Thursday, September 19, 2019

A Pettable Blue-Winged Wasp's Mating Frenzy on Princeton Campus



This post gives a demonstration of wasp petting, and describes a funny thing that happened while helping our younger daughter move into her college dorm.

There's a wasp that's both pretty and pretty harmless. It's named after its wings, which reflect blue in the sunlight, and is easily identified by the rusty orange abdomen with two yellow spots. Scolia dubia, as it's called in latin, is a frequent visitor to the boneset in our backyard garden, more methodical in its nectar drinking than many other wasps.

It's understandable that people are afraid of wasps, given the stings most of us have endured after accidentally stepping on a yellow jacket's nest out in the field. But not all wasps are social like a yellow jacket, or even have nests. A female blue-winged wasp (males cannot sting) has no nest to defend, but rather digs down to lay its egg on an underground grub, then leaves the egg to hatch, consume the conveniently paralyzed grub (usually a larva of the June bug or the Japanese beetle), and emerge on its own as an adult.

Here's an example of how docile these creatures are as they peacefully sip nectar.



This year's visits seemed less frequent than in previous years, leading me to wonder how the species is faring, given all the talk of pollinators being in trouble.

That question was answered in the most unexpected way. Helping our younger daughter move into a dorm for her first year at Princeton University, I noticed one of these blue-winged wasps on a flower near the entryway. Then, on the third or fourth trip in with stuff, I happened to look over at the lawn in the courtyard, and noticed that hundreds of the wasps--let's call it an even thousand--were roaming in zig-zaggy patterns just above the grass. It wasn't at all obvious what they were doing. They looked lost, each flying around and back and forth in its own orbit. Perhaps the grounds crew had blocked their nest, leaving them to search in vain for the entrance. One passerby joked that the wasps were a metaphor for incoming freshmen. Another suggested that the University should take action on what seemed like a threat to the students.

My sense was that any danger was more perceived than real. Having spent many hours this summer photographing the various pollinators visiting the backyard boneset, seeing how harmless are the various bees and wasps when preoccupied with other matters, I waded out into the fray to have a closer look. Were they in fact lost? Or hunting? Or mating? There was no sign of prey, and if they were mating, then why was there so little interaction?


The first clue came only after watching them for awhile. Every now and then, some 20 or 30 of the wasps would suddenly converge on one location in what appeared to be a mad scramble in the grass. It's not easy to photograph wasps zipping around your ankles, but I did manage this photo.

And also this video of one of the sudden convergences. If they were fighting, it appeared brief. If they were mating, it looked pretty clumsy.


Some internet research made it clear that the goal of this mass, planar mingling of wasps was to mate. Some websites state that the males and females do a figure eight-shaped mating dance. Others suggest that those cruising the grass are males waiting for a newly mature female to emerge from the ground. They then converge on the female and compete for a chance to mate. If one's heart can go out to a wasp, my heart went out to the hapless female who, having just emerged as an adult from its underground birthplace, must immediately deal with a frenzied crowd of males seeking to pass along their genes to the next generation. If that is true, though, the sheer numbers and intensity of the gathering suggest that a whole lot of hatching was going on that day, and might the males have also just emerged from the ground?

I did manage to get up close and personal with one of the convergences, close enough for a voyeuristic view of a male and female taking a tumble amidst the grass blades, clearly mating, with another male up next to them, bending its abdomen and probing in vain. What was surprising was how quickly most males gave up on the project, quickly returning to their holding patterns above the grass.

Here's the online description that best fits what I saw, in a 2016 paper entitled "The Scramble Competition Mating System of Scolia dubia" 
Males of the wasp Scolia dubia search for emerging females by flying low over the ground in areas, such as lawns, that contain the immature scarab beetles upon which the grubs feed. When an adult female emerges and is discovered by a searching male, other males often join the discoverer, forming a frenzied ball of males around the female. When captured along with these males by an observer, a freshly emerged female continues to attract males even after she has mated, presumably because her scent continues to be detected by other males. Some males of S. dubia also search for mates in shrubs and trees encircling a lawn as shown by the sexual response of these males to a frozen but thawed female placed in a shrub or tree known to be visited by flying males. Male flight activity peaks around midday but then diminishes as the afternoon proceeds. 
It was in fact late morning, sunny, warm, and some of the wasps were flying about the branches of the evergreen tree in the middle of the field. But there are many lingering questions. Do these gatherings happen only once per year, or multiple times in the summer? Was this lawn special in some way, or does this happen all over town? And how did these rituals play out before lawn mowers were invented?


One thing is clear. These docile wasps do us a favor by preying on a notorious garden pest--the Japanese beetle. Maybe some September, walking home from the Dinky station, you'll cut through campus and some late-flowering thoroughworts will catch your eye. There, in the clouds of white flowers, blue-winged wasps will be busy living their quiet lives, minding their own business while doing good deeds, their solitary pursuit of nectar giving no clue as to the elaborate choreography that brings them into being.

Friday, September 13, 2019

Attracting Pollinators With Boneset and Thoroughwort


Many people sing the praises of mountain mint and goldenrod for attracting pollinators, but my two favorites are a duo that produce large disks of small white flowers for a long stretch in mid to late summer.

This has been a banner year for boneset and its more numerous but lesser known sidekick, late-flowering thoroughwort.


With a name that spreads like the pagoda-shaped stems that carry its flowers, late-flowering thoroughwort adorns the sides of roads and railroads this time of year. I've seen it cover a whole abandoned field in Montgomery,


and there's a lone specimen blooming at the end of the track at the Dinky station.


It could be called a successful weed, and sometimes it can look a little ragged, perhaps influenced by how much rain comes. But this year it was the most elegant plant in the garden, its loose clusters of flowers like delicate hands reaching out to pollinators.

Late-flowering thoroughwort (left in this photo at the Westminster parking lot raingardens I care for) blooms just as boneset (right) is fading, which this year made for a seamless handoff between the two. Though boneset is comparatively rare in the landscape, it will make seedlings to increase its numbers when planted in a garden.

The two species can easily be told apart by checking the leaves. Boneset has pairs of leaves that are "perfoliate", which is to say they fuse to wrap around the stem. Thus the latin name Eupatorium perfoliatum.

By contrast, the leaves of late-flowering thoroughwort have petioles that extend the leaf away from the stem. The "serotinum" in its latin name, Eupatorium serotinum, means late summer. We could call it the serotinal thoroughwort, but we don't. In the common name, the word "wort" means plant, and if there's anything thorough about a thoroughwort, it's the copious blooms.

Both these wildflower species rise each year to the perfect height for viewing all the varied insect life they attract. Spend some time in that honey-scented space around the flowers and you'll discover an ecosystem in miniature, the flowers being a stage where the protagonists not only feed on nectar, but also look for mates, and sometimes put their lives on the line.


You might think it dangerous to be in proximity to the many kinds of bees and wasps that frequent this floral saloon, but I have never been stung in all my hours immersed in quiet observation.


I've even taken to petting the more docile creatures, like this "solitary" blue-winged wasp. Knowledge can cut through fear. It helps that the more aggressive insects, such as "social" wasps like yellow jackets, spend their summers elsewhere.

If anything, the pollinators are at much greater risk than I, with an occasional preying mantis showing up to snare a fly,



or a brilliantly disguised ambush bug lying in wait for a bumble bee.

Here's the ambush bug that was hiding in that previous photo.



Each plant has a time-release approach to flowering, with some clusters of flowers opening just as others are fading. Week after week in the summer, working in tandem, boneset and late-flowering thoroughwort continue to play host to a shifting cast of insect characters--each with its own traits, backstory and motivations--all the while adding ornament to the garden.

Monday, September 09, 2019

A Lost Public Garden


There's a planting in the field at Turning Basin Park, across the street from the canoe livery. It looks like a curved hedge, but if you take a closer look, there's a sign buried in the foliage.

A butterfly garden was planted there years back, and a lovely sign erected to commemorate the effort. It was a good idea, a nice gesture, and then everyone went their separate ways.

A decade ago, helping WaterWatch with annual workdays at Turning Basin Park--part of Princeton University's freshmen bonding activities before the semester began--I noticed the forsaken garden and spent some time cutting down the woody growth that was starting to shade out the flowers. Each time it took no more than a half hour of skilled attention to discourage the weeds enough to keep the garden blooming for another year.


But WaterWatch passed into history, and with it my annual prompt to volunteer some care for this garden. Up grew the mulberry trees,

and the catalpas,

the wineberry,

and the vine that will eventually claim all of Princeton, porcelainberry.

Gone are the butterfly-attracting flowers, as Turning Basin has returned to the default landscape of mowed grass, trees, and whatever. Shall we fault the planters of this garden who didn't follow up? Kids grow up and girlscout troops come and go. Maybe fault the lack of government budget for anything beyond unskilled, custodial maintenance of our public landscapes? Let's just say that love moved on.

Thursday, August 29, 2019

Synchronized Hazel Sawfly Larvae Pose for the Camera

This seems to be the summer for balletic poses by caterpillars and caterpillar wannabes. First came the dramatic pose of Datana contracta, happened upon in a patch of lowbush blueberries at Herrontown Woods.

Yesterday, fellow FOHW board member Sally Tazelaar sent a photo of another balletic display, this time seen on her husband Kurt's hazelnut tree in their backyard. The caterpillar-like creatures munch as a team, working from the edge of the leaf inward, and when disturbed, they pose as a team in surprising symmetry. Unlike humans who pose to be noticed, these larvae are more likely posing to hide. Maybe they are pretending to be dentations--part of the leaf--like the teeth in the uneaten leaf next to them. Doesn't fool us, but then again, we aren't the predators they are hiding from.

Some internet research suggests they are not caterpillars but instead the larvae of the hazel sawfly--Craesus septentrionalis for all the latin lovers out there. Hazelnut trees tend to be loners in Princeton's woodlands, the better to avoid being happened upon by hungry sawflies.


Thanks to Sally for the photo!

Thursday, August 22, 2019

Visits By Butterflies

One perk for us stay-in-Princeton types in the summer is the fabulous display of native flowers--the tall, lanky sort that are like slo-mo fireworks, growing, growing, then bursting forth with a show of color. My backyard is filled with them, and I make a point of going out there not only to appreciate their extraordinary work, but also to see what sorts of insects they attract. Achieve a certain stillness, forget all the other things left undone, and a whole new world may open up. In its own miniature way, insect life can be as surprising and compelling as a trip to exotic lands.


Butterflies are a good entry point. Mimi, a friend of this blog, sent me an email, excited about having seen a common wood nymph. She didn't have a camera the first time, but it returned and she was able to get a photo with her phone. Thanks, Mimi! She noted that it was hanging out around the black-eyed susans, morning glories and beebalm, and that the host plant is purple top, a common native grass in our fields.



I haven't seen a wood nymph, but have had visits from a common buckeye, maybe because we have bottlebrush buckeyes in the garden. This one's visiting a boneset, a plant that hosts a whole ecosystem of insects and spiders this time of year.

The upswing in monarch numbers has created more opportunities for magical moments. (This one's visiting ironweed.) Their flight is extraordinary to watch. There's the strength, speed and agility they display when chasing each other, and then there's the way they navigate a garden. A couple evenings ago, one came and stayed awhile. The garden surrounds our patch of grass, so to stand on the lawn and watch a monarch weaving in and out and over the flowered landscape, seeming to check out every plant yet rarely landing and then just for a sip, is like standing at the center of a merry go round. There's a whimsical, carnival ride quality to its flight, as it darts, then coasts, then darts again, changing direction on a dime. It flies with extraordinary confidence, yet seems unsure where it wants to go. This may simply be a matter of my not understanding its motivations. Whatever its aims, there's a feeling of blessing when a monarch comes to the garden. It lives up to its name, for long with the whimsy is a regal, ambassadorial quality, as it graces each plant with its presence before moving quickly on to the next.


Maybe this year I will finally learn the different sorts of swallowtails. This one appears to be a male two-tailed swallowtail, visiting a giant cup-plant in our backyard.

From the link, it looks that females have more blue.

Another magical moment this summer came unexpectedly while clearing trails at Herrontown Woods of debris. Deep in the woods, I lifted a stick and up flew what seemed like a large moth, the size of a monarch but white, pale like a luna moth but squarish in overall shape. It flew up into the canopy and disappeared. Its presence was reassuring, a sign that something of nature's depth persists in our altered world.



Tuesday, August 20, 2019

Invasive Mile-a-Minute Spreading at Princeton Battlefield


Ever find yourself caring deeply about something the rest of the world ignores? We all pick our battles, and here's a really good one for the Friends of Princeton Battlefield and/or our governing institutions to pick.

Princeton has been graced in many ways of which it is not even aware, and one of those is the up-to-now absence of Mile-a-Minute, a thorny annual vine that grows up and over everything if allowed. Gardeners beware. This one's particularly nasty, and though it has gained a foothold in nearby areas, I've encountered it in only two locations in Princeton. One location is the Princeton Battlefield. The other is on the gravel road in to Rogers Refuge. Each year I pull it out, but by the time I remember to do it, a few of the vines' little blue berries have matured, so the infestation has been growing.

Obviously, my efforts are not enough. The town of Princeton has fortunately hired the NJ Invasive Species Strike Team in recent years to treat invasions by new species, but the Battlefield is state owned, and because of a lack of intervention it is now serving as a seed source that will affect all Princetonians, and not only for Mile-a-Minute.



Another issue at the Princeton Battlefield is the massive invasion by porcelainberry--a vine that rivals kudzu in its capacity to sprawl over anything and everything. Its overwhelming presence may seem to dwarf the problem with Mile-a-Minute, yet it can also be seen as proof that we really need to catch these invasions early, before they get out of control. Porcelainberry is not only at the Battlefield, but is also dominating large areas all along the Stonybrook in Princeton.

Here are the copious berries produced by porcelainberry vines as they smother the flowering dogwoods planted in 1976 for the nation's bicentennial. The berries turn pretty colors--blue, purple, pink, or white--thus the name, and the original appeal of the plant. But the plant has escaped the usual checks and balances that otherwise sustain balance in nature.

Birds eat the berries of porcelainberry and Mile-a-Minute, thus the concern that what's allowed to grow at the Battlefield will impact the rest of Princeton.


The Friends of the Battlefield group, by the way, has been doing a great job knocking out big stands of bamboo around the Clark House during its annual workday in April. Look in the distance in the photo and you'll see an open field, with only a small remnant of bamboo back near the woods.

But bamboo doesn't spread by seed, and so poses no threat beyond the Battlefield's borders. Volunteer sessions can slow down porcelainberry and Mile-a-Minute a bit, but for any lasting benefit, we need to get some professional intervention. Maybe the Friends of the Battlefield could apply for a grant.

In the meantime, be on the lookout for its distinctive triangular leaf, put on some gloves, and pull it out.


Friday, August 16, 2019

Nominations Sought for "Women and Wildlife" Awards

Each year, the NJ nonprofit Conserve Wildlife Foundation gives awards to women who do outstanding work to protect New Jersey's wildlife. I've been fortunate to perform my Sustainable Jazz at their event, which takes place at Duke Farms. Nominations will be accepted through this coming Monday, August 19. See information provided by Conserve Wildlife below.

Do you know a woman who should be celebrated for protecting New Jersey’s Wildlife? 
You are invited to nominate an exceptional woman for using her time and talent to protect New Jersey's wildlife. Women in science have come a long way since a National Geographic editor called Jane Goodall "the blond girl studying apes." That 'girl', of course, went on to become a world renowned researcher famous not only for her meticulous field studies of chimpanzees, but also as a tireless advocate for the natural world.

While much progress has been made, girls considering a career in science still struggle to find role models. For 14 years Conserve Wildlife Foundation has been celebrating women who protect New Jersey's imperiled wildlife. Help us inspire the next generation of women leaders by nominating an exceptional woman today!

Awards are made in recognition of achievements, advances for women in wildlife professions, efforts to increase awareness of rare species and the habitats they depend on, and contributions to New Jersey's wildlife. Nominations will be accepted in three categories:Leadership, Inspiration and Education.

The nomination form will be accepted through Monday, August 19, 2019. Nominations submitted last year will automatically be reconsidered this year. For more information, contact Liz Silvernail at 609-292-3707 or liz.slivernail@conservewildlifenj.org.

Thursday, August 15, 2019

Some Summer Gardening Success at Princeton Schools


There can be a tendency for school gardens to suffer neglect during the summer, but many in Princeton are doing surprisingly well. There are the gardens on the grounds of Riverside Elementary that are best known and continue to flourish, but quite a few others as well. Behind Community Park Elementary, there was a wildflower garden in the courtyard behind the school that over the years got taken over by the most aggressive wildflowers--sunflowers and goldenrods, which have those strong rhizomes that other wildflowers can't compete with. This year, a friend and CP parent, Georgette, decided to renovate the garden and asked me to co-teach an after-school class for the purpose. After a lot of work, some of it done by the kids, who went at it with considerable zest and confidence, the garden now is transformed, with hills of corn planted Indian-style, a tipi trellis for string beans, a few wildflowers and switchgrass from the original planting, and some unusual crops,


like cotton,

and amaranth. The quinoa, not shown, looks a lot like the amaranth, which makes sense since they are both in the Amaranthaceae family. It was interesting to discover that a common edible weed in our summer gardens, lambsquarters, is in the same genus as quinoa: Chenopodium.

Some of the weeds at Community Park, as the photo shows, are hard to reach (hope that's not evidence of some serious deferred maintenance),

but we did manage to pull out enough foxtail grass, pilewort, and velvetleaf (photo) to get the intended plants ready for the opening of school. The velvetleaf, by the way, is in the same family as cotton, the Malvaceae, as is the native Hibiscus in the wetland below.


Now's a good time to take a stroll down Walnut Street and stop by the Princeton High School ecolab wetland. Native hibiscus, joe-pye-weed, wild senna, giant cup-plant all are at a perfect height for viewing from the railing. I was over there the other day and happened upon a woman holding a large bouquet of flowers (bought, not picked from the wetland) and a young man all dressed up and serious, who appeared to be proposing. A proposal of marriage next to our wetland? I think we're onto something with this wetland garden thing.


The wetland was completely unfazed by the recent heavy rains. I just hope the school survived. This fan on the wooden performance stage brings back memories of the flood damage a couple years back, but a sign said they were waxing the floors.

And behind the highschool, the gardens may not be proposal-worthy, but a few of the raised beds are in good shape. Though the bed on the right shows how foxtail grass will take over any bed that's not cared for, the native cutleaf coneflower (tall yellow flower) and New England aster we planted a few years back have expanded to two beds instead of the original one. Some angel gardener must be helping this happen.

The coneflowers in turn will attract more yellow in the form of goldfinches as the seeds begin to ripen.


Visited a month ago, Littlebrook Elementary has a fine crop of milkweed feeding the monarchs, and a nature trail that handyman Andrew Thornton has been tending to with the help of some sophomore volunteers.


Monday, August 12, 2019

Parallel Prairies in Ann Arbor

Most summers in recent years I've traveled to Ann Arbor for a reunion performance with a jazz/latin group I've played with since 1983 called the Lunar Octet. It's also a chance to see my old neighborhood down along Easy Street, where our first house came with a beautiful garden of poppies, delphiniums, blue thistles, Miscanthus grasses and other perennials. These I loved and tended to, though by the time we headed to North Carolina my gardening interests had shifted strongly towards native plants. I have a friend in that old middleclass neighborhood who in many ways lives a life parallel to my own. Jeannine Palms leads the Wet Meadow Project, which in collaboration with volunteers and city staff has transformed much of the nearby sprawling turfdom of Buhr Park into native wet meadows designed to catch runoff. She often gets kids to help out, and calls them "superswampers."


The project is flourishing, with many of the prairie species we have, like sweet bergamot, and a few we don't see here in central NJ, for whatever reason.

Gray-headed coneflower is one of the midwestern species whose range doesn't quite extend to New Jersey. You'll see in the lower left corner of the photo some Queen Anne's lace, a non-native which Jeannine almost certainly works to limit in her wet meadows. It's a pretty flower, but a trip to the midwest makes one realize how it tends to take over in ways we have not yet seen in New Jersey. Other invasives of midwestern fields, like teasel and spotted knapweed, have yet to become extensive in the east to my knowledge, but it may only be a matter of time.

Some of my favorite prairie wildflowers are Silphiums that are much more numerous in the midwest, like rosinweed, compass plant, cupplant and prairie dock. The bright yellow flowers rise on tall stems out of the enormous basal leaves of prairie dock.

The towering Silphiums in the background are cup plant, a species that we now have in Princeton at the Riverside Elementary gardens and our Herrontown Woods botanical garden.

Along with some of the Silphiums, like the big leaves of prairie dock in the background, Ann Arbor's meadows also have some very attractive goldenrods that have the desirable quality of not spreading aggressively underground. Stiff goldenrod (not yet blooming in the foreground) is one of these, as is showy goldenrod.

During my visit this past month, I arrived late for one of Jeannine's workdays, just in time to find her walking home with a young assistant--a girl full of wonder at the natural world. They had been hanging some tallow soap in the Edible Forest--yet another patch of grass that Jeannine had transformed into a botanically rich oasis for the community. She had heard that the soap will deter deer. We saw a hawk land in the very top of a tall evergreen tree in the distance, making an insistent, plaintive sound that could have been the hawk's prey or the hawk itself. We wondered whether it might have a nest there. When it flew over to a a telephone pole, a rodent hung from its talons--all part of a food chain that Jeannine nurtures with her native wet meadows.

Sunday, August 04, 2019

The Very Dramatic Caterpillar Eating Wild Blueberry Bushes


Before I saw the blueberries, I saw the caterpillars eating the blueberry bushes. They were distinctive in the braiding of their bodies into a cluster on the stem. I snapped a photo of their distinctive black heads, yellow necks, and striped bodies, and must have brushed against the bush, because when I looked at them again, surprise!


They had all contracted their bodies into a dramatic pose that completely hid their heads, as if they were the caterpillar world's equivalent of a synchronized swim team. What's the logic here? Look down and away and the potential threat will disappear? Seems human, somehow--a caterpillar's artistic pose to symbolize society's head-in-the-sand response to climate change.

A nearby bush had been stripped of leaves but still had a few blueberries.

While highbush blueberry bushes tend to be solitary, the lowbush blueberries I have seen in woodlands, whether in North Carolina, on top of New Jersey's Mount Tammany, or in Princeton's Herrontown Woods grow clustered in colonies on a hillside.

These heavily shaded patches and the measly crop they bear seem to me stunted remnants of a past glory, when periodic fires would sweep through, thinning the canopy and setting the stage for a burst of new growth from the resilient roots of the blueberries, which then prospered in the partial shade of the scattered trees. Thick bark and decay-resistant leaves are common traits of trees that are adapted to periodic fire. Oaks exhibit these traits in Princeton, their leaves persisting on the ground as fuel for fires that no longer come.

The most dramatic example of the distortion caused by fire exclusion that I've witnessed was in a woodlot preserved as part of Bennett Place, a Civil War site in Durham, NC where the war's largest surrender took place. In the past, trains passing close by would throw sparks, causing low-burning fires to sweep through the woodland, promoting the growth of fire-adapted post oaks and shortleaf pine. I like to call these rejuvenating events "mildfires"--the relatively tame wildness of a healthy nature--in contrast to the destructive wildfires we're used to hearing about in the news. The woodland--perhaps more like a savanna--was a favorite place for Duke University botanists to find a rich understory of wildflowers prospering in the open shade. As they remarked on this or that rare species of wildflower, they must have sampled the berries from the broad patches of blueberries that persist there. As trains have become less sparky, and people more fire-averse, the less fire-resistant, fast-growing trees like willow oaks have grown up, while the deepening shade and the accumulation of unburned pine needles have stifled the wildflowers. The once-thriving "fire-climax" ecosystem is begging for a fire that never comes, as the old trees slowly succumb.

Though the exclusion of periodic fire has also made Princeton's woodlands less natural, we can see in the caterpillars' partial munching--some shrubs eaten, some not--the persistence of another aspect of balance in nature, worked out over millenia of coevolution. No species can survive long if it wipes out its food source. Long-term stability thrives on balance. New species introduced from other continents lack these elaborate checks and balances. Stiltgrass smothers large swaths of Princeton's preserves because nothing eats it. Our forests have suffered a series of shocks, from chestnut blight in the 1920s, gypsy moths in the 1970s, and now the emerald ash borer--all from introduced species that lacked the checks and balances that evolve over time.

The common name for our very dramatic caterpillar, "contracted datana," is hardly a common name given how few of us have heard of it, and is merely an adaptation of its latin name, Datana contracta.  Come to think of it, the heads of the caterpillar look a lot like blueberries. Their collective ducking seems to be saying to a hungry predator, "Please move along, no food here!"