PS 30-161 - Multi-method sampling of ground and canopy-dwelling insects in temperate deciduous trees

Tuesday, August 8, 2023

5:00 PM – 6:30 PM PDT

Location: ESA Exhibit Hall

Presenting Author(s)

BH

Brianna Hoffman

Undergraduate Student
Washington & Jefferson College
Mcmurray, Pennsylvania, United States

Coauthor(s)

Jason S. Kilgore, PhD

Professor
Department of Biology, Washington & Jefferson College
Washington, Pennsylvania, United States

Abstract:

Individual trees provide a range of niche habitats from the ground into the canopy. Research conducted in temperate forest canopies suggests that biodiverse insect communities do exist but remain understudied, especially when compared to tropical regions. Therefore, we are investigating the change in insect community from the ground to the canopy in temperate deciduous trees.

As part of a developing collaboration called ARBOREAL between faculty members, undergraduate students, and professional arborists dedicated to temperate forest canopy research, we developed and piloted protocols to survey canopy- and ground-dwelling insect biodiversity in deciduous trees. In Fall 2022, we used a large pin oak (Quercus palustris) on a college campus to practice stationary-rope climbing and maneuvering, to perform diurnal sweep net surveys, and to conduct nocturnal surveys using a suspended blacklight bucket trap. We also selected a large northern red oak (Q. rubra) in a mesophytic forest in southwestern Pennsylvania to survey ground-dwelling insect communities using a modified NEON pitfall trap protocol. Pitfall traps were located at randomly selected spots within the canopy dripline surrounding the base of the tree at each cardinal direction. All insects were identified to the lowest possible level of taxonomy.

A diversity of ground beetles, field crickets, and little black ants were collected in the pitfall traps, while moths, grasshoppers, katydids, crickets, and beetles were captured in the nocturnal blacklight trap; due to recent cold weather, no insects were captured during the diurnal sweep net survey. Pitfall traps were the most consistent and easily deployed method, with no climbing skills required. Diurnal sweep net surveys require training, practice, and supervision in tree climbing and maneuvering; however, lower branches and smaller trees could be more accessible with a telescoping net from the ground. Suspended bucket or panel traps, whether diurnal or modified with blacklights for nocturnal use, could be implemented from the ground with accurate throwline placement, sturdy branches, and bark/cambium protection, yet these systems should focus on minimizing total weight for ease of transport, deployment, and retrieval. Further, selection of lures and material color are important considerations for diurnal and nocturnal suspended insect traps. A combination of methods will be required to adequately survey and thus demonstrate the stratification and biodiversity of insect communities in temperate forest trees.