The most abundant predators of the pine engraver, Ips pini (Say), include Platysoma cylindrica (Paykull) and Medetera bistriata Parent. We amended "bark sandwiches" with pine engravers and adult P. cylindrica and larval M. bistriata, and report observations on these endophytic predators. Adult P. cylindrica preferred adult prey, and appeared to be facultative egg predators, which contrasts with other Histeridae. The larvae of P. cylindrica fed on pine engraver larvae. Protection from predators is generally assumed to be an advantage of an endophytic life history, but we found that this predator exploited the herbivore's gallery architecture to facilitate prey capture. Larval M. bistriata also fed on pine engraver larvae. Immediate paralysis or death of the prey followed a strike with their tentorial rods. Such rapid immobilization, in conjuction with the glandular histology of Medetera spp., suggests that they use a toxin to arrest prey.
|Original language||English (US)|
|Number of pages||14|
|Journal||Journal of Insect Behavior|
|State||Published - Jan 2004|
Bibliographical noteFunding Information:
We thank the Wisconsin Department of Natural Resources for providing the trees and sites for insect collection. Field and laboratory assistance by S. Eastwood, R. Hoffman, J. Ludden, and G. Richards was greatly appreciated. M. Clayton, Department of Statistics, UW-Madison, provided statistical advice. J. Gruber, Department of Entomology, UW-Madison, provided valuable help with Histerinae literature. This study was supported by the U.S. Department of Agriculture (USDA NRI AMD 96 04317, USDA CSREES 2001-35302-10952), the Wisconsin Department of Natural Resources, the University of Wisconsin-Madison College of Agricultural and Life Sciences, S. C. Johnson and Son, Inc., and an Elsa and Louis Thomsen Wisconsin Distinguished Fellowship awarded to B.H.A.
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- Ips pini