Climate change could drive new insects into Summit

Janice Kurbjun
Summit Daily News
ThinkStockA warmer climate in the mountains can mean more pesky insects, but some more desirable ones as well - such as the queen butterfly.

If climate change continues, it could bring nuisance insects into the High Country that typical cold snaps keep away.

Like ticks.

And mosquitoes that overwinter more easily.

The mountain pine beetle has already made its presence known, as it reproduced in the warmer environment and caused trees to die when they didn’t have enough moisture and nutrition to bounce back from the onslaught.

At the same time, consistently warming temperatures in Colorado’s mountains could bring more beautiful species, like butterflies, into abundance.

Bob Hammon, an entomologist with Colorado State University extension office in Mesa County, has noticed more migratory butterflies, such as the queen, which is in the monarch butterfly family, and the painted lady and variegated frittilary.

“I’ve seen (the queen) in the 30-plus years I’ve lived in Colorado, but I’ve seen it more this year and I’ve seen in the past.”

He said he’s also seen his first giant yucca skipper of the season, which is typically found further in the southwest.

As for ticks, Hammon said there have always been a few at higher elevations, but they’re not that common.

“I’ve seen some ticks at 10,000 feet and higher in the past, in the 1980s and all,” he said, adding that insects move with the temperature. If it warms, they’ll seek cooler sites either higher in the mountains or at more northerly latitudes.

Though ticks might become more of a nuisance for Summit County recreationalists, the caddis flies are becoming more of a show.

This year, Hammon speculates the lack of ice in Glenwood Canyon allowed more caddis eggs to survive the winter.

“There was a huge emergence of them last week,” he said. “I heard some reports of them clogging up radiators of vehicles.”

Mosquitoes are less temperature-dependent and more moisture-dependent – and this year, the hatches might not happen. Meaning fewer mosquitoes to swat as hikers trudge through dusty wildflower fields.

“Some of the highest mosquitoes population densities occur in the Arctic, which during much of the year is colder than Colorado at 9,000 feet. The Arctic has more moisture and far more standing water than the Eastern slope of the Rockies,” Purdue University professor Jonathan Neal said.

Three types of mosquitoes are most common in Colorado, and all depend in some way on water for their eggs to hatch.

The snowmelt mosquitoes won’t hatch because there was little runoff, but those eggs will stick around for the next year snowmelt pools occur, Hammon said.

Floodwater mosquitoes typically lay their eggs on soil and wait for the soil to become wet. With soil drier than it’s been in a decade, these mosquitoes aren’t going to hatch, either.

Other mosquitoes lay their eggs in stagnant water, which again will be less this year.

“If we have less habitat for them because of the drought, there will be fewer going into the winter and fewer next,” Hammon said.

He does expect warmer temperatures to influence the spruce beetle and mountain pine beetle populations in the currently unaffected Gunnison County forests. Trees stressed through drought, increasing populations of the insects through mild winters, and a mature acreage of spruce and pine means “we’re set up,” Hammon said. “It hasn’t happened yet, but I’m pretty nervous.”

Most research supports the theory that many insects will move according to changing temperatures, but Neal said it’s more complex than that.

“Climate is complex, which makes changes from greenhouse gasses difficult to predict for specific locations. Climate change will produce more extreme weather events in all areas,” he said. “Ecosystems are even more complex and interact with climate. Few ecosystems are understood in a level of detail that predictions based on climate can be made. Where temperature is a barrier, warming can extend the ranges of some species northward or to higher elevations.”

Temperature isn’t always the barrier, though.

“The barrier may be precipitation or humidity or other abiotic factor or the barrier can be biological. Diseases, parasitoids, predators, key hosts, can all affect distribution of a species. It would be a mistake to generalize about future mosquitoes populations in Summit County or any other county given the current state of knowledge,” Neal said.

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