Resilience in a Roadside

A Few Goldenrods, a Swarm of Insects

Yesterday (August 13, 2025), I drove some back roads on the way from the Des Moines area to Grinnell. Often I do this, despite the extra gas it uses, to see what birds sit on the utility poles and wires, spot plants and plant populations in the roadways and adjacent riparian areas, and collect a few data points. In addition, when the native plant species are in seed, I stop to collect some seed to scatter elsewhere.

This activity has become a near-habit in the past ten-plus years, as my awareness of indigenous plant species has grown. That happened because I contracted with three counties over several years to conduct roadside vegetation surveys under the Iowa Roadside Vegetation Management program. Each county can choose to participate, and if it does, it receives budget for purchase of seed and equipment along with dollars for an initial survey. In my case the counties of Marion, Scott, and Hardin (in chronological sequence) hired me to drive their secondary roads for documentation of noxious weeds, obstructed visibility, erosion, existing prairie and wetland plantings, and locations for future plantings.

In Marion County, my expectations were low. Most roadways cut through agricultural land where herbicides have been used for decades, and remnant plant populations might not exist. On the other hand, the county’s Secondary Roads Department had participated in the planting program for several years, so observation of those and additional data on the banks and ditches were needed.

By summer’s end, 860 miles of county roads had been driven, with data recorded by quarter-mile segments. With only a paper transportation map that located past prairie plantings, I depended on fencelines at half- and quarter-mile increments to determine the road segments. Often the quarter-mile fencerows were present, but sometimes I needed to guess; the half-mile boundaries almost always were present. Mile-long road segments usually were marked by a section road in the gridded Public Land Survey System, and the transportation map showed the townships (36 mile-square sections), 640-acre (usually) sections, and some landmarks.

What astounded me at the end was documentation of over 200 species of original plants, most of which did not come from the prairie planting program, and locations of small remnant prairie or wetland with as many as thirty species in each, or as as few as five or six. When I turned in the data, I made sure to inform the roadside manager of the presence of these remnants so that they could be preserved and perhaps managed.

In the bigger picture, after the surveys of the three counties (around 2,400 miles of roadway), those roadsides held significant populations of common and scarce indigenous plants, despite the assaults of human disturbance: construction of the roads themselves, chemical-heavy crop farming across the fence, thick populations of Eurasian pasture plants abutting the bank, and mowing for hay. This last practice is permissible under Iowa law, although the last few years have seen the rights-of-way cut well before the legal first day of July 15 or planted to turfgrass to make farmsteads and test plots of corn and soybeans look “pretty.”

Let me come back to yesterday, August 13. On a gravel road in Jasper County, I noticed a few goldenrod stems along the road as I drove past, with a swarm of insects on the blossoms. I stopped and walked back with my camera and 180-mm lens. Despite gravel dust, a bean field, and other reasons why the situation shouldn’t exist, I documented these insects on the goldenrod or on nearby red clover:

• Clouded Sulphur Butterfly (Colias philodice), one of two common sulphurs in summer and early autumn; the other is the Orange Sulphur (Colias eurytheme). Two other sulphurs occur occasionally in very late summer to autumn.

• Five-Banded Thynnid Wasp (Myzinum quinquecinctum), one of numerous wasps that feed on nectar and help pollinate flowers.

• Pennsylvania Leatherwing (Chauliognathus pensylvanicus), very common by late summer and often on goldenrod. They are active pollinators, although they lack the hairiness of bees and flower flies.

• Sweat Bee (Agapostemon sp.), two females (female shown here)

• Augochlorine Sweat Bee (Augochlora pura), a small, metallic green bee that can be quite common. Many important native bees are small, from about 4 mm (1/4 inch) to 15 mm (5/8ths inch), and they are overlooked because of their size.

• Common Eastern Bumble Bee (Bombus impatiens). This male was about 10 mm or 7/16ths inch. Each species of bumble bee in Iowa has its own season, with some visiting spring flowers, some summer to autumn blossoms, and a few occurring all season. This species is widespread, making it an important pollinator of many plants.

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• Grass-Carrying Wasp (Isodontia sp.), maybe a Mexican Grass-Carrying Wasp (Isodontia Mexicana). It helps prove the point about our ignorance of many of the insects around us and their ecological roles. We have little idea about what we destroy. Yet here it is, visiting goldenrod blossoms in the midst of intensively farmed land.

• Tachinid fly (genus Cylindromyia). Take some time to appreciate the colors and patterns in the wings and abdomen. Not all flies are “just flies” or pests. These parasitize some other insects, including pest species. The adults feed on nectar.

In addition, two introduced and pervasive insect pests were present:

· Japanese Beetle (Popilia japonica)

· Northern Corn Rootworm Beetle (Diabrotica barberi)

I’ve offed many Japanese Beetles this year, knowing that any difference I make may be for a few specific plants at one location, and nothing more. My backyard red raspberries and the New England Asters in a small prairie plot in the front yard have already suffered a lot of leaf damage, but my effort may have prevented a lot more. A past client of mine installed a few dozen pheromone-based traps on her 240 acres of mostly restored prairie and wildlife habitat, only to have the traps fill to capacity in one or two hours. Did that make a dent in the long run? It’s doubtful.

The lesson here is that our roadsides are and can be vital supports for biodiversity – the “web of life.” More than that, our animals and plants demonstrate tremendous resilience, and a few stems of goldenrod in a Jasper County ditch have a surprising array of insect life. Not much effort would be needed to increase that resilience – mainly just a few seeds, some attention, and greater awareness. Botanists talk about “plant blindness,” and that’s part of the problem. The rest is blindness to the not-so-charismatic but important lives and needs of insects, spiders, and other animals that help make our world tick.

I leave you with one last photograph, of Signal Flies (Rivellia sp.) on a native plant, Toothed Spurge (Euphorbia dentata), along the same stretch of road yesterday. These flies look odd, but get used to it. Our feelings about their appearance should not dictate their survival, nor should ditch mowing dictate the survival of Toothed Spurge.