Wednesday, May 26, 2010

Bearberry-eating elfin

Strolling the trails and beaches of the Lake Huron shoreline in Presque Isle County, Michigan is an excercise in constant distraction. There are all manner of birds, and one must generally keep their eyes elevated to spot those. But looking up is tough when plants such as Yellow Lady's-slippers, Cypripedium parviflorum, are quite literally roadside "weeds" in places. The individual in this photo is a gem of an orchid; an unusual double-flowered form.

Coming from Columbus, Ohio - the land of invasive bush honeysuckles - it was nice to see some of the native honeysuckles. This is Wild Honeysuckle, Lonicera dioica, a plant that is becoming scarce down here but remains common up there. Most of the flowers that I saw were this striking deep red-orange color; most that I see in Ohio trend towards yellowish.

Brilliant yellow-orange flowers of Plains Puccoon, Lithospermum caroliniense, stand in stark contrast to the white sandy dunes of the Huron shore. The low shrub in the back left is Ground Juniper, Juniperus communis var. depressa. And the darker low-growing mat to the right of that is a most interesting little heath - Bearberry, Arctostaphylos uva-ursi.

Bearberry is a beautiful little shrublet that is very common in sandy ground throughout the northern Great Lakes and far beyond. Ohio lies at the southernmost limits of its range, and there are but two old records in our state, along the shores of Lake Erie.

The tiny flowers dangle in pendant clusters, and are urceolate or urn-shaped. Like tiny ewers with mouth tinged pink, they demand a close inspection once noticed.

The evergreen leaves are thick and coriaceous - leathery - and it's hard to see how a caterpillar could or would chomp into them. But at least one noteworthy cylindrical bag of goo does indeed make Bearberry its meal of choice.

I was excited to see many of these quarter-sized butterflies frequenting gravelly openings near Bearberry patches, and upon my first good look at one, saw that they were elfins. But not an elfin that I had ever seen. It didn't take too long to ferret out the name: Hoary Elfin, Callophrys polios. Small wonder we were in elfin city - these mites require Bearberry as a host plant, along with another heath that was very common, Trailing Arbutus, Epigaea repens. Good thing their caterpillars have evolved to eat these tough heaths, and thus transform into the elfins that add a real dose of lepidopteran excitement to the sandy plains.

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3 comments:

Anonymous said...

I thought John Pogacnik found Bearberry 5 or 6 years ago along the Lake Erie shoreline.
Brian

Janet Creamer said...

Just beautiful, Jim!

Jim McCormac said...

Yes, you're right, Brian - I forgot about that. If memory serves, the plant didn't appear to persist and John may have only seen it one year, but if he sees these and I'm wrong perhaps he can set the record straight.

Jim