How Scientists Are Working to Reverse Colorado’s Bug Decline

A recent trip to Florida solidified my love for Colorado. After waking up to a horrifyingly large millipede on the wall of a Palm Beach Airbnb, running through clouds of blood-sucking mosquitoes, and dodging cockroaches skittering down sidewalks, I fell head over heels all over again for a place I’d long appreciated for its dearth of vermin. That is, until I learned a buggy environment is an ecologically sound environment.

Insects are the most varied and plentiful animals on Earth. Their existence allows for not only healthy ecosystems, but also for the very existence of many other species, including humankind. According to Rich Reading, vice president of science and conservation at Westminster’s Butterfly Pavilion, insects serve as meals for the rest of the food chain, pollinate plants that humans eat for dinner, and control invasive pests that attack native plants and animals. In short, bugs are far more critical than their relatively diminutive size might suggest, which is why Coloradans—and human beings in every corner of the planet—ought to be concerned about their rapidly declining numbers. “Colorado is drier than a lot of states, so we naturally tend to have fewer bugs than places like Florida, but there used to be more,” Reading says. “We’re dealing with what some are calling a ‘bug apocalypse.’  ”

That term stems from a 2017 study done in Germany showing that flying insects in the country’s nature reserves decreased by more than 75 percent over 27 years. But it was a 2019 review in Biological Conservation that confirmed the problem is more widespread. According to the study, 40 percent of all insects worldwide are threatened with extinction. While scientists have yet to figure out a definitive cause, there are a few main suspects—namely climate change, pesticides, the global spread of invasive insect species, and human development.

Colorado isn’t sidestepping the bugtastrophe. In fact, research by the Rocky Mountain Biological Laboratory published in 2023 showed a 62 percent decline in flying insects near Crested Butte since 1986. And earlier this year, a report commissioned by the Colorado Department of Natural Resources concluded that the status of Colorado’s native pollinating insects is “tenuous.” Plus, three butterflies native to Colorado are currently listed under the Endangered Species Act. “I don’t know if anyone really knows what’s going on,” says Marek Borowiec, an assistant professor of agricultural biology at Colorado State University. “But it’s vitally important we understand.”

That’s why the Butterfly Pavilion and CSU announced a partnership in February that will lead to shared resources and funding to research invertebrate decline. Researchers from institutions such as the University of Colorado Boulder and University of Colorado Denver are stepping in, too, all of which caught the eye of local lawmakers. On May 17, Governor Jared Polis visited the Butterfly Pavilion to sign House Bill 24-1117 into law, which gives Colorado Parks and Wildlife (CPW) the authority to study invertebrates and rare plants and develop plans to protect species in danger. Previously, Colorado was one of just nine states that did not already give its wildlife officials such authority. According to Reading, the designation will vastly improve research in the state. “It’s really going to take all of us working together, because this is a lot of work,” he says. “We can be a lot more effective and synergistic in our impacts by partnering with one another.”

While it’s not exactly the end of the world as we know it (yet), we spoke with scientists, state researchers, and local organizations who are fervently working to prevent a bugtastrophe here at home.

Jump Ahead:

• Conservation
• Invasive Species
• Where To See Bugs
• Colorado’s Bug Trouble By the Numbers

---

Conservation

Although you might be tempted to swat at those pesky critters that seem to always swarm your summer picnic setup, some native insects are on a scary downward spiral. Luckily, experts are finding ways to save Colorado’s useful pollinators, rare butterflies, and magical glowing fireflies.

Pollinators

In January, Governor Jared Polis revealed results from the 306-page Colorado Native Pollinating Insects Health Study, a research project prompted by Senate Bill 22-199. Based on more than a century of already completed studies, the report confirmed a drastic decline in pollinators in the state. Adrian Carper, entomology curator adjoint at the CU Museum of Natural History and one of the study’s co-authors, spent months analyzing existing scientific literature to help pen the report. While the authors found that more than 1,000 species of bees exist in Colorado, one of the largest factors contributing to their demise has been the conversion of natural habitat to agricultural land, which destroys endemic flora.

Carper suggests that instead of renting bee colonies from commercial beekeepers, savvy farmers can use strategically placed native plants to attract pollinators to naturally fertilize their crops while simultaneously offsetting the damage that agriculture can wreak. “Crops depend on native pollinating insects to make the most fruit,” Carper says, “and by managing the surrounding habitat, farmers can pollinate those crops for free without paying honeybees to do it.”

3 Local Sanctuaries for Pollinators

Thanks mostly to human development, Colorado’s pollinators are dying. That’s not just unfortunate news for the insects; it’s a beeline toward disaster for native flora that depend on the insects for genetic diversity. With that in mind, in 2019 the Butterfly Pavilion launched Pollinator Districts, a designation that turns human-made sites—like roads, neighborhoods, and even entire cities around the globe—into insect refuges. Through the program, Butterfly Pavilion scientists either inspect existing communities or study the land of future developments before providing town officials or developers with recommendations on how to create buzzworthy locales that counteract the destruction of native plants often brought by development. “When you create a diverse landscape with native plants that are drought-resistant, you create an environment that attracts all sorts of wildlife,” says Patrick Tennyson, president and CEO of the Butterfly Pavilion—which in 2022 turned a beachfront neighborhood in Turks and Caicos into a pollinator haven.

Here in Colorado, the bees are busy at these three Pollinator Districts.

I-76

This 184-mile-long highway, which runs from Denver to the Nebraska state line, became a Pollinator District in 2018 after the state proclaimed it the Colorado Pollinator Highway in an effort to protect insect habitat. Since then, road crews have avoided mowing grassy areas during peak pollination season (April through September), and the state has employed a roadside manager to promote the growth of native plants and weeds along the highway.

Manitou Springs

Last summer, Manitou Springs became the world’s first municipality to receive a Pollinator District designation by installing green roofs and creating public gardens. This year, residents were invited to take part in Pollinator Palooza, a three-month-long event. Participants uploaded photos of pollinators they encountered to an app that tracks the various species. Those who submitted the most photos earned prizes, while the information gathered will help the city maintain its designation.

Baseline

While this Broomfield neighborhood dotted with new builds might look like any other suburban development, its carefully designed parks and gardens are filled with native plants that attract insects. Research conducted by Butterfly Pavilion scientists has shown a 60 percent increase in pollinators in the area since Baseline became a Pollinator District in 2019. And the work doesn’t stop there: In an effort to further prop up pollinator populations, the Butterfly Pavilion plans to open an 80,000-square-foot campus—complete with green roofs and native gardens—adjacent to the neighborhood by 2028.

Fireflies

Fireflies are native to Colorado, but you wouldn’t know it. These little glowing beetles typically thrive in wetlands, like in marshes at the edges of lakes and streams. They were once plentiful across the state, but today they’re only found in a few small pockets, including at Littleton’s Chatfield State Park and Fort Collins’ Riverbend Ponds Natural Area.

Magical as they are to witness, the twinklers are more than meets the eye: Lightning bugs are a so-called indicator species, which means their population numbers are directly correlated to the health of the surrounding ecosystems. The fact that they’re hard to spot in Colorado today is alarming: It serves as proof that their native wetlands are being destroyed by development and water pollution. That’s why, in 2019, the Butterfly Pavilion started an initiative called the Firefly Life Cycle Project, an effort to understand the insect’s life cycle and potentially learn how to rear it in captivity.

In 2021, the project’s scientists captured wild fireflies, bred them, and attempted to raise the larvae. Their first major success came in June 2023, when three lab-born fireflies matured into adults. That’s a tiny number, sure, but according to Jennifer Quermann, senior director of communications and marketing at the Butterfly Pavilion, this is the first known successful rearing of captive fireflies to adulthood on Earth. Butterfly Pavilion researchers hope that, eventually, they’ll have enough fireflies to populate a sanctuary and create an exhibit for the beetles—and maybe even introduce them back into the wild someday. “Ultimately, the goal is to create a sustainable population of lab-reared fireflies,” Quermann says, meaning Colorado’s night skies might one day be lit up with luminescent flickers once more.

Silverspot Butterflies

If you visit the moist, open meadows of southwestern Colorado, you’ll increase your chances of seeing a Speyeria nokomis nokomis, a subspecies of a larger family of butterflies known as the Silverspot, recognizable by its large, three-inch wingspan and black-with-cream-colored-spots pattern on its underside. As lovely as it is, this winged dazzler is also a relatively rare sight: Only 10 populations exist throughout Colorado and surrounding states. This past February, the U.S. Fish and Wildlife Service (FWS) announced that the insect would receive protections under the Endangered Species Act and categorized it as threatened. “The butterfly requires wet meadow areas to survive, and climate projections are predicting a warmer and drier future,” says Terry Ireland, fish and wildlife biologist with FWS’ Colorado field office. “Climate change was a big driver for our threatened determination.” That designation means that while the butterfly is likely to become endangered, it will get protections, such as federal funds, that aim to prevent that possibility.

---

Invasive Species

Bugs native to other parts of the planet have been known to move out of their home environments—which leads to the destruction of the new habitats they choose to settle into. Local scientists are working to minimize their impacts here in Colorado and beyond.

Colorado Potato Beetles

As much as Coloradans enjoy bad-mouthing Californians and Texans who make their ways to the Centennial State, one native Coloradan who left home has made life a whole lot more difficult for the rest of the planet. The Colorado potato beetle, a tiny, round insect with an orange body and black stripes, is indigenous to the Centennial State but began traveling the world by hitching rides on transported produce in the 1860s. Now, it can be found grubbing on potato plants throughout the United States, Europe, and Asia, where it has the potential to defoliate entire fields of crops in just a year or two.

According to Marissa Schuh, an extension educator with the University of Minnesota who helps farmers there manage the pests on their crops, the beetles are nearly impossible to eradicate from farmland once they’re found, but there are ways to control their populations. Farmers can employ crop rotation (planting different crops each season on the same piece of land) to keep beetle numbers low. Home gardeners should consider buying ladybugs: They eat beetle eggs for breakfast.

Peach Moths

The breezes here are different. They blow down through De Beque Canyon and unfurl across the Grand Valley town of Palisade. Known as katabatic winds, the warm air they deliver reduces chances of frost. Those breezes create a unique weather pattern that, among other things, makes for some of the world’s finest peach-growing conditions. The temperate microclimate attracts fuzzy-fruit lovers from around the globe, but tourists aren’t the only ones who love the sweet taste of a Palisade peach.

In the early 1900s, a 10-millimeter-long, gray-colored moth hitched a ride on a vessel from Southeast Asia that was carrying cherry trees. The Grapholita molesta, or peach moth, spread throughout the country by 1945. Today, the moth is found wherever stone fruits are grown, including in Colorado’s peach capital.

Each spring, females lay their eggs on the surfaces of peaches, a brilliant example of survival of the fittest evolution that not only provides freshly hatched larvae with an easy snack when they dig inside the fruit, but also makes topical pesticides useless. So, in 1946, the Palisade Insectary, a state-run lab that raises insects that attack invasive bugs and plants, started building an army of millions of moth-killing wasps each year. The Macrocentrus ancylivorus (dubbed the Mac, for short) uses a sharp appendage called an ovipositor to saw into the peaches, where it lays its eggs inside the moth larvae it finds. When the baby wasps hatch, they eat the larvae from the inside out. It’s brutal, but Kristi Gladem, biological control specialist with the Palisade Insectary, says it’s proven to be effective. “The wasps keep the numbers low,” she says.

Peach growers can apply to the insectary to receive free wasp pupae (roughly 1,000 per acre of orchard), which they hang in trees to hatch. It only takes a few days for the adult wasps to break free and immediately search the orchards for moth larvae.

And while the Palisade Insectary remains focused on controlling Palisade’s moth population, the lab is also available to assist other agencies with invasive species. For instance, a decade ago, Boulder Parks and Recreation detected emerald ash borers on public land; the beetle is native to Asia and feasts on ash trees. Lab workers released four species of wasps, all of which are related to the Mac but are bred to attack the beetles instead of moths. The city of Boulder is currently participating in research to determine the effectiveness of those wasps, but Gladem notes that early results have been promising. Although Boulder still hosts a population of emerald ash borers today, the numbers are manageable.

The Palisade Insectary stands ready to provide other Colorado cities with biological controls if there are future outbreaks. However, Gladem and her team are also working on something else: rearing insects for control of invasive plant species. The northern tamarisk beetle, for example, eats the invasive tamarisk shrub and should be able to get the population of weeds on the Western Slope under control within the next few years. Still, the Palisade Insectary’s golden child is the Mac wasp, which it continues to breed annually by the millions—a job that allows all of us to, without hesitation, bite into the sweetest peaches around.

3 Invasive Bugs on the Loose in the United States

Invasive species have the potential to damage native ecosystems and cause disastrous economic impacts, which is why the Cooperative Agricultural Pest Survey (CAPS), a nationwide program from the U.S. Department of Agriculture (USDA), is tasked with detecting and managing pests that have set up residences where they shouldn’t. If you see an invasive bug, CAPS’ Colorado program manager, Kristin Wolfe, recommends taking a photo and reporting it to the Colorado Department of Agriculture. Even better, if you aren’t squeamish, capture the insect and place it in a freezer to humanely euthanize it before sending it in for physical inspection. We asked Wolfe to blow the whistle on three bugs currently running from the law.

1. Asian Longhorned Beetle

Native to Korea and China, this spotted beetle is easily recognizable by its antennae, which are often longer than its body.

Charged with: Boring into hardwood trees, where it lays its eggs. The resulting larvae feed on the timber, causing the tree’s untimely death.

Possible sightings: So far, the beetle has only been seen in Massachusetts, New York, New Jersey, Illinois, Ohio, and South Carolina. What makes it the stuff of Wolfe’s nightmares, though, is that the USDA has not yet approved a method of trapping the insect, meaning it’ll be incredibly difficult to detect if (or, more likely, when) it decides to relocate to Colorado, where it could destroy acres of bark in the state’s forests.

2. Spotted Lanternfly

This planthopper (a group of small bugs that catapult themselves from leaf to leaf) is native to China and first arrived in the United States through an international shipment of stone in 2012.

Charged with: Chomping on grapes and apples and sucking fluid from under the bark of hardwood trees. Adult lanternflies and immature nymphs also love to grub on the tree of heaven, an invasive plant that has only minor distribution in Colorado.

Possible sightings: The spotted lanternfly hasn’t made its way to the Centennial State, with the exception of one dead specimen found in a shipment a few years back. Still, the pest is destructive enough that Wolfe considers it an “insect of most concern” and expects it will come to Colorado within a decade.

3. Spongy Moth

Formerly known as the gypsy moth, this fuzzy insect is native to Europe and Asia but has been caught terrorizing the United States since 1869.

Charged with: Producing really hungry offspring. Its caterpillars aren’t picky eaters and will chow down on more than 300 species of trees and plants, with a preference for aspen, birch, and willow trees.

Possible sightings: Mainly found on the East Coast, the moth has gnawed on trees across 20 states so far. While it doesn’t yet have a presence in Colorado, the USDA has placed thousands of traps across the state to try to immediately spot it when it arrives.

---

Where to See Bugs

While Colorado experts are furiously formulating ways to save local insects, they also use their expertise to oversee exhibits and museums throughout the state that are open to the public. Here, four ways insect-curious Coloradans can get involved.

1. May Museum

Inside the family-run May Museum in Colorado Springs, Diana Fruh curates one of the world’s largest collections of tropical insects in a space her great-grandfather, James May, founded.

What to see: Before you catch a glimpse of the 7,000-plus insects on display at the museum, you’ll be greeted by Herkimer, a giant replica of the Hercules beetle, who overlooks CO 115. You’ll find the real thing, a beetle that can grow up to seven inches long, in the museum’s exhibits.

Why you should care: James May spent 80 years, nearly his whole life, traveling the world and collecting insects—whether by hand or through trading with collectors—along the way, making this private collection an in-depth look at some of the world’s rarest bugs.

2. C.P. Gillette Museum of Arthropod Diversity

At the C.P. Gillette Museum of Arthropod Diversity at CSU, director Marek Borowiec and his team care for nearly five million insect specimens housed on campus.

What to see: Examples of more than 90 percent of all North American butterfly species are kept in the museum, where they take up nearly 3,000 drawers. The butterflies are used by scientists working on reports, studies, or field guides and represent nearly all of Colorado’s butterfly species.

Why you should care: Graduate students at CSU and scientists from other institutions are eligible to apply to borrow museum specimens for their research, something Borowiec and his staff are eager to accommodate to spread insect knowledge and help preserve their natural environments.

3. Butterfly Pavilion

Westminster’s Butterfly Pavilion is the world’s first invertebrate zoo accredited by the Association of Zoos and Aquariums and provides visitors with five immersive exhibits focused on insects in Colorado and beyond.

What to see: Step into the Wings of the Tropics exhibit, where butterflies freely flutter around a 7,200-square-foot tropical sanctuary space (wear bright colors if you want them to land on you), or visit the Survival exhibit, where the brave can hold Rosie the tarantula.

Why you should care: Butterfly Pavilion researchers work to conserve insects both in Colorado (by rearing captive fireflies and dragonflies for reintroduction, for example) and abroad (like by constructing a butterfly farm in Sumatra).

4. CU Museum of Natural History

Located on CU Boulder’s campus, the CU Museum of Natural History houses more than 1.4 million insects and 60,000 arachnids in its entomology collection, including many species only found in Colorado.

What to see: While the full collection—which has an especially large array of bees, butterflies, and leafhoppers—is not on display, visitors can schedule a visit by appointment to learn and see more.

Why you should care: The specimens in the collection are often loaned out to scientists and students who use them for research. For example, a project studying 24,000 grasshoppers collected along Colorado’s Front Range since the 1950s is allowing scientists to learn how climate change has affected the insects since then.

5. Southeast Colorado

Every September, people flock to rural Baca County in southeast Colorado to catch a glimpse of spiders scurrying across CO 109. While the long-leggers might seem like they’re moving to a new home base, the phenomenon isn’t technically a migration for the male Oklahoma brown tarantulas. Instead, the Butterfly Pavilion has dubbed the spectacle a mate-gration. When a male finds a female’s burrow, he’ll knock on her door (by drumming his appendages) and try to quickly mate before the female has a chance to eat him. The species isn’t endangered, but the location of its breeding grounds means the spider is often turned into roadkill by highway traffic. According to the Butterfly Pavilion’s Rich Reading, these eight-legged wonders are a critical part of the food chain, which is why local scientists are exploring ways to protect them, potentially by building tunnels that go under the highway to let the tarantulas cross safely.

---

Colorado’s Bug Trouble By the Numbers

• 800: Species researched in a CU Denver–led study, which found that flying insects are migrating to higher elevations due to climate change, contributing to their declines as they struggle to adapt to new environments
• 20: Percent of bumblebee species in Colorado that are considered threatened, according to a state-commissioned pollinators report released in January, leading experts to call for federal protections for the bees
• ~233,000: Monarch butterflies counted in 2023 by the Western Monarch Count, a volunteer-led initiative affiliated with the international nonprofit Xerces Society for Invertebrate Conservation, showing that the butterflies have seen a 95 percent decline in the western United States since the 1980s
• 202,000: Acres in Colorado affected by the Western spruce budworm, the most widely spread forest pest in the state, which kills spruce and Douglas fir trees through defoliation, according to the 2023 Forest Health Report from the Colorado State Forest Service