition to urban development, the study by Cornelisse et al. ranked climate change, invasive species, changes in the natural patterns of water movement and storage, and changes in wildfire regimes as key risk factors for butterflies and moths. On a national level pollution also imperiled all pollinators in several eastern states.   

Findings of this study send a warning regarding the overall fate of pollinators in our rapidly changing world. However, declines in the abundance of butterflies from one year to the next are often linked to more immediate ecological events such as annual variation in weather. Elevated temperatures are known to reduce the survival of caterpillars. Drought is known to reduce the abundance and nutritional quality of some plants. One butterfly expert suggested that last summer’s extended heat and drought may have negatively affected the survival of butterfly larvae, thereby reducing the populations of butterflies in 2025. Perhaps, our unusually soggy spring weather favored pathogens lethal to butterfly larvae or pupae.

Should we fear that the apparent scarcity of swallowtails in 2025 in my garden in Columbia portends a pending butterfly apocalypse? Maybe not. Beyond swallowtails, other species of butterflies like silver spotted skippers and their kin arrived in my garden right on schedule in fine numbers, as did cabbage butterflies. Recent adventures along the C & O Canal this spring and summer revealed several species of butterflies including tiger and zebra swallowtails in good numbers. Rick Borchelt’s butterfly surveys in Allegany and Kent Counties in Maryland revealed solid numbers of dozens of butterfly species. But as I finish writing this episode and look out the window to the cup plant, swallowtails are still absent. However, hope springs eternal in the hearts of bug geeks and maybe an upcoming brood of swallowtails and some late-to-arrive monarchs will stop by garden my before the summer ends.

Acknowledgements

Bug of the Week thanks Paul Bade for his interest in swallowtails that provided the inspiration for this episode. Science writer, butterfly guru, and keeper of the LepLog Rick Borchelt provided great insights and observations of butterflies throughout the region. Many thanks to colleagues in the Department of Entomology, especially Karin Burghardt and Leo Shapiro for providing references and helping clarify several points discussed in this episode. The following fascinating papers were consulted: “Live fast, die young? Day- and night-warming affect the growth, survivorship, and behavior of caterpillars in the field” by Louie H. Yang, Elizabeth G. Postema, Heran Arefaine, Fernanda Y. Cohoon, Emma A. Deen, Yvonne L. Durand, Gwendolyn I. Erdosh, Hailey Ma, Courtney N. Mausling, Sarah Solís, and Madeline R. Wilson,   “Western Monarch Population Plummets: Status, Probable Causes, and Recommended Conservation Actions” by Emma M. Pelton, Cheryl B. Schultz, Sarina J. Jepsen, Scott Hoffman Black and Elizabeth E. Crone; “Multiscale seasonal factors drive the size of winter monarch colonies” by Sarah P. Saunders, Leslie Ries, Naresh Neupane, M. Isabel Ramírez, Eligio García-Serrano, Eduardo Rendón-Salinas, and Elise F. Zipkina; “Declines and Resilience of Communities of Leaf Chewing Insects on Missouri Oaks Following Spring Frost and Summer Drought” by Robert J. Marquis, John T. Lill, Rebecca E. Forkner, Josiane Le Corff, John M. Landosky and James B. Whitfield; and “Elevated extinction risk in over one-fifth of native North American pollinators” by Tara Cornelisse, David W. Inouye, Rebecca E. Irwin, Sarina Jepsen, Jonathan R. Mawdsley, Margaret Ormes, Jaret Daniels, Diane M. Debinski, Terry Griswold, John Klymko , Michael C. Orr, Leif Richardson, Nicole Sears, Dale Schweitzer, and Bruce E. Young.

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One of my favorite mythological tales is that of King Midas, the ruler of Phrygia who wished for and was granted the power to turn everything he touched into gold. Apparently, this was his undoing as he starved to death when the food he touched turned into inedible gold – poor guy. Last week my nature- loving neighbor shared a wonderful video of majestic mydas flies cavorting around the stump of an ancient pin oak tree that once graced her yard. It seems this stump serves as a perennial home for her mydas flies. Each summer they provide entertaining performances as males battle each other and find romance with the females which, in turn, search for places to deposit their spawn in just the right spot in the decaying stump. Female mydas flies deposit eggs in rotting wood where their predaceous larvae dine on other soft bodied insects, including the grubs of scarab beetles, kin of the ones we met in previous episodes such as “Hercules Beetles.”

The star of this episode, Mydas clavatus, the clubbed mydas fly, named for its clubbed antennae, is a member of a relatively small family of very large flies whose biology remains somewhat unknown. Mydas clavatus is among the largest of all North American flies, with a body length often more than an inch. It is believed that their black–velvet coloration presents the visage of a large stinging wasp. This confers protection from enlightened predators that have learned not to mess with painful, black, stinging insects. One report holds that they also have a behavioral mimicry in which they curl their abdomen and jab at an aggressor in a mock stinging charade aimed to fool potential predators.

Decaying stumps like this one serve as a home for scarab grubs, a critical food source for mydas fly larvae. Watch as a mydas fly searches the base of the stump. Maybe it’s a female looking for just the right spot to deposit her eggs. Nearby on leaves of a holly a mydas fly does a little fly dance with its forelegs.  And on a lilac near the stump another mydas fly shows no fear of a bug geek with a camera. Video credits to Pam Gealy and Michael Raupp

Adult flies have been observed dining on the nectar and pollen of flowers of Spiraea alba, Pycnanthemum virginianum, Asclepias syriaca, A. verticillata, Monarda punctata, Teucrium canadense, Verbena hastata and Saponana officinali. In years past, they frequented by garden, attracted perhaps by the abundance of butterfly weed in my flower bed which served as a beacon for this unusual visitor.

Adult mydas flies are rather tranquil and allow bug geeks to take pictures before flying away for some unknown fly business. Unfortunately for me, the mydas fly that have visited my garden for photo ops lacked the Midas touch and the holly and pumpkin on which it perched failed to turn to gold. Still, seeing these unusual creatures always provides a golden moment for a bug geek.

References

Bug of the Week thanks Pam Gealey for sharing videos and images of her majestic mydas flies that inspired with episode. Dr. Shrewsbury captured images of the mydas fly. The delightful account “Adult female Mydas clavatus (Diptera: Mydidae) feeding on flowers in Wisconsin” by Andrew H. Williams and the interesting web page “Mydas fly” by Jeffrey K. Barnes were used as references.

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In previous episodes we visited sensational Asian giant hornets, a.k.a. murder hornets, and some of their look-alikes including European hornets and cicada killer wasps. Last week I received an inquiry about male cicada killers. A curious homeowner wondered if they were harmful to humans. This week we revisit an episode from a few years ago to learn about these amazing aerial acrobats. Sit back and relax, male cicada killers are harmless to humans but female cicada killers are lethal to annual cicadas. Female cicada killers kill cicadas as a food source for their young. During the daytime, female cicada killers hunt prey in the treetops where annual cicadas are found. Once captured and paralyzed, cicadas are interred in subterranean crypts. To see how female cicada killers roll, please check out this episode of Bug of the Week, “Cicadas beware, the ladies are in town: Female cicada killer, Sphecius speciosus”.

Although they appear fierce and perhaps even dangerous, male cicada killers pose no threat to humans or pets. Only females have a stinger, and try as he might, the male’s jaws and genitalia failed to puncture my skin. However, I have heard tales of females delivering a memorable defensive sting when inadvertently stepped on or trapped under knee or hand. Video credit: Paula Shrewsbury, UMD

But in advance of the appearance of the ladies, two male cicada killers established territories about twenty feet apart in my flower bed. So began a fierce competition for dominance of space and, I suppose, eventual access to the babes soon to emerge from the earth. Each morning shortly after sunrise as the morning sun warms the land, two feisty males arrive at their respective perches, one on a short yew bush and the other on the nozzle of my garden hose. As you will see in the video, they are on high alert, frequently leaving their perch for a short flight. Not quite understanding the thinking of the wasp mind, I imagine these forays are designed to provoke a battle with the other hopeful suitor. Occasionally, these sorties extend far enough from the perch that one male will enter the territory of the other. This results in a remarkable battle complete with frenetic buzzing and males interlocked in flight. It appears much biting and kicking goes on as evidenced by the response of a cicada killer when I captured one and held it. Eventually one breaks away and skedaddles toward my neighbor’s lawn with the victor in hot pursuit. But the victory seems fleeting. Male cicada killers either have remarkably short memories or indefatigable egos as the aftermath of these vicious mêlées soon results in both males returning to their perches only to repeat the battle a short time later.

One perched on a shrub, the other perched on my garden hose. These two fellows are pumped and looking for a tussle.  Short forays from the perch sometimes result in spectacular aerial battles as each tries to lay claim to the territory where females will soon appear.  Video credit: M. J. Raupp

Perhaps one sunny morning only one of these fierce flyers will remain and the vanquished will have departed for less ardently defended turf in search of his own mate.  But for now, with coffee in hand, this is the best early morning bug show in my garden.     

Acknowledgements

For more information about cicada killers including videos of them in action, please visit Chuck Holliday’s magnificent cicada killer website, BIOLOGY OF CICADA KILLER WASPS.

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For the better part of the last moth inquiries about spotted lanternflies have poured into my mailbox. One of the most interesting dealt with the appearance of a remarkable “albino” lanternfly spotted by an inquisitive citizen. Albinism in humans and other animals results when cells responsible for producing melanin, a pigment responsible for color of skin, hair, and eyes, fail to produce enough melanin.  While relatively common in humans and other vertebrates, albinism is rare in insects. The pale orange spotted lanternfly that inspired this story is likely a recently molted fourth instar lanternfly nymph.  Time out, what the heck does that mean? Lanternflies belong to a clan of insects called the Hemiptera. These insects have sucking mouthparts to sip plant fluids.  Their development includes three life stages, eggs, nymphs, and adults. From spotted lanternfly eggs hatch polka-dotted black and white juveniles called first instar nymphs. As they grow from one stage to the next, they shed their exoskeleton just like our more familiar blue crab. Once they shed their old skin, they are almost pure white for a while as their new skin hardens and begins to develop color. The second and third instar nymphs are also black with white spots. However, the last nymphal stage, the fourth instar nymph, is bright red with black patches and white spots when its pigmentation is complete. The picture that inspired this episode is a newly molted fourth instar nymph in the process of turning from pale orange to brilliant red.

Last May in the DMV spotted lanternfly nymphs hatched from eggs. Newly hatched lanternflies are pure white and appear to be albino, but soon they turn jet black and are speckled with white polka dots. For months they have been feeding on leaves and stems of plants in landscapes and gardens. But a few weeks ago, we began to see the beautiful fourth instar nymphs, their scarlet bodies covered with black patches and white spots. Last week reports of adult lanternflies streamed in as lanternflies landed on people and walked across windshields of cars. It won’t be long before hordes of lanternflies gather on trees, shrubs, and vines to feed.   So, get ready DMV, here come the lanternflies.   

The most frequently asked question in the Bug of the Week mailbag over the past two weeks is why are we seeing so many spotted lanternflies? At least three reasons help us understand why this is the case. First, let’s go back a decade or so to spotted lanternflies’ original detection in Berks County, PA.  In the intervening decade, spotted lanternflies have established and are reproducing in more than fifteen states. They have spread more than 600 miles away from ground zero in Berks County. More people are encountering lanternflies simply because they now occupy a much larger geographic area in the US. Here in the DMV we have gone from a few infested counties in Maryland and Virginia in 2018, to more than 60 infested counties. Yes, folks lanternflies are also in the District of Columbia.

Second, as lanternflies spread either by natural means or with assistance from humans, new colonies are established. These new infestations often are founded by an egg mass or two, each with 30 to 60 eggs, that hitched a ride on lawn furniture, a camper, or maybe a metal sculpture. For several years these pioneers might be off the radar, undetected, as was the case with the initial introduction of spotted lanternflies in Pennsylvania. With abundant food sources like the invasive tree of heaven and other delectable plants and low levels of predators, parasites, and pathogens tracking their burgeoning populations, lanternflies can enjoy a period of exponential growth. As satellite colonies merge along the ever-expanding lanternfly front and as populations expand in the generally infested area, more people encounter spotted lanternflies.  

Third, size matters. Bigger insects are more commonly noticed than smaller ones. Tiny lanternfly nymphs hatching from an egg are but a few millimeters long. They scuttle about vegetation on the forest floor and low-lying shrubs feeding on more than 100 plant species. However, by July, brilliant red nymphs have molted into tawny coated adults an inch or more in length. Being more than 20 times larger than their youngsters, adults are more readily noticed as they cluster on the trunks of trees or take flight and move about the landscape in search of food, mates, and places to deposit eggs. In reality, due to the high mortality of juveniles which is the hallmark of most insect species, there are far fewer lanternflies now than there were back in May when eggs first hatched. I’ll bet you are finding little or no solace in this.

You think Superman is faster than a speeding bullet? Just watch this lanternfly nymph jet away from the nosy camera. Watch again at one twentieth of normal speed. That’s one speedy bug.  

What’s next for spotted lanternfly here in the DMV? Hordes of adult lanternflies and their attendant deluge of honeydew soon will coat vegetation underlying lanternfly infested trees. Honeydew is a substrate for the growth of sooty mold, a non-pathogenic mold that cloaks leaves and stems of plants, reducing the ability of plants to capture the energy of sunlight and conduct photosynthesis. More disturbing will be the arrival of sugar junkies, hordes of wasps and bees intent on enjoying the carbohydrate bounty.   

Is there any good news here? As we learned last autumn, scientists at Penn State documented more than 1000 attacks by spiders, mantises, birds, and other predators of spotted lanternflies. Also getting in on the act are naturally occurring soil fungi that have caused at least one lanternfly population to collapse in Pennsylvania. In addition, spotted lanternflies are reported to kill one of their favorite sources of food, invasive tree of heaven. Here’s hoping Mother Nature continues to send help in mitigating the invasion of spotted lanternflies.          

For more information on the biology and management of spotted lanternfly click here.

Acknowledgements

Thanks to James Murdock for providing inspiration for this episode. Thanks also to Eloise and Abby Kollins and Paula Shrewsbury for wrangling and spotting spotted lanternflies. Wonderful resources provided by scientists at Penn State University and Cornell University were consulted to prepare this episode. The fascinating article “A pair of native fungal pathogens drives decline of a new invasive herbivore” by Eric H. Clifton, Louela A. Castrillo, Andrii Gryganskyi, and Ann E. Hajek was used as a reference for this episode.

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From the Bug of the Week mailbag: What happens when a wheel bug goes for a spin? Wheel bug, Arilus cristatus

In previous episodes we met one of the toughest customers in Mother Nature’s gang of beneficial insects, the wheel bug. Wheel bugs play an important role reducing populations of noxious invasive pests like brown marmorated stink bugs and they also dine on important forest pests including fall webworms and other native caterpillars. This week we received the following message about a wheel bug that thought it might be fun to take a spin in a rotating core in a paper mill. Here’s the message. “I just thought you would be interested to know that this bug crawled inside of a core with a diameter of 4.41inches and this core went in our winder. He was rotated at 8000fpm for about 150 seconds start to finish and survived. Looks like he was a little dizzy but he ended up crawling out and then flying towards our control panel. So we determined he deserved to live so we caught him in a bag and took him outside. Crazy the endurance and survivability on this thing!!!” 

I am not exactly sure how far this predator spun around, but at 8000 feet per minute for 2.5 minutes seem like it might have traveled some 20,000 feet in circles. I don’t know about you, but I’d be dizzy, if I survived.

Wheel bugs are fierce generalist predators. Watch as this female stalks a dagger moth caterpillar. She slowly circles to the head of the caterpillar to deliver a lethal jab with her strong beak. After sizing up the prey with her left foreleg and extending her beak, she makes a lightning-fast strike to capture her prey. Forest pests like fall webworm caterpillars are also on the menu. This female snares a webworm while on a romantic interlude with her mate. Wheel bugs regularly dine on other pests including brown marmorated stink bugs. With other members of Mother Nature’s hit squad, they contribute to the decline of stink bugs in many parts of the country.  

To round out this episode, here is a little more about wheel bugs and how they roll when not in a paper mill. The wheel bug is a species of assassin bug and, as the name implies, it kills other insects. The common name, wheel bug, stems from the fact that this terror has a structure on its back that looks like a spoke-bearing medieval torture device. The function of this wheel is known only to Mother Nature and the bug, but not to me. The business end of the wheel bug is the powerful beak or proboscis stored between the beast’s front legs when it is not in use. Upon spying a tasty morsel, the wheel bug cautiously approaches, embraces the mark with long front legs, and impales the victim with the powerful beak. The wheel bug pumps strong digestive enzymes through the beak into the prey. These enzymes liquefy the body tissues of the hapless victim. A muscular pump in the head of the bug slurps the liquefied meal up through the beak. Young wheel bugs use protein from their prey for growth and development and adult females convert prey into eggs. In autumn, the well-fed female wheel bug lays barrel-shaped eggs in clusters of several to more than one hundred usually on the bark of a tree. Eggs hatch the following spring in May and June.  Small wheel bugs, called nymphs, are magnificent creatures with bright red abdomens and orange antennae. They dine on a wide variety of insects including caterpillars, sawfly larvae, beetles, and other bugs. In most years, I feel lucky if I witness a half dozen of these monsters at work in the wild. With plant nurseries and landscapes laden with invasive pests like stink bugs and spotted lanternflies, it is not unusual to see scores of wheel bugs stealthily stalking and assassinating their stinky marmorated cousins and other invaders. How much benefit results from greater numbers of these assassins remains to be seen, but we hope that these bugs and other naturally occurring predators and parasites will help stem the onslaught of brown marmorated stink bugs, spotted lanternflies, and other invasive species. If you encounter wheel bugs, please heed this caution. While holding and admiring a wheel bug, I learned firsthand, so to speak, that the wheel bug could deliver a memorable, painful poke with its beak. If you keep wheel bugs as pets beware, try not to handle them directly or you too may become an unwitting victim of this clever assassin.

Acknowledgement

We thank Joshua Colgin for providing images and the fascinating story that inspired this episode.

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