This professor’s insect collection will help measure ecosystem health across the continent

Mary Mulcahy, associate professor of biology at the University of Pittsburgh at Bradford, spent her summer collecting insects to provide information for two studies gathering baseline information that will help researchers measure how insects are faring in different areas.

For the first study, on the insects needed for a healthy tree swallow population across North America, Mulcahy and Denise Piechnik, former associate professor of biology at Pitt-Bradford, joined the North American Insect Abundance Network, a group of 80 researchers across the continent conducting a longitudinal study on insect abundance.

The network’s study, now in its sixth year, has shown a decline in insect abundance, but newly recruited researchers are fine-tuning findings like the degree of insect decline and potential causes of differences in abundance.

Each researcher uses a special insect trap that looks a bit like a pup tent hovering a few feet above the ground. Researchers are assigned three different 72-hour periods, based on when swallows are expected to lay eggs, when the eggs hatch and when the nestlings are 12 days old — all times when the birds need more nutrients to support laying eggs and feeding their young.

Once the insects were gathered from her trap at the University’s West Washington Street practice field, Mulcahy had to sort and weigh them by order: beetles, moths, flies, etc. She said most of her specimens were flies. She then reported the measurements to the study’s principal investigator, Peter Dunn, an emeritus professor at the University of Wisconsin.

“It was quite a challenge,” Mulcahy said. “It was a heavier lift than I expected.”

The University will be able to keep the flies of her labor, however. Students can use them to practice extracting DNA and looking for genetic markers, she said.

Students are also benefiting from Mulcahy’s involvement with the Pennsylvania Bee Monitoring Program, which she became involved with through her designation as a Master Gardener. Master Gardeners support Penn State Extension’s education programs by volunteering in a variety of ways, including by participating in citizen science projects such as the bee study.

This is Mulcahy’s fourth year collecting the important pollinators for the study, and this year two students collected alongside her: Aiden Minch-Hick, a pre-medicine student from Mingo Junction, Ohio, and Shaun Wu, a biology major from Barrigada, Guam.

“I have always been interested in the environmental side of biology,” Minch-Hick said. “When the opportunity arose to work with the pollinators, I thought it would be great to focus on some of my other interests before I spend the rest of my academic career involved in health care.

“The time I’ve spent in the field with Dr. Mulcahy has been wonderful. She does such a great job of elaborating on all of the pollinators and plant species that we have come across.”

Mulcahy travels each year for training in how to collect the bees according to the study’s research protocol, which ensures all samples are collected in the same manner and can be compared and contrasted from year to year.

She said there are more than 400 species of bees in Pennsylvania alone, something even she didn’t know before taking part in the project.

“As much as I have studied pollinators, I didn’t really appreciate that most of them are smaller than honeybees,” she said. An inspection of her samples stored in alcohol reveals that many of the bees also don’t exhibit the black and yellow stripes associated with them.

To collect the bees, Mulcahy and the students placed bee bowls in colors that attract the insects in places where they had secured permission to do so, including on Pitt-Bradford’s Quintuple Mountain property and near its pollinator garden, in state parks and on land overseen by the Western Pennsylvania Conservancy. She and her students are the only team to have collected in the northcentral portion of the state.

The bowls hold water and a little bit of dish soap, and the bees that land in the bowls do die. But Mulcahy says this method can collect smaller bees, the health and population of which are important to track.

“There are all of these amazing different bees,” she said, “and they’re doing a lot of pollinating.”

After capturing the bees, Mulcahy and the students categorized and sent them to the Bee Monitoring Program, where they are used to monitor the health of the state’s bee populations and become part of natural history collections where they can be studied further. She likes the idea of her and her students’ bees with their tiny tags finding a home in the Frost Entomological Museum at Penn State, where they can continue to contribute to science.

— Kimberly Marcott Weinberg, photography by Glenn Melvin. In the top photo, Aiden Minch-Hick and Mary Mulcahy captured bees on Pitt-Bradford’s campus for the Pennsylvania Bee Monitoring Program in June.