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Insect death trap? UW study assesses risks posed to bugs by wind turbines

INSET: Two sweat bees seen under a microscope (Amy-Marie Storey). Michelle Weschler Setting up a vane trap south of Medicine Bow, Wyoming (Lusha Tronstad).

LARAMIE, Wyo. — While many contemporary criticisms of wind energy are focused on the risks turbines pose to larger winged creatures like birds and bats, one University of Wyoming entomologist focused her research on what the mechanisms do to insect abundance. In a new study, researchers looked at nearly every feature of the devices to determine their effects on the small scale.

Michelle Weschler, assistant research scientist at UW’s Wyoming Natural Diversity Database and lead author of “Wind energy and insects: reviewing the state of knowledge and identifying potential interactions,” said that it’s already been established that concerning data exists relating to bug populations worldwide. The focus of this paper, then, was to compile existing information and localize those concerns to Wyoming.

Weschler, left, and UW masters student Amy-Marie Story. (Lusha Tronstad)

“For a lot of these conservation concerns, bugs are an afterthought,” Weschler said. “I think it’s pretty clear that there is a decline happening all over the world, but it kind of depends on where you look.”

So, are turbines harming insect populations here in Wyoming? First, it is useful to assess what turbines actually do to insects.

A turbulent relationship

An important feature of Weschler’s study, which was co-authored by fellow Wyoming Natural Diversity Database researcher Lusha Tronstad, is its compilation of previous research to size up what bugs are attracted to regarding turbines and to what extent they are attracted. Given that in some areas of the world researchers have found that the total biomass of insects has declined by more than 75%, there is clear incentive to get to the bottom of this.

One alarming finding is that insects are drawn to the striking color of turbines, which are typically a bright white. The white’s heavy contrast against the natural landscape and its emission of ultraviolet color waves, according to researchers, draw insects in where they are liable to be killed by spinning turbine blades.

“Maybe insects are thinking that turbines are these big homing beacons that they can go to. There’s evidence they swarm around turbines,” Weschler said. “We’ve found through LIDAR studies that insects are swarming around their tops.”

What is LIDAR?

LIDAR, which stands for Laser Imaging, Detection and Ranging, is a process of scanning a distant area with a laser to determine ranges, or how far away something is.

While the technology has applications across all sciences and in nearly every possible environment, it is used in the above scenario by scanning the air around turbines and measuring when light reflects back. Depending on where in the air the laser reflects back to the measuring device, researchers can determine if there is something, such as an insect, suspended in the air that they could not otherwise see or access.

So, using LIDAR, researchers are able to assess the density of insects in hard-to-reach places, like around the spinning blades of a wind turbine.

Another potential attractant is the turbines’ radiant heat. They are, after all, giant generators. Weschler added that, especially here in Wyoming, it might be helpful to think about the ways turbines could act as a form of shelter for insects from environmental factors.

“They might, you know, get on the other side of them to avoid high winds,” Weschler said. “They might even stick around because [researchers] have found evidence of them overwintering and resting there, even though it makes them potentially more attractive, or visible, to predators like birds and bats.”

That compounds the concern, then, because birds and bats are themselves extremely vulnerable to meeting their end at the hand of turbine blades. If winged vertebrates are attracted to insects resting on turbines, their lives are in danger, too.

This is a mutually detrimental relationship for the turbines and their vested creators as well. One paper that Weschler and her co-author cited in their research found that accumulated insect bio-debris on turbine blades can so much as halve power generation.

All of that is to say that there is some sort of negative relationship between the man-made monoliths and the winged insects of the world. Weschler, then, sought to find out to what extent that was an issue locally in Wyoming for one of the state’s most abundant and beneficial creatures: bees.

“Is it making an actual difference in their population? Their abundance? Their ecological niches? We don’t know that yet,” Weschler said.

The Wyoming insect case study

Looking at insect populations in different areas around operational wind farms and sites slated for future development, the researchers monitored insect abundance and richness. They set out 83 vane traps across six field sites over 13 sessions, according to the paper.

“The abundance of insects, primarily bees, did not differ with distance from turbines,” the paper stated. “We captured 1,614 insects, 95% of which were bees. The abundance and richness of bee taxa captured in vane traps did not vary with distance to turbine across the landscape at the scales we investigated.”

Weschler Examining flowering plants within a wind energy facility in southeast Wyoming (Lusha Tronstad)

Does that mean that insects, or at least bees, are not threatened by turbines? Not necessarily. The overwhelmingly supported scientific understanding is that all insects are threatened by turbines — compiling that information is half of what Weschler’s study sought to do. Additionally, this is one taxa of insect in one portion of Wyoming studied over one short period of time.

There are plenty of insects still present at wind facilities, as the case study points out. Weschler clarified that her findings do suggest that abiotic factors like wind speed and temperature do affect insect abundance, and those are factors that are impacted by turbine presence.

While this specific case study doesn’t necessarily make any bombshell revelations, Weschler still argues that there is something Wyoming residents could learn about their tiny, buzzing neighbors.

“We wouldn’t have all our wildflowers that bloom every summer and fall without insects there to help do it,” Weschler said. “They’re a huge part of agriculture, forestry — literally almost any industry you can think of. Insects even have an impact on medicine. I think it’s worth knowing more about your local ecosystems and understanding and appreciating them more.”

Furthermore, Weschler pointed out that research in this field, here and everywhere, is always ongoing and that she is proud to have contributed in part to this vexing scientific question.

“A good start would be figuring out the particularly vulnerable species and species of concern. Like, are we finding debris of, say, monarchs? If that’s something that we’re finding a lot of through their migration corridors, that would be a pretty big concern, right? Monarchs are already a threatened species,” Weschler said.

Weschler herself said that she is looking forward to conducting more research within the state to determine the effects of insect abundance over the long term, which is why she took future sites of wind farms into consideration when siting her field research.

While it is hard to say now if any insect species at all are meeting their fate at an unprecedented rate through turbines in Wyoming, Weschler said that there is still much to learn. She added that she attempted to make her paper as digestible as possible so that all interested residents can learn more about the greater ecological system they inhabit. That paper can be read here.


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