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Student Research Spotlight - Rachel McLaughlin

Posted: May 20, 2019

This is the 7th of eight short news articles written by students, during the professional development class, about each other's research.

Cherry they going? The decline in black cherry trees and the search for their pollinators
By Brooke Lawrence

Look there, in the tree tops! Who’s that? What is she doing sitting in a lift in the forest canopy? That is Rachel McLaughlin, an Entomology PhD student from Penn State, and she is trying to discover the pollinators of black cherry trees.

Pennsylvania’s black cherry trees are the finest in the country, but there have been fewer seedlings and saplings in the last 20 years. The cause of this decline remains a mystery. One possible explanation is a decline in the pollinators of black cherry is leading to reduced seed production, since it is an insect-pollinated tree. This is where McLaughlin and her research come in. McLaughlin is investigating what the pollinators of black cherry trees are and how their abundance affects seed production.

Discovering the mysterious black cherry pollinators is a complicated challenge. McLaughlin needs to find out which insects are visiting flowers 20 to 50 feet above her head. She plans to suspend traps in the tree canopy to catch examples of the insects present in the trees. But she also needs to see for herself which insects are performing important pollination duties. A lift will give McLaughlin a perch high in the tree tops, where she can watch the flowers and the pollinators that visit them.

Traps laid in 2018 indicated the likely type of insect pollinating black cherry: flies. McLaughlin points out that “flies are often a forgotten group of pollinators and linking them to such a valuable tree is exciting.”

Before Penn State, McLaughlin studied pollinators in urban habitats and developed an interest in pollinator ecology. The black cherry project presented a new challenge and a way to explore her other research interests. McLaughlin notes, “I was inspired by my forestry minor to extend my research beyond urban habitats and into the forestland. When I learned about the problem in regeneration of black cherry, and the lack of knowledge surrounding its pollinators, I felt like it was the ideal project for me.”

McLaughlin is well on her way to addressing the problems with black cherry trees. But until she has the answers she’s looking for, keep an eye on the tree tops. You might get to spot a forest entomologist at work.