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, Marlin 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 of Washington 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.
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CASE STUDIES--A THEMATIC SYNOPSIS
The papers compiled here include seven case studies that range from laboratory experiments to field observations, and target diverse shellfish organisms, including bivalve molluscs, gastropods, crustacean arthropods, and brachiopods (Table 1).
The first three papers published in this volume (Bulinski 2007, Willman 2007, Cintra-Buenrostro 2007) represent experimental studies (Fig. 1), with targeted organisms isolated in controlled settings. Bulinski (2007) reports experimental data that quantitatively evaluate effects of isolation, competition, and predation on shell selection behaviors of the hermit crab Pagurus granosimanus. This study utilizes a series of seawater tank experiments focused on hermit crabs that were first stripped of the shells they originally inhabited when collected and then offered a choice of multiple, empty gastropod shells damaged to various degrees. Bulinski's study highlights potential secondary effects of predators, which can affect prey behavior indirectly; that is, the mere presence of the predator and related threat risk alters behavior of the prey. Willman (2007) uses artificial spines attached to valves of the mussel Mytilus trossulus to test if such armor can provide an effective defense system against, or alter the behavior of, the muricid gastropod Nucella lamellosa. The author demonstrates diverse (and sometimes counterintuitive) effects of spines on the nature of predator-prey interactions. Cintra-Buenrostro (2007) combines field and experimental approaches to establish a clear-cut distinction between shell damage induced by predatory crabs versus that induced by postmortem mechanical processes. Using shells of the mussel Mytilus trossulus, the author contrasts and compares damage patterns induced by crab predation versus mechanical tumbling and trampling. This study provides useful quantitative and qualitative standards for identifying shell damage induced by predators and offers methodological guidelines for future experimental and observational studies.
The other four studies included here (Koy 2007, Huntley 2007, Rodrigues 2007, Stempien 2007) focus on observational data collected in various intertidal and subtidal habitats near Friday Harbor (Fig. 2). This series of papers is opened by a brief note by Koy (2007) who reports on several specimens of the gastropod Nucella lamellosa abandoning their shells during, or soon after, collection. Koy explores consequences and potential implications of this extremely unusual and unexpected snail behavior. Huntley (2007) details a quantitative study on parasite-host interactions based on numerous specimens of the bivalve Protothaca staminea live-collected from an intertidal setting. This study provides useful estimates on the intensity of parasitic infestation in local bivalves' host populations, explores relations between host's mode of life and the type and intensity of host-parasite interactions, and offers practical paleontological guidelines for identifying parasitic infestations in the fossil record of benthic molluscs. Using a similar approach, Rodrigues (2007) examines biotic interactions between brachiopods and spionid polychaete worms quantitatively, based on material dredged from subtidal environments around the San Juan Islands (USA). A detailed description of traces left by infesting organisms, enhanced by numerical data on infestation frequency, highlights the importance of this biotic interaction for modern shellfish and provides actualistic guidelines for studying the fossil record of parasite-host interactions in the fossil record of brachiopods. Finally, Stempien (2007) combines field samples and field observations to evaluate the effect of avian predation on intertidal mollusc-dominated communities. This study provides multiple qualitative and quantitative criteria for detecting bird predation indirectly via non-invasive sampling of surficial shell assemblages. The study also illustrates the possible biases that may affect the fossil record of benthic shellfish caused by selective, and often destructive, avian predation.
The brief synopsis serves primarily to highlight the diversity of topics and approaches encompassed within this theme issue. However, intentionally, we have not disclosed here any specific conclusions that are presented in those case studies. These conclusions belong to their authors and the readers will need to go beyond the pages of this introduction to learn more. This will be, we believe, well worth your time!
Finally, we emphasize that the research success of this course reflects chiefly two factors. First, it reflects the perseverance and intellectual abilities of the involved students who, despite numerous other obligations, have invested many additional weeks after the course was over to complete analyses, manuscripts, and revisions. Second, the success of the projects reflects the truly exceptional research environment that is provided by Friday Harbor Laboratories. The wide spectrum of marine settings available for sampling and field observations around San Juan Islands, the abundant and diverse marine benthic faunas of the area, and the extensive laboratory facilities available at the laboratories make the FHL campus one of the foremost nursing grounds for training future generations of biologists and paleontologists interested in marine shellfish prey and their enemies.
The authors thank the Friday Harbor Laboratories for generous logistic support during and after the course and for providing financial support toward the publication of this volume. The authors also thank the FHL faculty and staff for unwavering support and patience and for creating and nurturing (so successfully!) the intellectually rewarding and uniquely collegial working environment that summer instructors and their students can enjoy so much at the Friday Harbor Labs. The teaching assistants, Richard A. Krause and Jennifer Stempien (Ph.D. students at Virginia Tech at the time of our course), contributed greatly to the success of the course and to the success of individual students by facilitating day-to-day research activities and offering continuous intellectual and moral support to everyone. The authors are greatly indebted to Sandy Shumway, the editor of the Journal of Shellfish Research, whose editorial expertise, support, and logistic diligence aided them greatly in the assembly and preparation of the papers included here. The authors also owe a great deal of gratitude to numerous reviewers who provided detailed and constructive reviews and helped their students to refine and improve the overall quality of their papers. Last but not least, the authors thank all the students for their perseverance and enthusiasm that made the field course so enjoyable for them and this special issue possible.
Bulinski, K. V. 2007. The shell-selection behavior of hermit crabs in isolation, competition, and predatory settings. J. Shellfish Res. 26:233-239.
Cintra-Buenrostro, C. E. 2007. Trampling, peeling and nibbling mussels: an experimental assessment of mechanical and predatory damage to shells of Mytilus trossulus (Mollusca: Mytilidae). J. Shellfish Res. 26:221-231.
Huntley, J. W. 2007. Towards establishing a modern baseline for paleopathology: Trace-producing parasites in a bivalve host. J. Shellfish Res. 26:253-259.
Kelley, P. H., M. Kowalewski & T. A. Hansen, editors. 2003. Predator-Prey Interactions in the Fossil Record (Topics in Geobiology Series 20). New York: Plenum Press/Kluwer. pp. 464.
Kowalewski, M. & P. H. Kelley, editors. 2002. The Fossil Record of Predation (Paleontological Society Special Papers 8). New Haven, CT: Yale Printing Service. pp. 398.
Kowalewski, M., A. P. Hoffmeister, T. K. Baumiller & R. K. Bambach. 2005. Secondary evolutionary escalation between brachiopods and enemies of other prey. Science 308:1774-1777.
Koy, K. A. 2007. Shell-less Nucella lamellosa (Gmelin) from the rocky intertidal of San Juan Island, WA. J. Shellfish Res. 26:267 269.
Leighton, L. R. 2003. Morphological response of prey to drilling predation in the Middle Devonian. Palaeogeogr. Palaeoclimatol. Palaeoecol. 201:221 234.
Leighton, L. R. & A. Aronowsky. 2003. Exciting research on boring predation. Palaeogeogr. Palaeoclimatol. Palaeoecol. 201:183-184.
Madin, J. S., J. Alroy, M. Aberhan, F. T. Fursich, W. Kiessling, M. A. Kosnik & P. J. Wagner. 2006. Statistical independence of escalatory ecological trends in Phanerozoic marine invertebrates. Science 312:897-900.
Rodrigues, S. C. 2007. Biotic interactions recorded in shells of recent Rhynchonelliform brachiopods from San Juan Island, USA. J. Shellfish Res. 26:241-252.
Signor, P. W. & C. E. Brett. 1984. The mid-Paleozoic precursor to the Mesozoic marine revolution. Paleobiology 10:229-245.
Stempien, J. 2007. Detecting avian predation on bivalve assemblages using indirect methods. J. Shellfish Res. 26:271-280.
Vermeij, G. J. 1977. The Mesozoic marine revolution: Evidence from snails, predators, and grazers. Paleobiology 3:245-258.
Vermeij, G. J. 1987. Evolution and Escalation, an Ecological History of Life. Princeton, Princeton University Press. pp. 527.
Willman, S. 2007. Testing the role of spines as predatory defense. J. Shellfish Res. 26:261-266.
TABLE 1. A summary of case studies on predator-prey and parasite-host interactions included in this theme issue. All studies were conducted at Friday Harbor Laboratories as a part of the 5-wk field course in July and August 2004. Targeted Shellfish Reference Title Organisms Experimental Studies Bulinski (2007) The shell-selection Pagurus granosimanus behavior of hermit (Arthropoda) crabs in isolation, competition, and predatory settings Willman (2007) Testing the role of Mvtilus trossuhts spines as predatory (Mollusca) defense Cintra-Buenrostro Trampling, peeling Mytilus trossulus (2007) and nibbling mussels: (Mollusca) an experimental assessment of mecha- nical and predatory damage to shells of Mytilus trossulus (Mollusca: Mytilidae) Observational Studies Koy (2007) Shell-less Nucella Nucella lamellosa lamellosa (Gmelin) from the rocky (Mollusca) intertidal of San Juan Island, WA Huntley (2007) Towards establishing a Protothaca staminea modern baseline for (Mollusca) paleopathology: Trace-producing parasites in a bivalve host Rodrigues (2007) Biotic interactions Terebratalia transver- recorded in shells of sa (Brachiopoda) recent Rhynchonelli- form brachiopods from San Juan Island, USA Stempien (2007) Detecting avian preda- multiple mollusc tion on bivalve species assemblages using indirect methods Primary Approach Primary Data Reference Used Type Experimental Studies Bulinski (2007) Laboratory Experiments Quantitative Willman (2007) Laboratory Experiments Quantitative Cintra-Buenrostro Laboratory and Field Quantitative (2007) Experiments Observational Studies Koy (2007) Laboratory Observations Qualitative Huntley (2007) Field Observations Quantitative (intertidal) Rodrigues (2007) Field Observations Quantitative (subtidal) Stempien (2007) Field Observations Quantitative (intertidal)
MICHAL KOWALEWSKI (1) * AND LINDSEY R. LEIGHTON (2)
(1) Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061; (2) Department of Geological Sciences, San Diego State University, San Diego, California 92182
* Corresponding author: E-mail: email@example.com.
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|Title Annotation:||SPECIAL THEME SECTION|
|Author:||Leighton, Lindsey R.|
|Publication:||Journal of Shellfish Research|
|Date:||Apr 1, 2007|
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