Pursuing a passion

By EVE NEWMAN

The mountain pine beetle epidemic that swept through the area a few years ago has left its mark, with thousands of acres of trees dead and dying across southeast Wyoming.

The beetle’s population has declined locally, but scientists are continuing to study the tiny insect in preparation for the next epidemic.

A University of Wyoming graduate student is hoping to shed light on the beetle’s natural predators while also improving the methods used to study the beetle.

“The bark beetle and its natural enemies spend most of their life cycle under the bark of trees,” said Larry Haimowitz, who is working on a master’s degree. “It’s an enormously difficult system to study. It’s very difficult to figure out a way to get at the information you want about these insects when most of what’s taking place is taking place inside the bark of a standing trees.”

Adult mountain pine beetles emerge from a host tree in the summer to look for a new tree in which to nest. In attacking a tree, a group of beetles tunnels into the bark to lay their eggs, which emerge as adults in summer.

Beetles have several natural enemies that often share the tree, including clerid beetles, long-legged flies and parasitoid wasps. They are also preyed upon by woodpeckers.

Haimowitz, who is studying entomology as a second career after retiring a few years ago, said traditional methods for studying the beetle and its natural enemies are labor-intensive while also requiring scientists to make statistical inferences about their results.

For example, cutting down a tree and peeling off the bark to look for insects provides information about the present population, but not about insects that have already left the tree.

Another method involves layering the tree in opaque cloth with a glass jar at the only exit. When an insect exits the tree, it then flies to the light it sees and is captured in the jar. Haimowitz said the cloth layer could change the temperature of the tree because it prevents both light and air from reaching the trunk.

“You’ve probably altered the thermal environment the insects are in,” he said. “Insects are cold-blooded, and if you alter that, you’ll alter their lifecycle.”

Beetles are also good chewers, and cloth doesn’t stand a chance if they’re determined to get through.

For the last several years, Haimowitz has been working on an enclosure that allows air and light to reach the trunk while keeping insects of all sizes contained after they emerge. To solve those problems, he’s been using a very fine screen made of brass, which resists rust and insects.

He used the material to conduct an experiment in which he kept all insects out of a section of a tree and then manually infected it with just beetles. Another section of the tree was infected with beetles and their predators.

The following year, he compared how many beetles emerged from the tree where they had been separated from their predators, compared to the section where they were not protected from their predators.

“There were 90-99 percent fewer beetles coming out of the unprotected segment,” he said.

Haimowitz said his methods for predator exclusion and capturing insects could be used to validate research done with other methods and less certain results.

“Validation is very important in scientific work,” he said.

As well, the methods could be used for continued study of mountain pine beetle predators and the role they play in preventing or moderating epidemics. It’s an area of study with many unanswered questions.

His work, conducted in local areas such as Pole Mountain, involves a current ecosystem with a surplus of predators and a low-level beetle population as the epidemic subsides. No one has conducted similar research during an active epidemic.

“I think natural enemies do have an effect on the severity of epidemics — even low-level mortality has an effect,” he said.

Haimowitz followed a winding career path before arriving at UW. He dropped out of college the first time he attended and worked as a welder. He returned to college when he was 30, planning to become a park ranger. As part of the degree, he took an introductory course in entomology.

“I liked it so much and I was so fascinated by it that I switched my major to entomology,” he said.

After graduating from San Jose State, he worked in occupational safety. He later met and married Laramie resident Robin Hill and moved to Wyoming. Hill introduced him to Scott Shaw, an entomology professor in the Department of Ecosystem Science and Management. Upon retiring, Haimowitz decided to go back to school once again.

Shaw said he’s enjoyed working with Haimowitz.

“He’s an exceptional researcher,” he said.

Haimowitz isn’t the first graduate student Shaw has worked with to enter the field as a second career, perhaps because the field has a draw on people.

“Entomology is a discipline that people tend to go into only when they have a passion for it,” Shaw said.

Haimowitz, who plans to work on a Ph.D. after he finishes his master’s degree, said he’s continually fascinated by the complexity and enormity of the insect world.

“There are millions of stories, and each one is intertwined with thousands of other stories, and those stories are something you’re not even aware of,” he said.

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