I am Sibylla Brown. I was born in Germany in 1940. In 1946 my father, a German Operation Overcast scientist, was brought to the U.S. My family followed him to the U.S. in 1947, settling in Cedar Rapids Iowa in 1950. I married my husband, Bill in 1962. Bill practiced dentistry in Des Moines for over 40 years. In 1993 we sold our house in Des Moines and moved to a 200 acre farm in Decatur County, Iowa. Except for a small vineyard we had no plans to farm our land. But we did want to take care of it, particularly the overgrown oak and hickory woodlands. We began timber stand improvement in 1993. When we learned our land was actually a rare oak savanna remnant we implemented prescribed fire. I keep monthly journals to record our activities and observations. These posts summarize them.
The first week of October we decided to try moth baiting in the hickory grove in our West 40 unit. This woodland was a horse pasture until 1938 when the owners bought a tractor and no longer needed horses to pull their plow. After grazing ceased the meadow grew up into a shagbark hickory (Carya ovata) woodland. When we purchased it in 2001 is was heavily overstocked. We thinned the woodland in 2002, felling over 50% of the trees. A groundcover of wildflowers, grasses, and sedges is now well established under the canopy.
For moth bait we mixed stale beer, molasses, brown sugar, overripe bananas, and yeast in a bucket and let it ferment overnight. Shortly before dusk the next day we walked along the trail that winds through the woodland, first west then south where it separates a native prairie remnant from the shagbark hickory. Carrying the bucket of moth bait we brushed the intoxicating syrup on the shags of trees closest to the trail. I had hoped to attract some underwing moths to the bait. When I checked the baited trees before sunrise the next morning I was disappointed – no underwings. The only moth of interest was a stem borer which I collected.
It was not a species I had collected before. Searching my field guides I tentatively identified as P. birdi, Umbellifer stem borer. (Water hemlock, its larval food source, is found in the nearby prairie remnant.) For confirmation I asked my friend who knows this genus well. His first reaction was,
“A Papaipema at bait–I wouldn’t have expected that! I’ve never heard of them coming to bait.” He asked me to send him a photograph. His response was a big surprise. “I think this is a MUCH better moth than birdi. I think it is marginidens but I will see if I can get additional opinions. I believe there is a single Iowa record from a savannah type oak woodland remnant in Story County.” The specimen I collected was in fact confirmed to be Papaipema marginidens, Brick-red borer moth. A nice find.
When we began moth lighting I was overwhelmed by the number and diversity of specimens. I was too inexperienced to identify all of them. Instead I began with the easy ones, the giant silkworm and sphinx moths. Now I realize I should have been focusing on the underwing (Catocala) moths. Catocala forewing patterns resemble tree bark and hindwings are either all black or brightly colored with black bands. Over 100 species are found in North America. Since the larvae of many species of this large group feed on trees found at Timberhill and in the adjacent unmanaged woodlands we should be able to find 40 to 50 species. (The larvae of 20 species feed on hickory leaves.) So far I’ve only collected thirteen oak, hickory, plum, and willow feeders.
Butterflies were on wing through the end of October. Most abundant were the anglewings and Buckeyes. Gray commas and Question marks (anglewings) settled on the baited shagbark hickory by day. For several days after baiting the trees we saw 4 to 5 specimens on each trunk. These were the second brood that will overwinter as adult butterflies under loose bark, openings in fallen logs, and hollow trees.
We saw Buckeyes daily in West Creek. All were fresh looking specimens that had bred on the abundant slender false foxgloves in this unit. Common checkered skippers were also seen skipping ahead of us on the trails when we took our daily walks.
At the end of the month we were pleased to see Turkey vultures still soaring overhead. They are usually the last migratory species to head south for winter. As long they are flying winter will wait.
(Besides Jim Durbins’s Insects of Iowa site there are two excellent resources available for more information: Theodore Sargent’s Legion of Night portions of which are available online and Owlet Caterpillars of Eastern North America by Wagner. Schweitzer, Sullivan, and Reardon.)
I am continually in awe of nature’s power to restore itself. A prime example is the old cornfield in our West Creek unit. It was farmed continuously from 1937 until 2005 when Bill and I took it out of production. Each fall for the next three years we seeded it with big bluestem and Indian grass that we had harvested from the adjacent prairie remnant. We didn’t plant or seed anything else. We burned each field annually during the dormant season. Now a colony of Henslow’s sparrows nests in the tall grass each summer.
When I surveyed the field last month I was surprised by how diverse it had become. Slender and eared false foxglove have spread throughout the field contrasting with the white, blue, and purple asters. Scattered throughout the field were clumps of bottle gentian, an uncommon plant. Best of all I counted 27 great plains ladies’s tresses orchids. The late bloom and strong sweet fragrance of coumarin from the spiral of white flowers confirmed that they were Spiranthes magnicamporum and not Spiranthes cernua.
Hearing a bumblebee I turned and watched it land on one of the closed gentian blossoms. It quickly separated the petals and disappeared inside to gather pollen. Then he reappeared and moved on to the next blossom. Buckeye butterflies were nectaring on showy goldenrod. I even found a Buckeye caterpillar feeding on a slender false foxglove.
Fritillary butterflies were still flying in late September. The last Great spangled fritillary I saw on September 23 was pretty beat up with hardly anything left of his hindwings. However, the Meadow and Variegated fritillaries still looked reasonably fresh. Eastern commas were also flying at the end of September and Black swallowtails were on the tall thistles. (In the vegetable garden black swallowtail caterpillars were devouring the parsley and dill.)
The last week of September we set the moth trap on the terrace west of the house and caught a five spotted hawk moth and two underwing species: Robinson’s underwing (Catocala robinsonii) and Youthful underwing (Catocala subnata). On Robinson’s the forewing is pale gray and hindwing is black with a narrow white fringe. The underside is boldly patterned with prominent black and white bands. The more colorful Youthfull underwing has golden yellow banded hindwings that contrast sharply with the pale gray forewings.
Fall mushroom season began on September 29 when I collected the first wax cap, a Hygrophorus subsalmonius. It is easily identified by its viscid orange cap and white gills. Purple gilled Laccaria ochropurpurea was fruiting in clumps throughout the East Savanna. Russulas (brittle cap) mushrooms were also abundant. Chanterelle season continued into September. I collected the last fresh specimen on September 15. But I was disappointed by the dearth of King boletes, a choice edible that usually fruits in the East Savanna in September.
I know that I shouldn’t be planting non-native species. Not only can they become invasive but butterfly larvae will only eat native plants. But last spring I was desperate for some color in a rain garden east of the house. I wasn’t willing to wait for plants from seed collected on my property. I wanted instant color. So I bought three hybrid butterfly milkweeds at a Des Moines greenhouse. Besides, with all the native milkweeds on our property what harm could I do? There are abundant stands of common milkweed in disturbed areas, purple milkweed and whorled milkweed at the woodland borders, swamp milkweed in the wetlands and butterfly, Sullivan’s, and tall green milkweed in the prairie remnants on our property. Seven species in all. That’s plenty of food for the Monarchs. So what if I plant three hybrid specimens? I didn’t need more Monarch food. I wanted milkweed bloom that I could see from the kitchen window this year.
Four weeks ago I was completely surprised to find three Monarch larvae munching on the hybrid plants. The next week I wanted to show them to a friend, but they had disappeared. The only evidence of their existence was frass left behind on the milkweed leaves. My friend who is an excellent amateur lepidopterist told me that the size of the frass indicated that the caterpillars had probably left the plants in search of a place to pupate. I hoped that he was right and that the birds at the nearby bird feeder weren’t responsible for their disappearance.
A couple days later Bill was turning on the faucet to water the potted rosemary outside our front door when I heard him say, “There’s a chrysalis here.” I finished watering the rosemary and walked to the faucet to look at what Bill had found. And there it was: a Monarch chrysalis attached to the cypress trim on the house exterior. From the rain garden the caterpillar had crawled across 16 feet of lawn, then across the river rock that borders the house and up 4 feet of stucco exterior to attach to the wooden trim.
And there are still Monarch caterpillars munching on the hybrid milkweed. Two days ago Bill and I counted 7 specimens. I’m watching caterpillars consume hybrid swamp milkweed instead of butterflies nectaring on the blossoms.
Ever since Bill and I began restoring the native plants on our property our goal has been to restore an abundance of healthy forbs and graminoids. Now I’m looking for plants with wilted tips, discolored leaves, and stunted, bent or broken stems with bore holes. Why? I’m looking for evidence of Papaipema, stem borer moths. Although some are generalists most Papaipema are very host specific. Because of their specialized habitat “a number of species appear to be slipping to extinction.”* The Rattlesnake master borer, for example, is critically imperiled. It is completely dependent on undisturbed prairies with abundant Rattlesnake master. Rattlesnake master grows in 26 states but its stem borer is found in only five states (IL, KY, NC, OK, AR).
Stem borer larvae bore within the stems, roots, or rhizomes of various forbs. One or two holes often with an accumulation of frass at the base indicate presence of a Papaipema larva. A few species’ larvae can be found in galls near the base of the plants. Adults fly from mid-August and until late October or until temperatures drop below 50 degrees Fahrenheit. They deposit eggs near or on larval food plants. After hatching the following spring the larvae bore into a plant stem and settle in the roots or the stalk. Common food plants include aster, ironweed, Joe-pye weed, mayapple, ragweed, thistle, burdock, and bracken and sensitive fern.
Last month a friend showed Bill and me how to find Papaipema larvae. Closely inspecting the stalk of an Indian plantain with discolored foliage he found a hole surrounded by frass. Then he cut away a section of the stalk above the hole and peeled it away from the stem borer larva. Many Papaipema larvae are very similar and difficult to identify to species. However they can be reared to maturity on carrots, potatoes, or sweet potatoes. Our friend placed the specimen in a ziplock bag with some moist plant material. At home he will feed the caterpillar to a carrot and identify the species after eclosure.
*David A Wagner, Dale F. Schweitzer, J. Bolling Sullivan, & Richard C. Reardon. 2011. Owlet Caterpillars of Eastern North America. Princeton: Princeton University Press. Page 410.
Dept. of the Interior, Fish and Wildlife Service. August 14, 2013. “Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to List the Rattlesnake-Master Borer Moth (Papaipema eryngii) as an Endangered or Threatened Species.” Federal Register volume 78, Number 157.
In the past couple weeks Bill and I made several butterfly forays to the property south of our fence line. There we followed the wide trail that winds through oak and hickory woodlands to a constructed wetland along the Weldon River bottom. We call the trail Butterfly Alley because this is where we always see the first mourning cloak of the season and is a good spot to observe giant and tiger swallowtails as they glide among the treetops. We’ve also seen rare species such as the Zabulon skipper there. Mountain mint and bergamot, two good nectar sources, are currently blooming on the trail and river bottom. Last week we also found a butterfly milkweed blooming at the woodland edge.
Besides the common summer butterfly species we saw a Horace’s duskywing feeding on mountain mint last week. According to Butterflies of Iowa this duskywing is an uncommon breeding resident, “scattered and rare throughout the state.” (Bill and I also see it at Timberhill every year.) So far the only other skippers we’ve observed on this adjacent property have been Silver spotted and Dun skippers. (At Timberhill we’ve identified 18 skipper species including the Byssus skipper, a rare breeding resident “restricted to native prairies.”)
For us time spent on unmanaged adjacent land is disheartening. Conservative native plants such violet bush clover are just hanging on in sunny openings. The woodlands abound in mature oak and hickory but are so overgrown that little sunlight penetrates the canopy. We see so much potential here. Yet these landowners are like parasites on the land caring only about how many big bucks and turkey gobblers they can shoot. They have complained about the dwindling deer and wild turkey population on their property. They don’t understand that everything is connected. That the game they are seeking thrives only in a diverse habitat. Just as the plants are winking out and sunlight is banned from the woodland the big bucks and turkey gobblers will find better habitat elsewhere.
After our last foray Bill and I decided to raise our spirits by watching butterflies in our south field which we began restoring in 1993. It’s just three acres but the abundance of bergamot, mountain mint, and common and marsh milkweed attract many butterflies. There we watched four Monarch butterflies dance among the swamp milkweeds. They glided from one bloom to another, moved off stage to sample the bergamot and then rejoined the corps on center stage. Occasionally two of them circled above the flowers in a pas de deux. Background music was provided by an Indigo Bunting singing from a nearby shrub. Watching the performance one would never know that Monarchs are in serious decline. They are thriving here.
I was stimulated to write this series because Bill and I have been told that “insects, eggs, or immature stages within the plants and the thatch cannot survive your burn regimen.” I was hoping to convince the doubters that invertebrate diversity is increasing not decreasing as a result of our management. Watching the Monarch ballet I realized that what others think of our fire management doesn’t really matter. We know it is working.