The Bees in Your Backyard--A talk by Olivia Carril

Interesting talk at the Princeton Public Library on bees, by Olivia Carril, co-author of a new book on North American bees called "The Bees in Your Backyard". Most engaging was her clear passion for the subject, which is expansive, given the 4000 species of bees in this part of the world. Each species has its own story, its own special approach to living a bee's life, and new ones are being discovered all the time. Just in the process of doing her doctoral work in Utah, she found 46 new species, and a new species of bee was recently verified in Central Park.

She began with speculation about how bees came into being back in the days of dinosaurs, when primitive magnolia flowers served as the stage where early predatory wasps could evolve into bees that used nectar and pollen for food. Making the transition easier was the similar nutrients content of insects and pollen.

Along with explanations of how to distinguish bees from other insects and from each other, she gave some insights into the myriad lifestyles bees have evolved: where various bees sleep through the night, and the underground preparations for spring.

I asked about how the presence or absence of various species of bees could affect habitat restoration efforts. She said that the first bee species to be lost when habitat is disturbed are the ground-nesting bees and those that are highly specialized and therefore specific about which flowers they pollinate. The specialist pollinators are highly vulnerable when the particular native plant species they've adapted to utilize are lost. Plant species reintroduced to an area after a long absence, and whose specialized pollinators have long since disappeared, will likely still get pollinated, she said, by generalists--bees that pollinate a great variety of flowers.

When asked about what to plant to accommodate the needs of bees, she listed three of the best plant families for attracting bees: sunflower (Composite), mint and pea families. I mentioned the phenomenal insect community (50+ species of insects and spiders) that comes together on our disks of boneset flowers each August, and a woman suggested that narrow-leaved mountain mint, a local wildflower found in meadows, also draws a very diverse insect crowd. Many posts having to do with boneset can be found on this website by typing the word boneset into the search box. Here's an example of the diversity to be found if one looks closely.

Some other notes:

• More bee diversity in dry climates, due to there being fewer fungi to prey on the bees. Southeast U.S., which has a hot, humid climate, has relatively low numbers of bee species.
• Carpenter bees use the same galleries year after year, enlarging them each time
• Bumble bees prefer abandoned rodent holes for building their nests
• Miner bees dig "gopher" holes in the ground. Most of their lives is spent underground. 
• Cuckoo bees parasitize miner bees, using a strategy similar to that of cowbirds. 
• Bee wolves paralyze bees and take them back to their nests for food

Master Gardeners of Mercer County are hosting a June 18 event on bees. 

Boneset Days

Boneset is in bloom, and as some may remember from posts on this blog last August, boneset puts on its very own, unparalleled pollinator festival each year. Every pollinator in the Princeton area--large or minute, scary or comical, linear or round, irridescent green or conservative beige--shows up to drink what must be the insect world's version of manna.

No other wildflower draws such a diverse and numerous crowd. I thought that last year's photo gallery of 50 species visiting the flowers was fairly encyclopedic, but this year I'm finding many additional species, all of which means more posts are in the making.

For every photo posted, ten more are taken, sorted through, cropped and otherwise adjusted. Documenting the biodiversity on this singular flower could be a life's work. Pleasant enough, though, with the feint aroma of honey all around, and always something new to discover.

Flies On Boneset

This is the third post documenting and roughly grouping nearly 50 species of insects and spiders that have been visiting a cluster of seven boneset plants in my backyard.

No other wildflower in my backyard, with the possible exception of the meadow rue that bloomed earlier in the season, has attracted anywhere near the variety and sheer numbers of species that this unassuming boneset has.

Again, the grouping of all these insects together is based on a guess as to what constitutes a fly. If all of these nine photos are of different species, then the species count rises to 29.

Update, August 30, 2009: Thanks to Keith Bayless, who provided latin names for many of these insects (see comment section)
First photo: Tachinidae: Trichopoda pennipes?
(Tachina Fly)

2 Calliphoridae: Lucilia? sp.

3 Muscidae: Coenosia?

5 Tachinidae

6 Dolichopodidae: Condylostylus

7 Hymenoptera: Halictidae: Augochlorini

8 Hymenoptera: Halictidae: Augochlorini

9 Calliphoridae: Pollenia?

Late Season Wildflowers

A couple on the street the other day recognized me as a botanist at large, and asked about a flower they'd seen, like boneset but lacking the fused, perfoliate leaves. They summoned a photo on their iPhone. "Late-Flowering Thoroughwort," I announced. Given the length of the name, some people slim it down a bit by replacing "thoroughwort" with "boneset". It's a beautiful, delicate-looking plant, even though it toughs it out along roadsides, and is more common in the wild than boneset. In the garden, it sometimes seems fickle, dying out in one spot then seeding into another. This may have to do with drying out, because the consistent rains this summer have coincided with its most prosperous year in memory. Eupatorium serotinum is the latin name.

Another favorite, one of the few exotics I still like to plant from my less native-oriented days, is showy stonecrop, here shown with the shrub Virginia sweetspire gaining its rich fall color in the background. This kind of stonecrop (Sedum spectabile, unless you really want to learn the new latin genus name, Hylotelephium ) has a flower that gradually shifts color in the fall from light pink to deep red to a chocolate brown.

New England aster can look a little lanky in the garden until it finally blooms, at which point it looks just right. It feeds what few monarchs we've had during their fall migration south to Mexico.

Once again, the sunchokes (Helianthus tuberosa) were allowed to grow, despite vigorous spring pulling of hundreds of shoots. Their splendid flowers this time of year distract from their imperialistic underground spread. What's needed is a human to come along and eat its tubers throughout the winter, so that only a few will be left in the ground to sprout in the spring. Sounds like a win-win, if the resident human will get his act and his appetite together.

The "Fireworks" goldenrod (Solidago rugosa) grows at the Barbara Boggs Sigmund Park on Hamilton Ave. It's a native originally named by a friend from Durham days, Ken Moore of the North Carolina Botanical Garden.

Where Have All the Pollinators Gone? -- Summer, 2021

Wherein is discussed the season's paucity of pollinators, the curiously prolific presence of hornets, and possible causes thereof. 

With the coming and the going of this year's autumnal equinox, it's time to look back on a long summer and ask, "What happened?" Or, more precisely, "What happened to the happening that didn't happen?" 

There's lots of talk about how insects are in decline and that we need to plant more wildflowers to support them. A local ecologist and avid birder, David Wilcove, co-wrote an oped in the Washington Post about the danger posed by insect decline, and the need to better monitor populations, as is done with birds.

In past years, a summer's climactic buzzfest on the boneset

This year, there was a steep decline in pollinator numbers in Princeton. Each year I grow a banquet of wildflowers in my backyard for all manner of insects to feast upon. In past years, they'd come from near and far, their numbers building through summer, climaxing in late August in a buzzfest on the boneset. Though mountain mint is another great draw for insects, in my yard it was boneset in particular, clustered here and there in the garden, that in past years drew the multitudinous shapes and sizes of the insect world. Its broad disks of tiny white flowers seemed like a Serengeti in miniature, an open plain perched conveniently four feet above the ground, teaming with life. It was a chance to see the insects close up, they being so focused on the nectar or each other that they took little notice of me.

Then, two years ago, and again last year, the numbers of insects were down--still numerous but not enough to stir that late-summer's jazzy feeling of frenzied activity. 

2021: An astonishing diminishment

And this year? This year, boosted by the rains, the wildflowers grew to fabulous size. Broad arrays of blooms mounted on multiple stems stood at the ready. In early summer, while periodical cicadas held center stage, the numbers and variety of pollinators were building nicely. 

But then, as the wildflower meadow's heavy hitters--the cutleaf coneflowers, Joe-Pye-Weeds, bonesets and wild sennas--unveiled their fabulous blooms for the mid-summer festival of nectar, the insects were no-shows. Abundant flowers had few pollinators, and sometimes none at all. Diversity dwindled to some tiny somethings, a few bumblebees and even fewer honey bees. 

Sifting through possible causes for the decline

Possible causes for the dramatic decline have been offered: extreme heat, more homeowners fogging their yards for mosquitoes, expanding monocultures of lawn and invasive species. Or perhaps the climate-changed winters have messed with insect dormancy.

The rains of July, the rains of August

What I have particularly noticed over the past three years, however, is the increase in rain during the summer. Rutgers precipitation data for NJ show increased precipitation particularly over the past two years in July and August. Not only has there been more rain, but the intensity of the rain has increased. The sound on the roof is different--one can hear and even feel the extraordinary density and weight of the rain. The deep trauma of Hurricane Ida was the climax among multiple intense storms before and after. The ground and foliage are literally getting beaten up by these deluges. Insects try to hide during storms. Some live in the ground. The harder the rain, the fewer places to hide, and the more likelihood that a ground nest will be flooded out. All that sustained moisture could increase the risk of disease, which an entomologist friend says can play a big role in bee numbers. 

Some of us noticed other changes as well. Gladly, the numbers of odorous house ants invading our kitchen were down from previous years. Mosquitoes in our area seemed relatively rare in early summer, though numbers surged later in the season--tiny ones, probably asian tiger mosquitoes. 

A proliferation of hornets

What was most striking and very strange was a proliferation of hornets. Last year, I seldom saw them, but oftentimes this summer, approaching a patch of flowers, the first thing that would catch my eye was not pollinators but the hornets that can prey upon them. 

We have two kinds of insects called hornets. One is the European hornet, which looks to me like a stocky bee--black markings with a particularly thick yellow abdomen.

The other is the bald-faced hornet, a native insect with black markings and a whitish face. 

Both are hard to photograph because they don't land, but instead keep cruising around the flowers. Periodically they may bump into a bee that was minding its own business on a flower. The contact lasts a split second, then the hornet flies on. The purpose of this brief harassment is not clear. 

Here's a bald-faced hornet in adult and larval form, found on a fragrant of nest someone left at the curb. Both kinds of hornets live in nests that are in or hang from trees. The paper they make, by the way, is beautiful when looked at close up.

Why the proliferation of hornets, cruising relentlessly among the flowers with a sense of urgency but no clear goal? Maybe they just seemed more numerous due to the lack of other insects to catch one's attention. Or maybe the fact that they live in elevated, waterproof nests allowed them to better survive the intense storms. 

The seeds of change planted over centuries

In any case, this summer was not the lively pollinator party I was used to playing host to, both in my backyard and at our Botanical Art Garden (the "Barden") in Herrontown Woods. One interpretation is that the carbon dioxide we've been scattering to the winds is now coming home to roost, in the form of weird winters and intensified storms. In Princeton, basements flooded that had never flooded before. It's not a stretch to hypothesize that many bees also find themselves newly vulnerable to the merciless power of the rain. And then, on the sunny days when pollinators can make it to the flowers, there's the haunting background of patrolling hornets.

In a docile wasp, some small comfort

As students returned to the university, I remembered helping my daughter move in to Whitman College two years ago. In the courtyard, I had noticed thousands of wasps cruising just above the grass. It was a mating dance, of no danger to the parents and students passing by, of blue-winged wasps. I had recognized their distinctive orange abdomen from those that would frequent the flowers in my backyard, a mile away from campus. 

This year, I had seen only one in my yard, and wondered whether their improbable annual ritual was still playing out at Whitman College. 

What I found on Sept 2nd were perhaps a hundred wasps flying in their usual criss-cross manner a foot above the lawn. Some seemed fatigued by it all, and would abandon their flight to sit among the grass blades for awhile. Though their numbers were down from the thousands I'd seen two years prior, I was glad to see any at all. And a student sitting in a lawn chair, scrutinizing his computer, told me there had been many more ten days prior when students first began moving in. 

It would be nice to think that the paucity of pollinators I observed this summer was an isolated affair. But others around New Jersey have made similar reports. An entomologist friend who lives in Oregon told me that he's seen "a very significant decline in pollinators" this year, probably due to drought, though he also said that each species can vary in numbers year to year. 

An ark is built of something more than flowers

We take so much for granted in our lives. When something breaks, that's when one has to study up and figure out how it works, what went wrong, and how possibly to fix it. The insect world has been taken for granted since forever. Annual bird surveys benefit from a community of avid birders, but citizen scientists who are up to speed on the mind-boggling diversity of insects are fewer to come by. We thought we could just plant some flowers and the insects would come, but the needs appear to be far deeper than that. 

A Good Hornet That's Not a Hornet

Finally, I got a photo of the salt and pepper-colored bee-like thing that was flying around our boneset this summer. Unlike the fifty or so other species of insect and spider that for weeks were visiting or residing on our mini-grove of boneset flowers, this one would never land, but instead patrol the airy avenues, in and around the flowers, as if hunting for prey.

The wonders of the internet led me to a Penn State factsheet on the creature. Turns out it's a baldfaced hornet, although you may know it by its scientific nickname, good old Dolichovespula maculata, in the family Vespidae.

As with many common names, this one's a bald-faced lie, because the insect is not a hornet at all. The only true hornet in North America is an introduced species. What was patrolling my boneset was a kind of yellowjacket. Besides not being yellow, it also varies from other yellowjacket species in building its nests in the air rather than underground. Yellowjacket species can be considered to be beneficial, in that they prey on other insects that could be considered a nuisance, but the baldfaced hornet has the added benefit of preying on other species of yellowjacket. I'm not sure the logic of that sentence would survive scrutiny, but I'll stick with it for now. The notion of beneficence will be lost on anyone who disturbs a nest, but if the nest is out of the way, then the recommendation is to leave it be.

Riding on the DR Canal towpath yesterday, I found this nest suspended on a tree branch over the canal. I didn't have my better camera, but got close enough to give the general idea. One of them flew over to me, but as usual I didn't react, and it flew away. The nest has small vents on top to release hot air but minimize how much rain can get in.

When I was a kid, some sort of wasp built a nest on my bedroom window. I got to watch them applying the paste to build each new layer of walls, and of course had the boyish joy of later poking a hole in the nest with a stick before running back inside. Such is the early training to become a naturalist.

There was even a convenient explanation for why I finally found one sitting still, perched on a flower. Baldfaced hornets prey on other insects in order to feed their young high-protein food, but as summer wanes there are fewer young to feed, and they start shifting over to feeding on nectar.

A Raingarden's Quiet Riot of Wildflowers

Half of my backyard is raingarden, and this is what it looks like right now. it could not be mistaken for evergreen shrubs trimmed to look like cannonballs. It's a celebration of life, and the party's in full swing right now. Most of these grow wild along the canal and a few other spots in town.

Joe-Pye-Weed is the tall one with the pompom blooms. Rose Mallow (Hibiscus moscheutos) is the large white flower.

Cutleaf coneflower (you can see why it used to be called green-headed coneflower)

The rose mallow hibiscus is variable--sometimes white with a rose center, sometimes pink.

If you kayak up the Millstone River from Carnegie Lake, you'll see these lining the banks.

A bit of an optical illusion here. Cardinal flower isn't that big. Green bullrush is the sedge in the foreground, just to the right of the cardinal flower, with hibiscus in the background and boneset on the back right. Boneset is the king of pollinator attractors. To the left of the huge-looking cardinal flower is purple loosestrife (a non-native that seeded in and can be invasive, but which I'm leaving in for now).

Ironweed has clusters of small flowers at the top of a tall stalk.

There are lots of different yellow flowers. This one is cup-plant, which can grow ten feet high. I found it growing next to the dumpster at Mark Twain's house in Hartford, CT. It doesn't grow wild in the Princeton area, but is a native. The small white flowers are late-flowering boneset.

Though they do fine in regular garden soil, these native wildflowers also thrive in parts of the garden that are scooped out a bit and have runoff directed to them, from downspouts, driveways, or patios. That's basically what a raingarden is.

Surprises Along the Boardwalk

When the township, with the help of a grant from the J. Seward Johnson, Sr. Charitable Trust and considerable initiative by the Friends of Princeton Open Space, built the long boardwalk below Coventry Farm, it provided a convenient link from the Great Road and Farmview Fields Park over to Mountain Lakes Preserve. From a botanist's point of view, it seemed moreover a great place to show off native wetland plants. The boardwalk extends three feet high over a corridor typically kept wet by seepage from Coventry Farm. Unfortunately, early planting efforts fell victim to the smothering growth of an invasive plant called reed canary grass, here seen growing over the edges of the boardwalk like a green wave.

On a recent visit, however, a few self-planted native wildflowers were found holding there own in spaces left open by the reed canary grass. Here's some arrow-leaved tearthumb, so called because its stem is raspy if you run your fingers down it.

Moths grazed on a goldenrod.

Virginia creeper imitated topiary on a fencepost.

An elderberry bush showed promise of providing edible berries in years to come.

Clumps of ironweed were about to add purple blooms to the picturesque view.

A prairie grass called purple top gave the meadow a colorful sheen at the Great Road end of the boardwalk.

Most intriguing was a clump of boneset. Type "boneset" into the search window at the upper left of this webpage and you'll find many posts documenting the seemingly endless variety of insects and spiders that take up residence for the month of August in its miniature metropolis of white flowers.

This particular boneset did not disappoint. A close look at the center of this photo holds a surprise--for people as well as a hapless wasp that had been feeding on the nectar.

Waiting just under the flowers was a praying mantis, which had grabbed the wasp and was now enjoying its lunch. The accumulation of wasp legs on the leaf below suggests the praying mantis is particular about which pieces of the anatomy it consumes.

Heading back towards Mountain Lakes, the seeds of green bulrush,

and the prospect of a fine picnic for humans in a week or two.

Boneset Ants

This seventh post cataloging creatures attracted to flowering boneset shows a couple kinds of ants. The second one was probably part of a nearby hatching.

One insect I didn't get a photo of--the "weird one that got away"--was seen only once, and looked like a cross between an oversized mosquito and an undersized, white and black crane fly.

Add these three and we're up to 48 distinct species on seven boneset plants in one Princeton backyard.

My apologies, by the way, to any and all who actually know anything about insects and spiders, for the questionable way I bunched these bugs in rough categories. Names will be attached to photos as this botany-type blogger becomes enlightened about the bewildering variety of insects and spiders out there.

Boneset Butterflies and Moths

The sixth in a series of posts cataloging all the varied life attracted to a backyard boneset plant. The last two are probably the same, but one was bluer than the other, so both are included.

The kind of butterfly in the fourth photo was by far the most common--essentially present all day long.

These five beauties, plus one I haven't tracked down a photo of, bring the count to 45.