No abstract

Predation on spruce-budworm, Choristoneura fumiferana (Clem.), pupae on the forest floor was estimated at 72.5% per day. It is unlikely that many adults of the spruce budworm emerge from the forest floor and there would be little bias introduced in the estimation of apparent fecundity by disregarding pupae on the ground. There were large seasonal fluctuations in the rate of predation attributable to various predator groups; the overall rate ranged from 66 to 91% per day. Low temperatures had no detectable effect on vertebrate predation, but reduced invertebrate predation; however, this effect is unlikely to result in much variation in survival of pupae on the forest floor.

I want to thank my committee chair, Michael Weber, and my committee members, Clay Pierce, and Stephen Dinsmore, for their guidance and mentorship during my studies here at Iowa State University. I would also like to thank Michael Siepker, with the Iowa Department of Natural Resources, for his assistance with the project design and implementation. None of this project would have been possible without partial funding from the U.S. Fish and Wildlife Service and Iowa Department of Natural Resources. Others within Trout Unlimited and the University of Wisconsin at Stevens Point, are deserving of recognition for their assistance with various aspects of project completion.