Wednesday, May 25, 2011

Shaw Nature Reserve

If I were going to film The Lord of the Rings, I'd start at Shaw Nature Reserve, in Gray Summit, Missouri. For Lothlórien, the enchanted forest where forest elves live in fantastic tree houses, we'd take cameras down the Wildflower Trail. Oaks and hickories give way to pawpaws and ancient sycamores as the trail drops to the Meramec River. Prothonotary Warbler sings in the background. Whole hillsides are covered with dwarf crested iris (Iris cristata). Picture Orlando Bloom running through this scene, bow in hand. Are ya feelin' it?

The St. Louis Chapter of the North American Butterfly Association (NABA) held a butterfly count here on May 22. I arrived about an hour early to do a little birding. (Birders get up earlier than butterfliers.) Along the border of the woods, a Wood Thrush sang its haunting song. In the meadows I heard several Prairie Warblers, while Barn Swallows and Tree Swallows glided over the lake.

Juniper Hairstreak, photo by Jeannie Moe (used with permission)
We began our count on the well-named Bluff Overlook Trail, with great views of the landscape and a the opportunity to occasionally look birds in the eye as they hunt for caterpillars in the treetops. We passed dolomite glades where coneflowers were just beginning to bloom. On a coreopsis (Coreopsis lanceolata), Jeannie found our best butterfly of the day: Juniper Hairstreak.

Yvonne and her group spotted an amazing sight: a Polyphemus Moth was just emerging from its cocoon. Its body and legs appear swollen as it pumps fluid into its wings to expand them. This creature is as fantastic as any in Middle Earth.

Polyphemus Moth, photo by Yvonne Homeyer (used with permission)

Friday, May 13, 2011

Pawpaws and Pollinators

With large, tropical-looking leaves, and a dark, mysterious flower, the Pawpaw (Asimina triloba) is the kind of tree Tennessee Williams would have planted next to the magnolias, if he had been into gardening. The blooms look like a dark red bell hanging below the branch. The dark color makes them less than showy than a Flowering Dogwood, but attractive, especially when backlit by the afternoon sun. It’s the classic Missouri bottomland tree, but when I mention that it’s pollinated by flies because the bloom looks like roadkilll—well, it turns people off.

I wrote about Pawpaw’s relationships with butterflies and moths last July. Still, people imagine, as I did, a Pawpaw in bloom, swarming with big hairy flies and a putrid odor wafting on the wind. Nothing could be farther from the truth. I took the photo above on April 20, but when I downloaded it from the camera and the photo filled the screen, I saw the flies for the first time. The flower was about 2 inches across at its widest point. I would have had to wear my reading glasses to see the flies.

Pawpaws don’t make it easy on a pollinator. To bear fruit, the bloom needs pollen from an unrelated Pawpaw. What’s more, process depends on a pollinator that is believed to be inefficient, sloppy, and promiscuous—that is, it’s like to visit many things other than a bloom of a Pawpaw.
Gosh, the flower looks alarmingly fleshy in this extreme crop! Those flies look pretty scary too, but the red eyes in the photo are caused by the flash.
Ted MacRae at Beetles in the Bush wrote about Pawpaws last May. In comments,  James Trager, entomologist and restoration biologist at Shaw Nature Reserve, wrote that the tree is likely pollinated by fungus gnats. Fungus gnats are important pollinators, but the critters in my photo don’t have the comparatively long legs I associate with gnats.

I posted my photo on Bug Guide to ask for some ID help.  One person suggested that they could be lesser dung flies. I estimated that the fly was 2 mm long or less—about the right size for dung fly family (Sphaeroceridae).  The Wikipedia article states that dung fly larvae eat fungus or bacteria on rotting vegetation. Another user on Bug Guide suggested that because the blossoms are stinky, they must be some type of carrion fly. That brings us to the next question, what does a Pawpaw blossom smell like? 

I headed out to the tree again and got up close and personal with the flower. It didn’t smell like roadkill, or dung—it had just the faintest odor of yeast. I could only detect the scent when my nose touched the bloom. Of course, yeast is a fungus, so fungus gnats and lots of other decomposers should find the fragrance attractive. But why be shy about the aroma if the plant really wants to be pollinated? 

I have some ideas about that. First, just because the odor is hard for me to detect doesn’t mean that it’s hard for insects to find. Although I had been thinking that there was only one specialized organism that pollinated Pawpaws, I found this statement in a 2001 article in Ecology and Society by Carol Ann Kearns:  "Many species of flies are generalists that visit multiple plant species." There are probably a number of different fly families that offer their pollination services to Pawpaw, though the flies don't seem to get any reward. 

Second, it's possible Pawpaw is a bit conflicted about this whole fruiting process. According to California Rare Fruit Growers, because each bloom has more than one ovary, "a single flower can produce multiple fruits." Add to that this advice to growers resorting to hand pollination, from a 1990 article from 
Kentucky State University Cooperative Extension Program: "
Do not overburden the tree with fruit, as this will stress the tree, resulting in smaller than normal fruit, and may cause limbs to break under excessive weight." Perhaps half-heartedly attracting an inefficient pollinator is Pawpaw's adaptation to it's own heavy fruit.

Monday, May 9, 2011

Fire Pink

Besides having a stunning red flower, Fire Pink (Silene virginica) attracts hummingbirds, and I'm all about that! So I made a number of clumsy attempts to grow it in my garden and always failed, until last year. That's when I decided to get serious about imitating the habitat where I first found it: on a dry, rocky, west-facing hillside in Jefferson County, Missouri.

A glade garden may seem an odd choice in an east-facing, suburban front yard, but that's where I have a slope and the greatest hours of sunlight. I started by removing the Bermuda grass, and some of the dry, clay soil. I replaced it with crushed limestone, and topped that with the rocks. I had to purchase rocks that I could lift, so I looked for ones that could fit together to give the impression of a rock shelf. Then I tamped and pounded till they seemed stable. Once you install an artificial limestone/dolomite ledge, you're pretty well committed, so I really needed a success.

I had a moment of panic when I reread Kurz' description of the typical habitat in Ozark Wildflowers: "wooded slopes in sandstone, chert, or igneous soils." That suggested acid soil, not clay and limestone. As they say though, the plants don't read the books, and the Silene gods smiled on me. My Fire Pink bloomed well last year and returned for an even stronger show this year. Dan Tenaglia's website,, has really great photos of this plant in the wild, and the rocks in his photo look suspiciously like limestone/dolomite.

The stem and calyx of Fire Pink or Catchfly are sticky. John Hilty's website, Illinois Wildflowers (which I talked about in January 2011), says that the purpose of that sticky substance is to discourage ants from "stealing" the nectar. An animal "steals" nectar when it takes nectar without pollinating the flower. Hilty says however that little is known about Fire Pink's pollinators, although is is presumed to be hummingbirds. Even though I've only seen a hummer at the blooms once, I don't have any doubt Silene is a hummingbird plant.

Sunday, May 1, 2011

Victoria Glades

If I had to pick a favorite habitat, it would be glades. Open sky, tough plants, rocks that invite you to sit and look, that's what I'm talkin' about! To officially qualify as a glade, the area must have all or most of these characteristics:

  • thin, rocky soils
  • exposed bedrock
  • steep slope
  • facing south, west, or southwest
  • dry, fast draining soils
  • fire adapted plants
  • scarcity of trees

Spring is busy for gardeners with binoculars, but I decided to make time for "Missouri's Glades," a continuing education class at St. Louis Community College, sponsored by Missouri Native Plant Society (MONPS), and taught by their past-president, Rex Hill. Our first field trip was to a dolomite glade less than an hour from me,  Victoria Glades in Jefferson County. One portion of the glades is managed by The Nature Conservancy, the other by Missouri Dept. of Conservation.

Let's get right to the amazing plants and animals: I have never seen so much Indian Paintbrush (Castilleja coccinea)! The whole hillside had a reddish cast. Alongside the paintbrush, Fremont's Leather Flower (Clematis fremontii) bloomed. This is a non-climbing clematis, rare and protected in Missouri. I have never seen it in  bloom before.

A female broad-headed skink warms in the sun from a tree cavity on the edge of the glade.
Down by the creek, the Louisiana Waterthrush sang his beautiful, slurred complex song. Up in the glades, Prairie Warblers sang from thickets of fragrant sumac (Rhus aromatica). Eventually, one danced to the edge and gave us great views. Blue-winged warbler, another species that likes open or shrubby habitat, popped up to the top of a tree, threw back his little yellow head, wheezing his sleepy, "Beee-buzzzzz."

In spite of strong breezes, we saw butterflies too.We watched a very faded, transparent Monarch nectaring on leather flower. There were Eastern Tailed Blues on False Toadflax, and we saw several Pearl Crescents.  I just managed to get a poor photo of a dark butterfly, which I think was a lifer for me, a Dusted Skipper!

One of the group found a Wild Turkey egg in the dry grass. A good part of the egg was missing, and as we look inside, we could see a large beetle that apparently was eating what was left of the yolk, or possibly, was eating whatever was eating the yolk. After following Beetles in the Bush and taking my first tentative steps toward appreciating insects, I was excited that I identified it as a carrion beetle, Necrophila americana.

John managed to find us a striped bark scorpion, a Western Slimy Salamander,  and this little dandy, an Eastern Hog-nosed Snake. Non-venomous hog-nosed snakes are the entertainers of the reptile world. A hog-nose can play possum, rolling over belly-up leaving its tongue out. When being "dead" doesn't seem the best defense, it will try to bluff its way out of the jam. It can pull its head and front portion upright, spreading its neck in a thoroughly convincing imitation of a cobra; when I happened to come upon one of these tricksters, it made my hair stand on end! Pat, who volunteers at a St. Louis County conservation area, told me that they had reports of 3 cobras just that week!

I took about 100 photos--seriously. I shared a few of them here.