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. These posts share how we found the land and how we made the transition from city-dwellers to country folk.
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.
One of the most important features of Timberhill is that it isn’t in the middle of a corn desert. Although there are some crop fields on adjacent properties all owned by non-residents and are managed for deer and turkey hunting. This month Bill and I have been made several trips to the property east of Brush Creek, our east property line. A typical southern Iowa landscape of rolling hills and valleys that branch off the ridgeline it is similar to our West Creek unit. Both have bottom fields along a creek, prairie remnants, and were formerly pastures.
We surveyed the butterflies in a 30 acre former pasture that has been in CRP for over 10 years. The ridgetop meadow is bordered by Pony Farm Road on the north and east and woodland on the west. Large clumps of crownvetch dominate the ridgetop but branches that extend off the ridgeline into the surrounding woodland are scattered with conservative native plants including purple prairie clover, rattlesnake master, and panicled tick trefoil. Sedges, Indian grass, and winged loosestrife are also abundant there.
For butterfly observation there is abundant common mountain mint, wild bergamot, dogbane, and common milkweed, all preferred nectar sources. . There are even a few Sullivan’s milkweed plants just off Pony Farm Road. (an uncommon milkweed). We have observed all the common species, the Cabbage whites, sulphurs, Pearl crescents, and Great spangled fritillaries. Most abundant are the Great spangled fritillaries which is also true of Timberhill. We have also seen a Tiger swallowtail feeding on Sullivan’s milkweed. So far Dun skippers are only skippers we found. I saw a coral hairstreak, not a common species, perched on shingle oak. Best of all was a Juniper hairstreak, a species I have never seen at Timberhll, feeding on mountain mint near a red cedar. (We cut down all the red cedar, its larval food plant on our property.)
However, so far we have not found any Regal fritillaries, Edward’s hairstreaks, or Dion skippers, three species which we regularly see in the West Creek unit. Regal fritillaries are strongly habitat dependant limited to native prairie remnants. Their larvae overwinter in leaf litter. We don’t know whether they overwinter on our property, the adjacent cornfield, or small prairie remnant heavily infested with red cedar to the north. The Dion skipper is restricted to wetlands and usually found in northern Iowa. The Timberhill population is the only record of this species in Decatur County. Edward’s hairstreaks are confined to low growth scrub oak habitats with nearby ant colonies (Formica integra). Larvae are tended and protected by the ants in exchange for their sweet secretions.* This species is concentrated on a hillside with scrub shingle oak and native prairie.
Despite our prescribed fires population of these species has increased in the West Creek unit. Last month I saw five Edward’s hairstreaks in an hour. I usually see a Regal fritillary each visit. The Dion skipper is now regularly encountered in the sedge meadow that borders the wetland.
*Rick Cech and Guy Tudor. 2005. Butterflies of the East Coast. Princeton: Princeton University Press.
The best moth collecting usually coincides with the dark of the moon. Fortunately we had a few nights shortly after the new moon June 16 when rain did not threaten and we could set up our moth lighting in the East Savanna and on adjacent unmanaged property. On the adjacent property we used a moth trap constructed at the local welding shop. It consists of a funnel in a hardware cloth cage with a removable bottom. A black light fluorescent tube is suspended from a plant hanger attached to hoops on top of the cage Moths attracted to the black light fall through the funnel into the cage. they usually perch to the sides of the cage. The next morning we list and inventory the specimens. The specimens are then released.
The site most similar to conditions in the East Savanna is a wide opening in the oak and hickory woodland south of our property line. The first night the trap filled with geometer and three blinded sphinx moths. The second night there was more diversity, In addition to the geometer moths we collected two Luna moths, a Little virgin tiger moth (county record), 3 yellow underwings, a Small eyed sphinx (2014 county record), an Io moth (2014 county record), 2 more Blinded sphinx (county record), and one Giant leopard moth (2014 county record).
We collected the same species in East Savanna. In addition a luna moth, a twin spotted sphinx, two Imperial moths, several Isabella tiger moths, and a polyphemus moth were also attracted to that black light. And there was much more diversity with many small specimens that I did not identify.
Two species are of particular note: the Io and Imperial moths. In 2014 the Io moths I collected were the only collections of that species submitted to the Insects of Iowa website. So far this year we have attracted four specimens at Timberhill. This is a habitat sensitive species since the cocoons overwinter in leaf duff, under dry logs, or on hickory leaves. Finding them here indicates that the cocoons survive our annual dormant season prescribed burns.
The Imperial moth is another species in decline. Although it used to be common throughout its historical North American range it is in decline throughout the northeastern US. In 2014 the Insects of Iowa site listed only four sightings, two of which were in Decatur County (Lamoni and Timberhill). Imperial moth cocoons overwinter in underground burrows.
We will need to accumulate much more collection data to determine how our woodland management is impacting moth diversity. But the fact that we are finding rare habitat sensitive species at Timberhill is a good sign.
Michael M. Collins and Robert D. Weast. 1961. Wild Silk Moths of the United States. Cedar Rapids, IA: Collins Radio Company