Month: April 2025

 

 

The return of some delightful 70-degree weather last week heralded the return of lovely parasitoid wasps in the subfamily of Hymenoptera known as the Ophioninae. Each year we welcome these nocturnal visitors to my porch light as one of the harbingers of spring. They regularly appear on the first 60-ish degree evenings in March at my porch light. This year I discovered my first one last week on a windowsill near my houseplants. The mystery of how it got into the house remains unresolved, but we were still delighted to greet it.

Beneath the glow of my porch light, an Ophioninae wasp grooms its antenna and then taps its front foot in time with the music.

Ophioninae wasps belong to a large and important family of membrane-winged insects known as ichneumon wasps. Ichneumon wasps perform the important ecosystem service of biological control by parasitizing some of our most important pests, including corn earworms and white grubs. However, they also attack other non-pestiferous insects including the larvae of butterflies. Some years ago, we collected a beautiful caterpillar, the larva of the tiger swallowtail butterfly. After eating leaves like a ravenous teenager, it formed a remarkable chrysalis resembling a dead leaf. We placed the chrysalis in a terrarium and anxiously awaited the appearance of a beautiful swallowtail butterfly. Events took an unexpected turn when a feisty looking wasp emerged from the chrysalis instead of a gorgeous butterfly. You see, unbeknownst to us, prior to the capture of the swallowtail larva, a parasitoid ichneumon wasp had visited it. The female ichneumon wasp likely grappled with the caterpillar before stinging it and depositing an egg within.

The fascinating part of this story is that the parasitoid inside the swallowtail did not immediately develop and emerge from the caterpillar. This clever parasitoid waited for the caterpillar to feed and grow before beginning its own development. The tiny invader then completed its development and emerged as an elegant ichneumon wasp. Parasitoids with this type of delayed development within a host are called koinobionts. Many species of koinobionts synchronize development with that of their host by responding to changing levels of hormones produced by their host during growth and development.

Ichneumonid wasps can be a little testy when sharing a droplet of honey.

Returning now to the present, if you would like to see ichneumonid parasitoids, switch on your porchlight on a warm spring evening, and see who arrives. Don’t be surprised if several pale orange Ophioninae ichneumons appear. If you dare, do as we do and invite them in for a drink. As you see in the video, a little honey and water seemed just the right tonic for these busy parasitoids. After they had their fill, we bid them adieu and returned them to the wild. Perhaps my hospitality will be rewarded in a few weeks by these ichneumons in the form of koinobionic attacks on the pesky caterpillars and white grubs that perennially plague my flower beds. 

Acknowledgements

The fine references “The Insects: an outline of entomology” by P.J. Gullen and P.S. Cranston, and “Subfamily Ophioninae” by I.D. Gauld and D.B. Wahl, were used as references for this Bug of the Week. Thanks to Dr. Shrewsbury for spotting the Ophioninae wasp which was the inspiration for this episode.

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One of the joys of spring is observing the antics of insects and their relatives as they resume their activities outdoors. To celebrate this annual renaissance, the Department of Entomology hosts an award-winning Insect Petting Zoo as part of the Maryland Day Gala at the College Park Campus of the University of Maryland on Saturday, April 26, from 10 am to 3 pm. The Insect Petting Zoo is in the Plant Sciences Building on the ground floor directly across from Regents Drive parking garage.

Come to the Insect Petting Zoo, Saturday April 26 at the University of Maryland, College Park. Travel around the world to meet rocking Vietnamese walking sticks and giant Australian walking sticks pretending to be dead leaves. Amazing Malaysian leaf insects will try to fool you and watch out for the whip scorpion and its smelly surprise. Hold a giant tarantula if you dare, and look at, but don’t touch, the black widow spider. Meet the deadliest creature on our planet, blood-thirsty mosquitoes, and pet a friendly, furry Eastern tent caterpillar. Fast moving green tiger beetles will prowl their cage while blue death feigning beetles will be stuck in second gear. Learn why carpenter bees make holes in your deck and why iconic honeybees and their kin are imperiled in our rapidly changing world. Hope to see you at Maryland Day.

This year’s petting zoo will feature an incomparable ensemble of friendly, ferocious, and creepy crawly creatures. A visit to the petting zoo is sure to delight insect aficionados of all ages. This year’s extravaganza features bugs from around your home and around the world. Giant Lubber locusts straight from the Everglades of Florida will reveal their favorite delicacies and how they defend themselves from being eaten. Vietnamese and Australian walking sticks are true masters of disguise and giant Madagascar hissing cockroaches will blow your mind with their size and agility. Watch out for the Whip Scorpion that has a clever trick up its sleeve, or should we say its tail, to thwart attacks by enemies. If you are lucky, you might catch a glimpse of a Black widow spider with a bright red hourglass tattooed on her abdomen, a ferocious Green Tiger beetle hungry for fresh meat, or a Carpenter bee buzzing about its cage. The arts of trickery, mimicry, thanatosis, and other feats of deception and disguise will be revealed by Blue Death Feigning beetles, the European sowbug (roly – poly), darkling beetles (armored stink beetle), the remarkable, petite orchid mantis, and strange leaf insects.

The Insect Zoo is not just a treat for the eyes. Children of all ages will have the chance to hold and touch (with parental permission of course) a multi-legged millipede from the desert or a hairy Eastern tent caterpillar from a cherry tree. The very brave may even have a chance to hold a giant tarantula. If touching isn’t your thing, then you can listen to the buzzing of a bee or the hissing of a cockroach from Madagascar. Meet face to face the number one killer of humans on the planet – dreaded bloodthirsty mosquitoes. Curious smells are on the menu as well. Learn what unwelcome house guests have the aroma of cilantro and discover an arachnid with the pungent odor of vinegar. If you are feeling sociable, investigate the wonders of perhaps our most important social insect, the honeybee. Stop by the invasive species corner and meet dastardly Emerald Ash Borers, the nefarious home invader Brown Marmorated Stink Bug, and the newcomer in our region, Spotted Lanternfly.

 

Children can collect insect stickers and the first 600 visitors may take home a Terrapin Lady Beetle to release in their garden to put a beat-down on insect pests lurking there. 

Don’t miss The Swamp – If you enjoy the life aquatic, be sure to stop by The Swamp across the hall and learn how dragonflies capture their prey and how diving beetles extract oxygen from water.

So, come one, come all to explore Maryland Day and the Insect Petting Zoo!

Please click here to learn more about Maryland Day and the location of the Insect Petting Zoo.

Acknowledgements

Bug of the Week thanks Dr. Paula Shrewsbury for organizing the Insect Petting Zoo and Dr. Bill Lamp and his crew for organizing The Swamp at Maryland Day. Special thanks to Todd Waters and Chris Sargent for making our arthropods the happiest six and eight- legged creatures on the planet.

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A week or so ago, during a Q and A session at a meeting, I was asked by one nature enthusiast why large black bees were bombarding him in his back yard. Without fail, about this time each spring humans who venture too near a child’s wooden play set, wooden benches or railings, mailbox posts, decks, or houses with cedar siding are divebombed by territorial male bees. The bees have nothing against humans. They are simply jealously guarding potential wooden nest sites from interlopers. Interlopers include other male carpenter bees or almost any other creature that comes into range, including humans.  

Wooden structures like this play set bear telltale damage as woodpeckers search for carpenter bees inside the wood. Male carpenter bees zoom around nearby sensing that nubile female bees will soon emerge from these galleries. They divebomb other competing males and nosy humans, aggressively defending their mating territory. When females emerge, they will quickly be mated by diligent guy bees patrolling nearby. Once inseminated, females build new galleries in wooden structures creating nesting sites for their young.

Why do they do this? Here’s the deal. Female carpenter bees build galleries in wooden structures to serve as nurseries for their young. Male carpenter bees go to great lengths to convince potential mates of their worthiness by selecting and defending prime nesting sites. When other male carpenter bees approach defended territories, remarkable aerial battles ensue. Swooping, grappling, and biting often result in both combatants tumbling to earth before one withdraws from the fray. I watched one victorious male guard a nesting site and soon a lovely and somewhat coquettish lady carpenter bee arrived. She rested on the wooden bench guarded by her suitor and a short but energetic romantic interlude ensued. As far as I could tell, the male flew off somewhere, perhaps for more battles or romantic conquests, but the female bee had different matters to attend. After mating, the she bee begins the task of excavating a hole in the wooden structure to be used as a nursery for her brood. Her powerful mandibles create a slightly oval to almost perfectly round hole as she penetrates the wood to the depth of about a half inch. She then makes a right angle turn and continues tunneling parallel to the grain of the wood excavating a series of brood-cells in a linear tunnel. In a piece of wood removed from one of the benches, I observed several tunnels more than a foot in length, some of which branched into secondary galleries. Each tunnel contained as many as thirteen individual brood-cells.

To construct each multichambered gallery represents more than a month’s worth of chewing and one has to admire the determination of these industrious gals in excavating a home for their young. After the chambers are built, they are meticulously cleaned and filled with bee bread, a nutritious mixture of pollen, nectar, and secretions from glands on the female’s body. Bee bread serves as the food for the young carpenter bees. Starting at the end farthest from the entrance the female deposits an egg in each brood-cell. Each egg hatches into a legless larva that eats bee bread and develops during the course of spring and summer. In brood-cells furthest from the entrance, older larvae complete development first, pupate, and then after emerging from the pupal case in late summer these new adults push their way past brothers and sisters to escape the gallery and search for nectar and pollen. As summer wanes and autumn waxes, newly minted bees forage during the day and return to their galleries to spend the night. With the end of blossoms in the fall, carpenter bees return to their snug tunnels to chill out until the following spring, protected from the ravages of winter.

In locations where carpenters are present, watching humans duck and cover is almost as entertaining as watching aerial battles among male bees. Male bees lack stingers and although the gals are equipped to sting, I have never been stung by one nor have I heard of anyone who was harmed by these fascinating creatures. Carpenter bees do cause some damage to wooden structures. And once woodpeckers find a structure housing carpenter bees, they get busy and can do some remarkable destruction as they peck holes in the wood searching for carpenter bee babies for dinner. Nonetheless, these entertaining native bees provide important services by pollinating our trees, shrubs, and crops.

At past events such as Maryland Day at the University of Maryland at College Park, which will be held on Saturday, April 26 this year, a thousand or more people visit our Insect Petting Zoo. At the zoo our resident carpenter bees receive much interest and attention. In years past, several children and a few courageous adults held male bees and were fascinating by the buzzing sounds and vibrations generated by flight muscles that power their wings. In discussing the antics and activities of carpenter bees, I was heartened to learn that most folks take a “live and let live” approach to dealing with the carpenters. As one lady put it, “This is their world too, you know.” I do know, and well said.

Acknowledgements:

Special thanks to Frank Bruno and the folks at the Howard Conservancy who served as the inspiration for this episode. “Bionomics of large carpenter bees of the genus Xylocopa” by Gerling, Velthuis, and Hefetz” was used as a reference for this Bug of the Week.

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In the past month, we explored the questions of how to know where periodical cicadas of Brood XIV might be seen, how to protect your trees from cicada damage and whether or not we should be worried about being bitten or stung by cicadas.  Recently, one of the most frequently asked questions about periodical cicadas is, “when will cicadas appear?” Bug of the Week has been tracking the life history of periodical cicadas for almost two decades, so let’s look at some historical data and see what it reveals.

The “when” question will often be answered with, “when soil temperatures reach 64 degrees Fahrenheit.” This answer comes from brilliant work performed almost 60 years ago by J. E. Heath who discovered that cicadas emerged when “soil temperature at 20-cm depth in seven locations averaged 17.89 C … regardless of date.” This answer holds fairly well even to this day. However, it is not always possible to know just when the magical 64 degrees at 8 inches below ground hits. We explored this in a slightly different way by observing the emergence of straggling Brood X cicadas in the DMV in 2020. In 2020, several locations reported sightings of impressive numbers of Brood X cicadas that appeared one year early. These cicadas are known as “stragglers”. Stragglers are periodical cicadas that emerge years prior to or after the major portion of their brood mates. Often, 17-year cicada stragglers emerge four years prior to the emergence date of rest of the brood. In 2017, Maryland Brood X stragglers appeared on May 14 in Columbia and Gaithersburg. In addition to emerging four years early, sometimes stragglers emerge one year early and this is exactly what happened in 2020. Using data collected in 2020 from the brilliant Cicada Safari App, the very first cicada out of the ground in the DMV was seen on April 19, just south of Towson, Maryland. This one was an extreme outlier. Cicada emergence really picked up in the DMV on May 14, and by May 24, 25% of emerging cicadas were out of the ground. By May 28, 50% of cicadas had emerged, and just few days later, on May 31, 75% of all cicadas had emerged in DC, Maryland, and Northern Virginia. So, if 2025 is anything like 2020, or previous years for that matter, cicadas will be regularly seen as a trickle in some parts of their range in late April or early May with a tsunami hitting in the last two weeks of May and early June as these teenagers are up and out for the Cicadapalooza. Here in the DMV in 2020, the last cicada to emerge was reported in mid-June. Due to a normal life span of two to four weeks, don’t be surprised to see adult cicadas alive and well into the waning weeks of June, but, sadly, in most locations by the 4th of July, their moment in the sun will be all but finished and nothing but a fading memory.

 

 

Unfortunately for most of us in the DMV, cicadas are likely to visit only Botetourt, Lee, Russell, Scott, Smyth, Tazewell, and Wise counties in western Virginia this year, with no hope of seeing them in DC and little hope of a visit in western Maryland. But for other states ranging from Georgia to Massachusetts Brood XIV is expected. Of course, the emergence in Georgia will begin weeks ahead of the emergence in Cape Cod. Back in the days of Brood X in 2021, Georgia reported adults in late April but in northern parts of Brood X’s range in northern Illinois, the adult show didn’t get underway until late May according to iNaturalist.     

For seventeen years, nymphs of Brood XIV cicadas have been developing underground. While digging a hole in my yard years ago, I discovered a quartet of periodical cicadas about 14 inches underground. Notice their white eyes and uniformly tan bodies. Here we see a periodical cicada not quite ready to emerge resting at the top of its exit gallery beneath a cinder block. Just behind its red eyes, the dorsal surface of the cicada is uniformly tan. On the evening of its emergence, notice how the dorsal exoskeleton of the fully developed cicada nymph bears two distinct black patches just behind its eyes. I think these are really good clues to help figure out when cicadas are about to emerge in your area.

On a more local level, how can we tell when the big jailbreak is close at hand? The images and video accompanying this episode provide some clues. For weeks prior to emergence, we witnessed almost-ready-to-go periodical cicadas peeking out from their galleries. In these images, notice that just behind the cicada’s brilliant vermillion eyes, the dorsal surface of the cicada’s exoskeleton is uniformly tan in color. On the evening or day of emergence, notice how the exoskeleton of the cicada bears two jet-black patches just behind its eyes. In more than a dozen emergences of periodical cicadas attended by the Bug Guy, this seems to be the clue that cicada emergence is very close at hand or underway. When you see these dark patches, the big show is about to begin. Get ready to enjoy!

Acknowledgements

Three cool articles, “Combining data from citizen scientists and weather stations to define emergence of periodical cicadas, Magicicada Davis spp. (Hemiptera: Cicadidae)” by M. J. Raupp, C. Sargent, N. Harding, and G. Kritsky, “The ecology, behavior, and evolution of periodical cicadas” by K. S. Williams and C. Simon, and “Thermal synchronization of emergence in periodical ‘17-year’ cicadas (Hemiptera, Cicadidae, Magicicada)” by J. E. Heath formed the foundation for this episode.

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