Across the United States, climate change is complicating many environments and biological life cycles. A Washington State University study has found ticks, a common, if often reviled insect, may be far more resilient to changing environments than previously thought.
Jesse Brunner is an associate professor at Washington State University and lead author of the study recently published in Ecological Monographs.
In the Department of Defense funded study, he worked with a team to observe 9,000 blacklegged ticks over three years. The insects, which often carry dangerous that can cause illness like Lyme disease, were trapped in soil core enclosures across several East Coast military bases. The enclosures were designed to mimic conditions in the wild.
They found that ticks are vulnerable to cold, heat or dry conditions, only when they’re in their larval stage. That’s when they are about the size of a poppy seed. Tick larvae often die when exposed to extreme conditions. But the adults usually survive environmental changes.
“We expected the ticks to be really sensitive to climatic conditions, and we found that overall, they're really not,” Brunner said. “It was just that one little stage in their life cycle where they were sensitive. And again, we will see how much that has an impact on tick populations overall, but my suspicion, that in a lot of places, climate doesn't do that much to them.”
He said the research team is working on more modeling and will eventually publish another study looking at potential population outcomes. He said heat may kill some larvae, but it’s still difficult to know how much that would change overall tick populations.
“Climate change effects all aspects of a system,” Brunner said. “From the hosts, to the environmental suitability, to the speed at which the ticks, or other vectors develop, so there's a lot of things that are changing, and trying to predict how it’s all going to play out is complicated. It’s really exciting as a biologist, but it’s really scary from a public health perspective, because it’s really hard to know what's going to happen.”
