Stocking up for the winter

We wait all summer for New England Aster to show off its beautiful lilac-purple to bright pinkish flowers, and it never disappoints.

Dense clusters of flowers attract a variety of pollinators in the fall with bright-colored flowers, lots of pollen, and nectar.

Besides being a very attractive addition to the garden, New England Aster is an important late-season resource for pollinators, especially Monarch butterflies as they fatten up before fall migration.  Flower nectar and pollen are energetically harvested by lots of bee species, as they top off their hive or overwinter nest supplies.

Honeybees, which I rarely see in my backyard, were numerous on this patch of New England Aster and were collecting both nectar and pollen.  This bee already has good-sized pollen baskets on its rear legs.

Common eastern bumblebees (center) were probably the most common bee on these flowers, but shared the resources with at least five other species of bees and a couple of species of Syrphid flies (hoverflies), seen in top left.

Both a large bodied (about as big as a honeybee) and a smaller bodied hoverfly worked the flowers. These are bee mimics, presumably avoiding predation by pretending to be fearsome stingers.  However, they have no weapon defense except their coloration, and have only one pair of wings (unlike bees and wasps which have two pair) with which they hover over and between flowers.

A smaller green sweat bee is unperturbed by the far larger bumblebee foraging next to it. There isn’t really much competition when there are so many flowers in this patch of aster.

I assume bees can smell or taste the presence of nectar in a particular flower, so some of the flowers got worked over very intensively by some bees that probed their tongues into every recess in the collection of disk florets in the orange center of the flower.

Honeybees and bumblebees are particularly good dispersers of flower pollen, as it easily attaches to the spines on their legs or hairs on their heads and bodies, as seen in the photo above.  The smooth exoskeletons of the body and legs of the hoverflies and sweat bees make them far less effective in transferring pollen from one plant to another.

If you live east of the Rocky Mountains where New England Aster grows, you might have noticed the profusion of aster flowers that has suddenly occurred over the past couple of weeks.  I assume synchronous blooming like this over widespread areas is probably triggered by the changing daylength, and is advantageous in pulling in large number of pollinators to maximize pollination and seedset in these asters.

Getting into focus

Last year’s big Christmas present was a new macro lens, which I didn’t get around to using until spring, because frankly it was too cold to try macrophotography outdoors last winter.  Apparently, I didn’t use it very much even then, because it was much easier to select the top ten “small things” photos than it was for the birds. But here they are — the top 10 macro shots of 2014, chosen for their color, variety, and potential biological interest.

An Orange Bluet male on a smooth, contrasting background of green.  I never saw one like this again, after I took this photo.

The contrast of black in the Black Swallowtail on the white of the Dutchman’s Breeches was the basis for this choice.  Finding nectar in early spring can be a challenge for early emerging butterflies.

In contrast to the shot above, the Tiger Swallowtail in a sea of summer wildflowers had numerous choices from a variety in the wildflower garden.

It’s difficult to choose such a noxious pest insect like the Squash Borer Moth for this collection, but it is a colorful insect caught in mid-flight (in focus!)

Another moth, rarely seen at rest — the Hummingbird Clearwing Moth (Hemaris thysbe).

One of several species of meadowhawks difficult to tell apart in their juvenile stages. They were very abundant in the wildflower garden this summer, hopefully gobbling up the many mosquitoes there.

I never realized what a popular flower Spiderwort is to insects. The Green Sweatbees, hoverflies, and bumblebees stocked up on its pollen in early spring.

Another rare visitor to the back yard (well, really a neighbor’s front yard) was this Leadplant Flower Moth, a specialist on said plant.  Read more about it here.

If you have ever been bitten by a 2-inch horsefly, here’s why it hurt. Those are a couple of shearing scissors up front in its mouthparts.

And lastly, the colorful Milkweed leaf beetles attempting to mate on a milkweed leaf. It’s more of a humorous shot really, since this male tried every which way to get into position.

Pollen collectors

In between rain storms, the pollinators are hard at work in the garden collecting pollen for their nests.  Several species were visiting the Spiderwort, which provides only pollen but no nectar for its pollinators.

Tri-petaled purple flowers of the Spiderwort open one at a time in the early morning, but close in the mid-day heat.

Bright yellow pollen sacs on the tips of the anthers stick up above the petal surface. The solitary stigma (smaller yellow tipped structure at 3 o’clock on the right) will be brushed with the pollen from adjacent flowers as pollinators crawl around the pollen sacs.

Bumblebees (Bombus spp) are so heavy, especially this one loaded with huge orange pollen baskets on its hind legs, that they pull the anthers down when they land on them.  They gather the anthers toward their mandibular jaws with their forelegs to harvest the pollen.

Green sweat bees (Agapostemon spp.) were a little more deliberate in their pollen collection than the rapidly moving bumblebees which spent only milliseconds on one flower.  These are short-tongued bees, dependent on pollen to provision larvae in their ground nests, since they can’t reach the nectar supply in most flowers.

Small syrphid flies (Toxomerus spp) also eat pollen, but they are ineffective pollinators for this flower because their bodies are too small to contact the protruding stigma while foraging on the pollen sacs.  The stigma is on the lower right of the fly’s body at 5 o’clock.

Thanks to the many species of pollinators working these flowers in previous years, there are now about 50 spiderwort plants spread all over the garden from the original 6 that I planted.