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Shepherd stink bug research shows native predators will destroy eggs

By Staff | May 23, 2016

The journal Biological Control has published a paper on brown marmorated stink bug (BMSB) research that a Shepherd University professor and students helped conduct. The article, titled “Frequency, efficiency, and physical characteristics of predation by generalist predators of brown marmorated stink bug (Hemiplera: Pentatomidae) eggs” by William R. Morrison III, Clarissa R. Mathews and Tracy C. Leskey, will appear in the June issue of the journal.

Mathews, the chair of Shepherd’s Institute of Environmental and Physical Sciences, and four Shepherd students and alumni helped conduct the research, which they nicknamed stink bug CSI. Current Shepherd students majoring in environmental studies, McKenzie Allen, from Kearneysville and Hector Nevarro-Guitz, from Shepherdstown, along with alumni Brittany Poling and Morgan Douglas, worked on the project, which was funded in part by USDA NIFA Organic Research and Extension Initiative.

Brown marmorated stink bugs are native to Asia and a few years ago their population exploded, causing great economic harm to local farmers and orchardists. Initially it appeared there were no natural predators to control the bugs. This study looked at whether predators that are generally found at mid-Atlantic orchards and farms, like katydids, beetles, earwigs and spiders, will eat stink bug eggs.

“This is the first time for this type of study,” Mathews said. “One of the surprising findings was that there are some natural predators in our local environment that are doing a good job of eating stink bug eggs.”

From May to September in 2014 and 2015, the researchers captured many of the predators at Red Bud Farm in Berkeley County or at the U.S. Department of Agriculture Appalachian Fruit Research Laboratory in Kearneysville. They also obtained some predators from commercial biological control companies.

The predators were given access to only water for one day, and then were placed in a container with a mass of stink bug eggs. Mathews and the students magnified and documented through photography and video whether the predators ate the eggs and how they ate them.

“The most surprising group was the katydid,” Mathews said. “The katydids are really good predators of the eggs. They devoured all the eggs in the egg mass and left no residue behind whatsoever. In fact, sometimes the katydids even ate the card the egg mass had been laid on.”

Mathews said another surprising predator was the jumping spider (Salticidae). They punctured the eggs with their chelicerae, a part on the spider’s mouth that allows it to puncture something and suck out the contents.

“They were not very efficient though,” Mathews said. “They had to do this over a long period of time, so they were not good predators like the katydids. They could not attack all 28 eggs, for instance.”

Mathews said one surprise from the research was that lady beetles (Coccinellidai) are not good stink bug egg predators. While lady beetles eat a variety of other types of eggs, they didn’t seem to like those from the stink bug. Mathews said the ground beetle (Carabidae), found stink bug eggs tasty, though.

“Ground beetles are ubiquitous in agricultural fields, so that was a good indicator that we have another species or group of insects that could be helping in the fields,”” she said.