William Snyder

Entomology
Exploring the Relationship Between Predator Biodiversity and Biological Control

William Snyder

As agricultural producers move away from the widespread use of broad-spectrum insecticides, the abundance and biodiversity of on-farm arthropod communities is increasing. Agroecologists have long suspected that greater natural enemy biodiversity will lead to more effective pest suppression, but little experimental work has explicitly examined this assumption. In two cropping systems, potatoes and collards, we have been manipulating species richness among the community of natural enemies attacking aphids, to measure the importance of predator species diversity for effective biocontrol. We have borrowed experimental designs from the “biodiversity-ecosystem functioning” literature that isolate the importance of species diversity per se from any confounding influence of predator abundance, species identity, or community composition. The photo above is of a large-scale field experiment where predator diversity was manipulated. Interestingly, in potatoes natural enemy biodiversity seems to have no consistent benefit for aphid control, while on collards biological control always improves when natural enemy communities include multiple species.

The differing importance of predator biodiversity on potatoes versus collards suggests that plants mediate predator biodiversity effects. I am interested in examining how differences in plant structure, and differences in herbivore community diversity, exert a bottom-up influence on predator diversity’s importance for pest control. Our predator biodiversity work thus far has included only arthropod predators, but we now know that insect pathogens in the soil are key natural enemies of many herbivores. We are beginning to examine the relative importance for herbivore control of below- versus above-ground natural enemy biodiversity.

Contact Information
William E. Snyder, Ph.D.
Associate Professor
Department of Entomology

Washington State University
PO Box 646382
Pullman, WA 99164-6382

Telephone: 509-335-3724
E-mail: wesnyder@wsu.edu

Health and Life Sciences

William Snyder

Dr. William E. Snyder, associate professor in the Department of Entomology at Washington State University, received his B.A. in biology from the University of Delaware in 1992, his M.S. in zoology from Clemson University in 1995, and his Ph.D. in entomology from the University of Kentucky in 1999. He was awarded a USDA-NRI fellowship to support his postdoctoral work in the zoology department at the University of Wisconsin from 1999-2000, after which he joined the entomology department at WSU. Dr. Snyder works at the interface between basic and applied ecology, and he has been supported by grants from diverse sources including the NSF, EPA, and USDA. He currently serves on the editorial boards of the journals Ecology and Biological Control and had key recent publications appear in Ecology Letters and in Ecology.

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