Citation. Craig, T. P. 1994. Effects of intraspecific plant variation on parasitoid communities. Pages 205-227 in B. A. Hawkins and W. Sheehan, Eds., Parasitoid Community Ecology. Oxford University Press, Oxford, UK.   [1028  LTERCC]

Introduction. The importance of tritrophic interactions was first brought to the attention of ecologists by the work of Price et al. (1980). Since that time a plethora of studies in a wide range of plant-herbivore-parasitoid systems have confirmed the importance of tritrophic interactions in shaping the population dynamics of these systems (Barbosa and Letourneau 1988; Hare 1992). Since tritrophic interactions can influence the population biology of individual parasitoids it is logical that tritrophic level interactions can structure parasitoid communities, but this possibility has not been extensively studied. The simplest system in which to examine the effect of tritrophic interactions on community structure is to look at the parasitoids of a monophagous herbivore. The goal of this chapter is to examine how tritrophic level interactions structure the parasitoid community of the monophagous, gall-forming sawfly, Euura lasiolepis Smith. I will document in detail how variation in the environment and the host plant can have impacts that 'cascade up' (sensu Hunter and Price 1992) to influence the parasitoid community of E. lasiolepis. Evaluation of the role of these effects coming from below on parasitoid community structure has been neglected, as we have only a limited knowledge of how environmental variation and plant characteristics influence parasitoid communities (Hawkins 1992; Hunter and Price 1992).