Insects in Need

By Bonnie Chasteen | May 1, 2021
From Missouri Conservationist: May 2021
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stormwater pollinators
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Insects in Need
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Last May, National Geographic featured a story by Elizabeth Kolbert on global insect declines called Where Have All the Insects Gone? In it, she explored growing evidence that the world’s vital bugs are “disappearing at alarming rates.” Her story prompted one Conservationist reader to ask if Missouri’s insects are in decline, too.

To frame an answer, I consulted MDC Scientist Doreen Mengel. She had been working with research partners to study the effects of neonicotinoids, a widely used and highly potent class of insecticide, on Missouri conservation areas. Mengel and her partners conducted two studies, one on cropped areas in Missouri’s public wetlands and another on soybean fields planted with neonicotinoid-treated seeds and bordered by wildflowers assumed to be insecticide-free. These studies aimed to help MDC’s managers know if neonic-treated crops planted for wildlife like deer and turkey were affecting our Missouri ecosystems and native insect populations.

In both cases, the studies found that neonicotinoids were present. In wetlands, concentrations in water and sediment negatively affected aquatic insect abundance. In soybean field soils, neonics reduced the species richness of native bees.

Since Mengel had been thinking about insects and their threats and conservation in such detail, I hoped she could help me tell the reader how Missouri’s insects are faring.

She offered no easy answers.

“As with all things that involve dynamic populations and models,” she said, “there is likely no black-and-white answer and certainly no silver bullets.”

Insects are short-lived, she said, and their populations can rise and fall dramatically, depending on local conditions and weather. In addition, insects face many threats. Aside from pesticides like neonicotinoids, which can be widespread in agricultural areas, other pressures include “parasites, habitat loss, climate change, and invasive species,” she said.

Added to these threats, all of which can merge in highly affected areas, is the fact that we just don’t know as much about insects as we’d like to.

Our conversations were just the beginning of my education about why it’s so hard to know for sure how Missouri’s insects are doing.

It’s Complicated

MDC Heritage Entomologist Steve Buback keeps track of the state’s insects and their welfare. He specializes in pollinators like the monarch, and he also heads up MDC’s efforts to restore the federally endangered American burying beetle on Wah’Kon-Tah Prairie Conservation Area (CA), a 3,000-acre prairie remnant near El Dorado Springs. He explained why it’s hard to say, definitively, if insects are declining in Missouri.

“There’s lots of anecdotal evidence (in the Midwest), but we don’t have the long-term studies (like those in Europe and the Western U.S.) needed to provide those numbers,” he said. “If we started (those studies) now, we still wouldn’t know for several decades.”

Buback estimates Missouri has around 25,000 insect species, “but no one truly knows,” he said. “There are over 450 bee species alone, which is more than there are species of birds, and there are more grasshopper species than there are of reptiles. We are currently working to get the number (of insect species in the state), but it will probably take a lifetime and a lot more people working on it,” he said.

Buback also echoed Mengel’s point that it can be hard to know exactly what’s driving a species’ decline.

Missouri’s efforts to restore the American burying beetle illustrate the challenge of returning a native insect to what seems to be suitable habitat.

This carrion-eating beetle once lived in 35 states, but, as America’s vast prairie landscapes declined, so did the beetle’s numbers. It hasn’t been seen in Missouri since the 1970s. About 10 years ago, MDC partnered with St. Louis Zoo to raise and release some adult beetles at Wah’Kon-Tah Prairie CA. Although the restoration team’s annual monitoring efforts have detected signs of reproduction — adult beetles and grubs — the population is far from stable. During 2020 monitoring, the COVID-19 pandemic kept the zoo’s monitoring staff at home, leaving the task to Buback’s team. They found only one beetle.

“We don’t actually know the cause of their decline,” Buback said. “Some theories are related to carrion availability, competition from other burying beetle species, light pollution, or potential disease issues.

“We have been working on this species for over a decade now, and we are just getting to the point where we have population estimates. But we don’t yet have the knowledge to identify causes or to fix them.”

He explained that lack of knowledge is part of the process. “Any species we start to learn more about, it just leads to more questions.”

Long-Term Studies Detect Signals of Change

If we need more research, especially long-term studies, what about MDC’s Missouri Ozark Forest Ecosystem Project (MOFEP)? Launched in 1991, this comprehensive effort aims to measure the forest’s response to management for 100 to 200 years. Had anyone studied insects in the first 30 years?

Buback introduced me to Robert Marquis, recently retired from the University of Missouri–St. Louis Biology faculty. During his career, he worked with MOFEP partners to conduct a 20-year study of leaf-chewing insects (think moth and butterfly caterpillars, beetles, grasshoppers, walking sticks, and katydids) on Missouri oaks. The goal was to understand the impacts of forest management on them. In the process, the study tracked their declines and resilience following mid-spring frosts and summer droughts. These data could potentially help the team detect evidence of climate change.

“We knew if we did see a signal of climate change on declining populations, this (MOFEP study area) would be the place because it’s so isolated and thus relatively undisturbed,” Marquis said.

Marquis’ team showed that impacts of short-term events could last up to five years, but, in 20 years, the study found no evidence for a general decline in abundance. However, he said, “those short-term events make it difficult to see the long-term events of climate change.”

“It could be that the actual frequency (of detrimental mid-spring frosts) is increasing over time. (Some) evidence suggests that it is. That would be a signal of climate change. We could have more droughts, too,” he said.

Marquis noted that the manager’s job is to provide habitat for native communities to live in. “That person could be really good, but if climate change is disrupting the weather, no matter what you do, you’re going to be stuck. The manager can affect local living conditions for plants and animals, but climate change of course is the result of policies and activities happening at a global level, and they only can be ameliorated with a global effort.”

That sounds grim, I said. “How can we hope to manage?”

“I’ll say two things,” Marquis said. “We finished up last spring sampling butterfly communities near MOFEP and over near Branson on sites that had not been burned and other locations that had been. We found a huge beneficial impact in areas that had been managed with fire for nectar plants (like coneflower and blazing star).

“If you know what you’re doing, and you actively manage the habitat, you can have a positive impact,” he said.

Monitoring is Essential

Until we have more data from more long-term studies, monitoring helps us track insects of special concern or significance, as Buback’s work with the American burying beetle shows.

Community and Private Land Conservation Branch Chief Bill White is excited about a new way MDC is working to keep tabs on Missouri’s bumblebees.

“They’re easy to identify without a microscope,” he said. “And photo-monitoring helps us track presence and population size over time,” he said. “It really helps us answer in a more specific way, Are insects declining in Missouri?

The new web-based program is a partnership with Quail Forever, the University of Missouri, and the Xerces Society for Invertebrate Conservation, and it invites citizens statewide to participate.

“First you need to select somewhere to monitor, whether that is in your backyard, farm, or a local park or natural area,” White said. “The Missouri Bumblebee ATLAS Project has online tools to help you ID Missouri bumblebees. Then all you need to do is take photos and upload them to the database at least a couple of times a year.”

Buback added that bumblebees can be a good indicator of available pollinator habitat. “They’re long-lived, and they need a diversity of blooming flowers throughout most of the year,” he said.

To learn more and get involved, visit MoBumblebeeAtlas.org.

A Homegrown Conservation Area

Research and monitoring can help us know more about Missouri’s insects. Restoring and conserving their essential habitat can help us keep them secure in our state.

Since publishing Bringing Nature Home: How You Can Sustain Wildlife with Native Plants in 2007, renowned entomologist and author Doug Tallamy has taught Americans to see insects, which need native-plant habitat, as bird food. Last May, a National Wildlife Federation survey reported that one in four Americans purchased a plant specifically to benefit birds, bees, or butterflies. In Nature’s Best Hope, published in 2020, Tallamy wrote that if each of us turned half our lawns into native plants, we could create a homegrown national park “the equivalent of nearly ten Yellowstones.”

Here in Missouri, we can start by creating a homegrown conservation area. With so many partners like the Missouri Prairie Foundation and Missourians for Monarchs, the Show-Me State is rich in local sources of information, help, and good examples of habitat restoration. With this wide network of experts and our common store of know-how, we can make the whole state of Missouri safer for insects and all the creatures that depend on them — including us humans.

Nature’s Essential Workforce

If Earth’s invertebrates vanished, the rest of the planet’s lifeforms would soon follow. Countless land and water insects make up our essential workforce, sustaining life for all.

  • Invertebrates provide food for wildlife. According to entomologist Doug Tallamy, it takes 9,000 caterpillars to fledge a nest of chickadees.
  • They manage waste. Without insects like the federally endangered American burying beetle, dead plants and animals and dung would never rot, and nutrient cycling would slow or cease.
  • They control pests. Predatory insects like wheel bugs eat plant-killing insects like Japanese beetles, saving farmers billions annually.
  • They pollinate our food. No pollinators like monarchs and bumblebees means no tasty apples, blueberries, or tomatoes. Many of these crops are better pollinated by native wild bees than by domesticated European honeybees.
  • They make soil hold water. Without ants and other soil bugs, soil would harden, plants would die, and every rainstorm would become a gully-washing flashflood.

Our mission benefits insects

MDC is a science-based agency with strategic and wildlife action plans that are habitat focused. “Our efforts to restore and conserve habitat statewide naturally benefit insect communities,” said MDC Natural Community Ecologist Mike Leahy.

“As our research has shown, there’s pretty good correlation between intact and functioning plant communities that are buffered from insecticide application and high levels of insect diversity and abundance.

”Landscape context is important, too,” he added. This is because insects and plants are co-evolved, meaning that some species of plants can’t survive without some species of insects, and vice versa.

Because Missouri is 93 percent privately owned, MDC depends on partners to achieve our mission at the local level. In recent years, we’ve worked with hundreds of agencies, local governments, nonprofits, businesses, and private landowners to create, restore, and conserve almost half a million acres of pollinator habitat.

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Monarchs are magnificent, but Missouri has tens of thousands of other watchable insects to notice, name, and care about. A good starter field guide is MDC’s Show-Me Bugs. It introduces you to 50 insects and other invertebrates you’re likely to see in your yard, garden, or farm. It’s available at most MDC nature centers. Another good resource to help identify insects is the MDC online Field Guide, available at mdc.mo.gov/field-guide.

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Even if you live in an apartment in town, you can provide habitat for native insects. In fact, a recent study found that St. Louis hosts 45 percent of Missouri’s native bee diversity. Plant a few blooming native wildflowers like butterfly milkweed and purple beardtongue in a pretty container on your balcony or porch. They will soon attract nectar-sipping pollinators. If you’re new to native plant gardening, check out grownative.org for plant lists and designs that work in sun or shade. If you farm, contact your county’s private land conservationist (PLC) at mdc.mo.gov/contact-engage. Your PLC can help you add native plant borders to your crop fields and drought-resilient native grasses and wildflowers to your forage system.

Also, leave the leaves where they fall in the fall. Leaves shelter over-wintering cocoons like that of the giant Polyphemus moth.

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MDC Forest Entomologist Robbie Doerhoff cautions homeowners against using lawn insecticides. “When you put out grub granules, they kill nearly every insect they come into contact with. And sometimes the insecticide is taken up by flowering plants, making them toxic to bees and butterflies,” she said.

Along with crop monitoring, borders of native wildflowers selected to provide blooms all season long can be part of an effective insect-control program. In addition to pollinators, they harbor pest-eating native predator insects like ambush bugs and parasitic tachinid flies.

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As we’ve seen, just keeping track of the presence and abundance of insects can help us know if their populations are secure or declining — and what may be helping or hurting them. Check out the Missouri Bumblebee ATLAS Project at MoBumblebeeAtlas.org and learn to monitor native bumblebee species where you live.

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Encourage your local government to adopt community conservation practices that provide habitat for pollinators and other wildlife in town. Visit mdc.mo.gov/community.

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The Missouri Master Naturalist program has chapters all over the state, and many of them are involved in insect studies. To find a chapter near you, visit short.mdc.mo.gov/Z8u.

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This Issue's Staff

Magazine Manager - Stephanie Thurber

Editor - Angie Daly Morfeld

Associate Editor - Larry Archer

Photography Editor - Cliff White

Staff Writer - Bonnie Chasteen
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek

Designer - Shawn Carey
Designer - Marci Porter

Photographer - Noppadol Paothong
Photographer - David Stonner

Circulation - Laura Scheuler