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Flying insects at risk as they escape to higher elevations

Their loss would have catastrophic effects on food supply and human survival
A monarch buttery makes a stop on a butterfly bush in a flower garden north of Durango in 2022. Many plants, animals and insects are moving to higher elevations to escape the effects of a warming climate. Jerry McBride/Durango Herald

Many plants, animals and insects are moving to higher elevations to escape the effects of a warming climate, but a strategy that is useful today may threaten their long-term future.

Researchers at the University of Colorado Denver and Georgia Institute of Technology say flying species including bees and moths are having a hard time moving to higher ground, which makes them even more vulnerable and puts them at higher risk for extinction, and that could create serious implications for humans in the future.

“When we think about where species will be able to live under climate change in the coming decades, we need to remember that animals are sensitive to more than just how hot or cold (environments) are,” said Michael Moore, assistant professor in the department of integrative biology at CU Denver, a lead researcher in a study published earlier this month that examined the dangers climate change poses to flying insects.

“If we want to design effective conservation strategies, we must consider a broader range of environmental factors that species need to live,” he said.

Scientists have been warning about the effects of climate change for decades but in recent years those rebukes have become louder and more consistent.

Over the past few years in Colorado, there have been wildfires, floods, mudslides and tornadoes. And while scientists have focused on mitigating those risks, others in the field say too little attention has focused on the tiny but important insects that are crucial for human survival and functioning.

Most crop pollinators are the flying species the researchers expect to be at risk and their extinction would be catastrophic for the food supply, according to the study findings.

Flying insects such as bees are unsung heroes in the agricultural systems people rely on for food because they pollinate some of the most important crops such as apples, mangoes and coffee.

And if the population declines or becomes extinct, humans will need to find other ways to sustain food production and the pollination it requires, “Or we’re all going to be in a lot of trouble,” Moore said.

Flying insects, such as butterflies, are also important food sources for many other animals and if they were to disappear, humans would see cascading effects on other bugs that no longer have access to one of their favorite food sources, he said.

Over the past few decades, an important prediction scientists have made is that plants and animals will respond to climate change by migrating to higher elevations where it’s slightly cooler, Moore said.

But high elevation environments have thinner air, less oxygen, stronger winds, fewer food sources and longer periods of extremely cold weather, which presents a barrier for the species moving there to escape the effects of global warming, Moore said.

The researchers used data from citizen science apps to track more than 800 insect species from around the world and compared rates of movement between the bugs that need the highest levels of oxygen to survive (bees and moths) with insects that require the lowest amounts of oxygen to live (ants and beetles).

Winged bugs, which need lots of oxygen to generate the energy needed for movement, are traveling to higher elevations at a much slower rate than their nonflying counterparts.

“For some species, maybe their maximum elevation is 100 meters above sea level and for others, it’s 12,000 feet, like here in Colorado,” Moore said. “And what we’re finding is it doesn’t really matter much about the actual elevation – species are having a hard time moving beyond their current maximum elevations.”

As the planet continues to change, it’s becoming increasingly important for scientists to understand where animals are going to live, so that they can help conserve those habitats, he said.

The new research has shown it’s not enough to consider only which habitats will be too hot or too cold for certain animals, he added. Other aspects of the environment need to also be considered, Moore said.

Insects are facing many other kinds of threats and easing the burden on them in any way will be beneficial while helping to fight insect declines, he said. For example, pesticides and herbicides are reducing the number of pests people don’t want to see, but the chemicals could also be detrimental to many of the insects humans rely on for agriculture, Moore said. “One thing we can be more judicious about is what we spray in our yards and how much.”

People can also help scientists understand where species are living now and where they might live in the future by contributing to citizen science apps like iNaturalist or eBird. The data iNaturalist collects, for example, includes the date and location where an observation was made and the information is fed into a database that also helps scientists understand where species are migrating to in response to climate change, Moore said.

“One of the main things we need to consider is we should try to make it easier for these animals to make it to higher elevations,” Moore said. “Right now, these species have to jump between unconnected patches of suitable habitat because the previous habitats have been broken up by things like agricultural lands or cities, and so creating corridors of suitable habitat that allows species to migrate into the higher elevations more gradually will be important.”

Migration has become harder and harder for all bugs, as skyscrapers and highways fill in open spaces, said Shiran Hershcovich, lepidopterist manager at Butterfly Pavilion in Westminster.

Monarch butterflies, fireflies, dragonflies, damselflies and the Bengal ornamental tarantula are threatened or vulnerable invertebrates currently being studied at Butterfly Pavilion where entomology teams are engaged in conservation breeding to help support declining insect populations. Many of those species were kept in cages while Hershcovich rattled off nerdy bug facts during a giggly interview.

Cave cockroaches, which crawled around in a cage there, are already extinct in the wild, she said. At any given time, Butterfly Pavilion has more than 350 invertebrate species, or animals that lack a backbone, on display that are also being studied.

The organization is working to install pollinator habitats in large developments, such as one in Broomfield, to protect native bees and butterflies, which play a crucial role in food production for humans and the reproduction of native plants. Leaders there are encouraging people to put certain plants such as milkweed and fennel in their backyards or balconies, so that butterflies and bees can stop to refuel, for example.

To help reduce insect decline, people can put plants in their backyards, reduce the amount of sound and light pollution they’re creating, volunteer at community science programs, avoid killing bugs and learn about insects to help reduce fear of them, Hershcovich said.

During the month of October, Butterfly Pavilion will celebrate spiders, educate the public about their importance in the ecosystem, and help people get up close and personal with the animal including by putting tarantulas on display. In November, Butterfly Pavilion will focus on celebrating monarch butterflies by having hundreds of them flying around in the conservatory and by sharing information about their cultural and ecological significance, she said.

Bugs are not necessarily as cute and cuddly as baby tigers and elephants, she said, but they matter and have a huge impact on humans’ daily lives. “I want to make sure invertebrates are protected, that they have a voice and that we can be their representatives,” Hershcovich said. “Because, often, they don’t get that.”

The Colorado Sun is a reader-supported, nonpartisan news organization dedicated to covering Colorado issues. To learn more, go to coloradosun.com.