Pocket Prairie

by Carl Strang

This is the time of year when the view out my back window is best.

The diversity of blooming wildflowers hits its peak in late July.

The diversity of blooming wildflowers hits its peak in late July.

My neighborhood for the most part is a wildlife desert. It’s amazing what a little habitat can bring, though. These native prairie flowers attract diverse pollinators, and bumble bees for instance always are present in the daylight hours. The red blooms are royal catchflies, which never fail to bring hummingbird visitors in July and August. Later, goldfinches will be after the seeds in the purple coneflower heads. My original planting plan is history, as most of these plants are seeding into the tiny spaces left between. My main work has shifted from planting to thinning, keeping the better competitors at bay so as to maintain a balance of biodiversity. That makes me a member of this community, too.

Literature Review: Plant-Pollinator Ecology

by Carl Strang

Bombus impatiens queen on red clover flower head

Bombus impatiens queen on red clover flower head

Soon we’ll have flowers blooming and bees buzzing. Here are some studies of interactions between plants and their insect pollinators from last year:

Burkle, Laura A., John C. Marlin, and Tiffany M. Knight. 2013. Plant-pollinator interactions over 120 years: loss of species, co-occurrence, and function. Science 339:1611-1615. They studied forest understory pollinators around Carlinville, IL, not far from St. Louis, comparing present-day species to those documented by a researcher in the late 1800’s. They found that 50% of bee species have gone extinct there. Changes have included the conversion of most forest and prairie land to agriculture, and an increase of 2°C in spring and fall temperatures which has resulted in phenological mismatches. Focusing on the interactions of forest floor forbs and bees, they found that only 24% of the original interactions had survived, though this was compensated in part by new ones, “such that the absolute difference of interactions lost was 46%.” All 26 species of forbs have persisted. The lost bees were predominantly specialists, parasites, cavity-nesters and those whose interactions with the plants were weak because of limited phenological overlap. They found a reduction in pollinator visits per flower, and expressed concern about this, about the loss of stabilizing redundancy in the entire network, and the continued weakening of phenology matches.

Rasmussen, C, et al. 2013. Strong impact of temporal resolution on the structure of an ecological network. PLoS ONE 8(12): e81694. doi:10.1371/journal.pone.0081694    They looked at day-to-day changes in pollinator-plant connections in a Greenland tundra ecosystem, and compared them to the season-wide summary typical of past studies. They found that the difference is significant. Many indirect links between species that had been implied by the static network proved to be impossible in the dynamical ones because the species are active at different points in the season. The nature of generalist vs. specialist species also becomes transformed because of the limited phenological availabilities of the various species. Their methods involved a focus on a 500m x 500m study area, with randomly selected plants (or 5x5cm clusters where individual plants were difficult to separate), observed for 40-minute intervals.

Eggs, B., and D. Sanders 2013. Herbivory in spiders: the importance of pollen for orb-weavers. PLoS ONE 8(11): e82637. doi:10.1371/journal.pone.0082637 They looked at the diets of juveniles in two species of orb-weavers, and found that pollen, ingested when the spiders recycled their webs, made up 25% of their diet. Flying insects (flies and hymenoptera) made up most of the rest. The pollen ingestion was not incidental, as the spiders deliberately use an external digestive process to consume pollen grains too large to be eaten without such treatment. They regard these spiders as omnivores rather than carnivores.

Clarke, Dominic, Heather Whitney, Gregory Sutton, and Daniel Robert. 2013. Detection and learning of floral electric fields by bumblebees. Science 340:66-69. They showed experimentally that bumblebees can read electrical information from flowers. The bees themselves transfer electrons that quickly can change flowers’ electrical fields, so that bees can read which flowers have or have not been visited recently by others. Intrinsic electrical qualities also can be added to color and shape to help bees identify flower species and suitability for visits.

Mayslake Animal Update

by Carl Strang

Every season contains the seeds of the next, and this was very true at Mayslake Forest Preserve last week. The migration season is well under way, though mainly it still features species that wintered in the southern U.S. rather than the tropics.

This winter wren was a classic example. Its kind invented skulking, but this one came out for a few seconds into plain sight.

This winter wren was a classic example. Its kind invented skulking, but this one came out for a few seconds into plain sight.

This male yellow-rumped warbler, in contrast, was not hiding. The challenge with him was that he seldom held still for more than a second. There was always another insect to chase.

This male yellow-rumped warbler, in contrast, was not hiding. The challenge with him was that he seldom held still for more than a second. There was always another insect to chase.

The wren and the warbler both nest well to the north, and will be with us only a short time.

Home hunting was another theme. The first bumblebee queen I saw this year was a Bombus bimaculatus.

She didn’t hold still, and didn’t stick around for long, but the yellow center of the second abdominal segment is visible in this blurry photo.

She didn’t hold still, and didn’t stick around for long, but the yellow center of the second abdominal segment is visible in this blurry photo.

Bumblebee queens in spring are probing for holes in the ground where they can start their colonies. Some animals make their own holes, and I found what may be a test dig by Mayslake’s pair of coyotes.

It was in an elevated site, and the hole was a foot in diameter, but not yet completely excavated. I’ll check on it occasionally. Coyotes only use dens to shelter their young.

It was in an elevated site, and the hole was a foot in diameter, but not yet completely excavated. I’ll check on it occasionally. Coyotes only use dens to shelter their young.

The abundance of the growing season still is in the future for most, however.

This fox squirrel was making do with some dried rose hips from the bush outside my office window.

This fox squirrel was making do with some dried rose hips from the bush outside my office window.

Clearly we are in a season of promise and preparation.

First Flowers

by Carl Strang

Spring advances, despite the unpleasant weather that has denied our enjoyment of much of it so far. As I have sloshed through the rain and the mud at Mayslake Forest Preserve, I have been finding the first of the woodland wildflowers, so I guess it hasn’t really been as cold as I have thought.

Bloodroots have been blooming for what seems an extended period, though. Perhaps the temperatures have been marginal for them.

Lots of spring beauties have taken advantage of last fall’s burn in the south savanna.

These haven’t hit their peak, yet.

Views of pollinators still have been few.

In addition to this bee fly, I have seen the first of the year’s queen Bombus impatiens bumblebees.

The expansion of the Dutchman’s breeches population is gratifying.

These make me smile whenever I see them.

Ongoing restoration clearing of buckthorn has shown the quickest response by trout lilies, which now can be found in great numbers in many places on the preserve.

Their flowers haven’t been open on many days, yet, needing temperatures above 50F or so.

It’s a little early yet to do a serious phenological comparison, but so far, compared to the last two years at Mayslake, first flower dates in 2011 have been the earliest for one species, latest for 2 species, and between those of 2009 and 2010 for 5 species.

Odd Bee Identified

by Carl Strang

The Beespotter folks got back to me in recent days and confirmed that the odd bumblebee I reported earlier was indeed a male Bombus bimaculatus.

This confirms in my mind that bimaculatus is an early-season species in northeast Illinois, as males appear toward the end of a species’ season. In support of that notion, in recent days I have seen increasing numbers of Bombus impatiens, the common late-season short-tongued species, as they replace the declining bimaculatus.

Odd Bee, and Tour de France Catalpas

by Carl Strang

In the late afternoon of July 4 I was looking out the kitchen window at my prairie garden plots. Bumblebees, Bombus bimaculatus, were swarming the Culver’s root

and wild bergamot.

They were not showing very good fidelity, individual bees frequently going between the flower species rather than sticking to one. Then I saw a bee that immediately sent me grabbing for my camera. Like the bimaculatus it was moving between Culver’s root and bergamot.

This bee was almost all yellow.

What was wrong about it was the black abdominal segment in the middle of the yellow. If not for that, I would have passed it off as a Bombus fervidus. But fervidus should have a black strip between the wings, as in this one I photographed last year:

I did a web search, and found a photo of a bee somewhat similar to this one at a University of Illinois website. It was identified as an aberrant male Bombus bimaculatus. The eyes of the one in my yard seemed small, however, for a male.

Also, it seems early in the season for males to appear unless, as I suspect from last year’s observations, bimaculatus is limited to the early part of the year and is replaced by another short-tongued species, B. impatiens, in the latter part of the season. I decided to resolve this problem by creating an account in Beespotter and submitting my photos to the specialists there. I’ll report back with the results later.

P.S. In last night’s TV coverage of the Tour de France, the broadcast announcers’ table was placed in front of some catalpa trees in bloom. The British and American announcers all wondered aloud at one point what the trees were. I’m not sure which catalpa species it was, but clearly these or their ancestors had been transplanted from North America to that location in Spa, Belgium, for their floral display at this time of year.

Late Bee?

by Carl Strang

On May 20 at Mayslake Forest Preserve I saw this queen Bombus impatiens bumblebee digging in a small area in the south savanna.

There had been many days of warm weather, and so I would have thought by that point all the queens would have found nest sites and begun their first broods. Already I was seeing worker Bombus bimaculatus in my garden at home. So, what was the digging queen’s story? I don’t know any other reason why a queen would dig. If she sensed a cavity in the soil below that spot, a little digging might get her a nest hole. It seemed late to be searching still. Perhaps she had a nest, lost it, and had to start over.

On the other hand, given her species it’s not a total disaster. Bombus impatiens is the one species whose activity spanned the entire season at Mayslake last year. I saw them as late as October 5. The latest other bumblebee was a B. griseocollis on August 25. I haven’t been studying bumblebees long enough to know whether this is typical, but in any case it seems there still is plenty of time for this impatiens queen to get going.

Mayslake Autumn Flowers

by Carl Strang

The time has come to close the book on the wildflowers of Mayslake Forest Preserve for this year. I don’t expect to find any more new ones this season. Now I have a long list of species with first flowering dates for 2009 that I can compare to those of the same species next year. Such phenological studies are good indicators of climate trends, as well as suggesting whether a given year is relatively early or late in its seasons.

The final goldenrods to begin flowering were old-field goldenrods, which I found in a small colony in the savanna.

Old-field goldenrod b

A much more abundant woodland species there is the side-flowering aster.

Side-flowering aster 1b

In the prairies and meadows, heath asters added to the grand finale of the flowering season.

Heath aster 1b

In places around the edges of the prairies a few sneezeweeds were blooming.

Sneezeweed 1b

Obedient plant, the plant that’s also a toy (if you move one of the flowers by pushing it with your finger, it stays where you moved it), pops up in the prairies here and there.

Obedient plant b

Bottle gentian, a bumblebee-pollinated species, also occurs in Mayslake’s prairies.

Bottle gentian 1b

And I’ll close by panning back to show a couple of scenes. In an earlier chapter I introduced the bur marigold. It has come to dominate a zone around the stream corridor marsh.

Bur marigold stream marsh 2b

Finally, here is part of the prairie.

Mayslake prairie flowers fall b

It’s not too late to get out and enjoy the season’s flowers, at Mayslake and other open places.

Miscellaneous U.P. Notes

by Carl Strang

In this final chapter of my Michigan vacation account, I will bring together assorted observations of other animals and sights. None of this truly counts as inquiry, except that travel and the exposure it gives us to new places leads us to make comparisons with our familiar environment. Such comparisons often lead to questions and inquiries on down the line.

At Muskallonge Lake, after completing my investigation at the beach, I went for a walk along the state park’s trails.

Muskallonge Lake trail b

There were spectacular views of Lake Superior from elevated points, and flocks of migrating songbirds to investigate.

Tahquamenon Falls State Park is named for various waterfalls along the Tahquamenon River. Especially spectacular are the upper falls.

Tahquamenon Falls upper 1b

After a summer in which I made good progress in my knowledge of Illinois bumblebees, I was interested to find that in that part of the U.P., as back home, only one common species of short-tongued, generalist bumblebee is active at this point in the season. Here it’s Bombus impatiens; at the tip of the U.P. it was the beautifully marked Bombus ternarius.

Bombus ternarius 2b

B. ternarius is a northern species that does not extend its range down to Illinois.

One of the more charismatic birds that one hears and, sometimes, sees in the north woods is the pileated woodpecker. Here is a tree that has been well worked by that species.

Pileated work b

Beauty on a smaller scale, which provided a reminder of the season in transition, took the form of this aspen leaf lying on a trail.

Aspen leaf 1b

I spent most of my time at Whitefish Point. Here is a small scene I found especially compelling.

Whitefish Point 7b

As I walked out from the point to the parking lot for the final time, I found an enchanting little animal crossing the trail.

Smooth green snake 3b

Smooth green snakes occur in many places, but are so well camouflaged that we seldom have the good fortune to see them.

On my final morning at the Tahquamenon Falls campground, I found that a large number of moths had been drawn to the restroom building’s lights.

Nepytia canosaria 1b

These were nearly all males of the same species, emerging all at once.

Nepytia canosaria 3b

Nepytia canosaria, the false hemlock looper moth, is a common northern species whose larvae feed on a wide range of coniferous species including firs, hemlock, pines and spruces.

Bumblebee Dynamics

by Carl Strang

In my last update on bumblebees  at Mayslake Forest Preserve I described the 5 species I had observed to that point. In the subsequent few weeks there have been a couple of changes to report. First is the apparent addition of a 6th species.

Bombus pennsylvanicus 1b

I believe this to be Bombus pennsylvanicus. At first glance it is very close to Bombus auricomus, which I described earlier. Both are relatively large bumblebees, both have lots of black on the thorax (especially on the sides), and both have segments 2 and 3 of the abdomen all yellow. However, auricomus has a cleaner, sharper look. All the yellow areas are bright, pure yellow. The black areas are unblemished by hairs of other colors. Both black and yellow areas are sharply defined, and correspond to the edges of body segments. If I am correct in my identification, pennsylvanicus has a muddier look. The yellow of the dorsal abdomen spills a little onto the first segment as you can just see in the above photo. Also, the yellow area of the posterior dorsal thorax has some black hairs mixed in, and the black on the sides of the thorax has some yellow hairs mixed in.

The more astonishing change is the nearly total disappearance of Bombus bimaculatus over the past three weeks. Through July, this was the most common bumblebee at Mayslake, with numbers exceeding those of all other species combined. I was away a week for Roger Raccoon Club , and returned to find the bimaculatus nearly gone. Now I see at most one or two a day. The other common small species, Bombus impatiens, continues essentially unchanged.

Bombus impatiens worker b

This is my first year of following the bumblebees at Mayslake. I don’t know if this disappearance is usual, and I don’t know what it means. I doubt that the species has a limited season, as bumblebees generally continue through the summer. Some of the native, solitary bees are specific to a single flower species and thus have defined seasons, but bumblebees are generalists. They are known to monitor changes in flower abundance and to travel miles, and so may have abandoned Mayslake for an abundant appearance of other flowers elsewhere. Disease might have impacted one colony, but for all the local colonies to be affected with no obvious change in other species seems unlikely (though the uncommon Bombus griseocollis also has been absent in August).

One day earlier this week I saw a couple odd looking bumblebees that seemed clumsy on the flowers.

Bombus bimaculatus or griseocollis male b

Their markings were like those of griseocollis or bimaculatus, not precisely fitting either. They had enormous eyes, and were larger than most workers of either species. Photos showed them also to have unusually long antennae. These are males. What, if anything, their sudden appearance has to do with the absence of their species’ workers is another piece of the puzzle that needs fitting.

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