PREDATOR-PREY INTERACTIONS: EXPERIMENTAL AND FIELD APPROACHES

Predator-prey interactions constitute a major ecological process, which affects individuals, populations, and communities and links various organisms within and across ecosystems. Indeed, as all heterotrophs must procure their food from other organisms, and most organisms are at some risk for becoming a food-source for others, one could argue that predation (used in the broadest sense to also include herbivory and parasitism) is the fundamental mechanism of energy exchange among organisms. In addition, some workers view predation as an important evolutionary force that may have contributed notably to the history of life over a wide range of spatial and temporal scales (e.g., Vermeij 1977, 1987, Signor & Brett 1984, Leighton 2003; but see Kowalewski et al. 2005, Madin et al. 2006). Consequently, predation has received increasing attention among paleontologists, as reflected by recent books (Kowalewski & Kelley 2002, Kelley et al. 2003) and journal theme issues (Leighton &Aronowsky 2003) devoted exclusively to the fossil record of predator-prey interactions. This theme issue represents a series of papers that bridge an important gap, which typically separates ecological research on modern biota from paleoecological research in deep time. On the one hand, all case studies included in this issue focus on modern marine shellfish and represent ecological settings and time scales. On the other, the studies target shellfish organisms representing groups that dominate the marine fossil record (molluscs, brachiopods, and arthropods), and center on processes and patterns of direct paleontological relevance. To this end, the compiled studies use the actuopaleontological approach primarily: they use modern settings and present-day organisms to augment our understanding of the fossil record and bring together neontological and paleontological perspectives. In addition, these detailed case studies also stand on their own as useful contributions to the ecological literature. The reports included here summarize seven actuopaleontological research projects conducted by graduate students who attended a 5-wk graduate-level field course conducted at Friday Harbor Laboratories (FHL) of the University ofWashington in July and August 2004. Each paper represents an individual case study developed and conducted over the period of five weeks by a single student. The papers are summarized in Table 1. They represent a diverse array of approaches, ranging from highly controlled experimental studies conducted in a laboratory setting (Fig. 1) to projects relying on field sampling and/or direct field observations (Fig. 2). The projects are also diverse in that they target a variety of predator-prey and parasite-host systems. The latter type of interactions is included here in recognition of numerous ecological and evolutionary parallels that may be shared by parasite-driven and predator-driven interactions. Finally, the studies use a variety of analytical and data collecting strategies highlighting the wealth of research strategies available to actuopaleontologists. Whereas some of the projects are somewhat preliminary in nature, which is not surprising given the stringent limitation of a 5-wk time window for data collection imposed on the students, the reports rely on rigorous quantitative data backed by statistical tests. All in all, we believe that all of these projects will prove to be useful contributions to the shellfish literature and of interest to a diverse audience, including biologists and paleontologists.