17 results
Contributors
-
- By Claude Alain, Amy F. T. Arnsten, Lars Bäckman, Malcolm A. Binns, Sandra E. Black, S. Thomas Carmichael, Keith D. Cicerone, Maurizio Corbetta, Bruce Crosson, Jeffrey L. Cummings, Deirdre R. Dawson, Michael deRiesthal, Roger A. Dixon, Laura Eggermont, Kirk I. Erickson, Anthony Feinstein, Susan M. Fitzpatrick, Fu Qiang Gao, Douglas D. Garrett, Omar Ghaffar, Robbin Gibb, Elizabeth L. Glisky, Martha L. Glisky, Leslie J. Gonzalez Rothi, Cheryl L. Grady, Carol Greenwood, Gerri Hanten, Richard G. Hunter, Masud Husain, Narinder Kapur, Bryan Kolb, Arthur F. Kramer, Susan A. Leon, Harvey S. Levin, Brian Levine, Nadina Lincoln, Thomas W. McAllister, Edward McAuley, Bruce S. McEwen, David M. Morris, Stephen E. Nadeau, Roshan das Nair, Matthew Parrott, Jennie Ponsford, George P. Prigatano, Joel Ramirez, John M. Ringman, Ian H. Robertson, Amy D. Rodriguez, John C. Rosenbek, Bernhard Ross, Erik Scherder, Victoria Singh-Curry, Trudi Stickland, Donald T. Stuss, Edward Taub, Gary R. Turner, Harry V. Vinters, Samuel Weiss, John Whyte, Barbara A. Wilson, Gordon Winocur, J. Martin Wojtowicz
- Edited by Donald T. Stuss, University of Toronto, Gordon Winocur, University of Toronto, Ian H. Robertson, Trinity College, Dublin
-
- Book:
- Cognitive Neurorehabilitation
- Published online:
- 05 September 2015
- Print publication:
- 11 September 2008, pp ix-xiv
-
- Chapter
- Export citation
3 - Theories on mutualism
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 14-56
-
- Chapter
- Export citation
-
Summary
Theories on co-operation
The theory of co-operation between kin and closely related individuals has flourished since the publication of Hamilton's C/B < r rule, stating that the relatedness (r) of an individual that profits from a co-operative (altruistic) act must be higher than the cost (C)/benefit (B) ratio this act imposes. This inclusive fitness concept is best explained by a simple example. Consider a pair of diploid brothers (r = 0.5) who share, on average, 50% of their genes. If one of them sacrifices his own fitness by not reproducing (C = 1) but helps his brother to rear his offspring successfully the following condition must be fulfilled. In order for C/B to become smaller than r the benefit for the receiver of the altruistic act must at least double before the altruist will gain representation in the next generation. Evidently, to beat the disadvantage of not reproducing when a high coefficient of relatedness is involved, low costs or large benefits are needed. As the benefit of co-operation decreases rapidly with declining relatedness, it becomes clear that the ability to discriminate between related and unrelated individuals is vital for the evolution of co-operation. Given that ants and partners of ants like aphids, lycaenids or coccids are often socially organized, relatedness is an important issue also in the co-operation between members of different species (mutualism). Therefore, it might be helpful to briefly explore the major theories and mechanisms involving co-operation/mutualism trajectories (Table 3.1).
4 - Mutualisms between ants and their partners
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 57-88
-
- Chapter
- Export citation
-
Summary
Phylogeny and feeding ecology
Ants collect liquid food from caterpillars of the families Lycaenidae, Riodinide and Tortricidae (Maschwitz et al. 1986, Hölldobler and Wilson 1990, DeVries 1991a, Pierce et al. 2002), Sternorrhyncha (scale insects, aphids, white flies), Auchenorrhyncha (cicadas, leafhoppers, planthoppers) often summarized under the term ‘Homoptera’ (Buckley 1987, Wood 1993, Gullan and Kosztarab 1997, Delabie 2001, Stadler and Dixon 2005) and Heteroptera (Maschwitz et al. 1987, Hölldobler and Wilson 1990). In addition, they collect nectar from plants (Davidson et al. 2004, Oliveira and Freitas 2004). Many of these mutualisms are facultative and unspecialized, but the common denominator of all these associations is that they are driven by sugary excreta that are attractive to ants. Otherwise the life histories of these partners of ants are highly diverse. A crude characterization of the different taxa is that Sternorrhyncha and Auchenorrhyncha are often gregarious during some stage of their development, while many butterfly larvae have a more solitary lifestyle. Dispersal may occur in the early instars, as in many coccids (crawlers), while all other partners of ants disperse as adults. The beginning of the interactions between ants and other insects, in particular between ants and homopterans, dates back to the early Tertiary, because fossils in Baltic amber suggest that associations between aphids and Iridomyrmex spp. have existed since the early Oligocene (Wheeler 1910, Hölldobler and Wilson 1990).
7 - Prospects and conclusions
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 175-183
-
- Chapter
- Export citation
-
Summary
Historically, ecology has been dominated by research on negative (antagonistic) interspecific interactions like competition and predation/parasitism. Nevertheless, this bias has led to a good understanding of the population dynamics of many species and organization of communities. In particular, the development of the theory of host–parasitoid and predator–prey dynamics was associated with experimental studies searching for mechanisms and general rules in population ecology. The advantage of studying negative interactions is that the fitness of the victim is likely to be zero, or close to zero, if eaten or parasitized. This makes it easier to track the outcome of these interactions both theoretically and experimentally. In addition, the idea of regulation is very seductive as it suggests clear relationships between predators and prey or between hosts and parasites and a simple mechanism generating population fluctuations. Mutualism, in contrast, involves reciprocal positive interactions between organisms belonging to different species and often produces less clear cut outcomes. Positive interactions tend to be diffuse, dependent on boundary conditions and thus may shift from positive to negative over time. This means that a good understanding of the conditions is necessary for quantifying the net outcome of conditional interactions. In spite of these difficulties, there is growing evidence that at least temporal positive interactions are widespread in insect communities and, in particular, between ants and their insect partners.
1 - The scope of the problem
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 1-8
-
- Chapter
- Export citation
-
Summary
The concept of natural selection proposed by Charles Darwin and Alfred Russel Wallace rests on the assumption that environmental conditions determine how well particular traits of organisms are suited for reproduction and survival. In this respect it is a conditional theory, which suggests different outcomes in different situations. That is, as long as the conditions remain the same, particular traits might continue to be adaptive and eventually become more common in a population. Changes in ecological conditions, which might be either bottom-up or top-down from the perspective of phytophagous insects, can drastically change the requirements and make previously well suited traits maladaptive. As a consequence, classifying interactions between different species as competition, predation, parasitism, mutualism, and so on risks being an oversimplification because of the ongoing changes in ecological conditions, which might continuously shift the nature and outcome of interspecific interactions. Bronstein (1994b) criticized the static view because it obscured the ecological and evolutionary links between the different interactions. In a dynamic world there are no fixed categories. However, placing interactions into different categories does help us understand at least pair-wise interactions, which, historically, have focused on competition, predation and parasitism (Kingsland 1995).
Part of the reason for the underrepresentation of mutualism in population theory and community ecology is the widespread use of classic Lotka–Volterra type models, which were developed for antagonistic associations and appear to give ‘silly’ results when the feedback is positive rather than negative.
Subject index
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 215-219
-
- Chapter
- Export citation
Preface
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp vii-viii
-
- Chapter
- Export citation
-
Summary
Mutualism, a reciprocal beneficial interaction between organisms, involves ecological and evolutionary processes occurring at several scales of organization. For many decades mutualism was the stepchild of ecology, neglected, malnourished and not studied theoretically because the prevailing paradigm was ‘nature red in tooth and claw’. Positive interactions appeared to be both more difficult to accept on theoretical grounds and to test experimentally than negative interactions. In particular, trying to understand the conditions for stability and long-term outcome of positive interactions was (and still is) a great challenge. Now it is appreciated that there exists a continuum in the interactions between individuals belonging to different species, like ants and their insect partners, and this raises several interesting questions. For example:
How can the different life histories of ants and their partners be merged so that interactions become beneficial?
How does the abundance of the partners affect the strength of these interactions?
What are the population and community consequences of mutualistic relationships for the interacting partners and indirectly affected species?
Do mutualistic interactions affect species diversity?
How does the environment affect the outcome and stability of these associations?
How can the different partners of ants coexist in local and regional communities?
How can mutualists persist in the face of exploiters?
In this book we aim to explain the underlying mechanisms of the dynamics of these associations by adopting a view that is not ant-centred, because the selection pressures of such associations are likely to affect both partners.
6 - Multitrophic-level interactions
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 107-174
-
- Chapter
- Export citation
-
Summary
Mutualism within a resource-tracking framework
Bottom-up and top-down forces
Interacting populations are subject to a host of biotic and abiotic factors, no matter whether the result of this interaction is obligate or facultative, positive or negative for the members of one or both populations. This is not new. Trophic relationships were included in the debate about the importance of resources (bottom-up) versus natural enemies (top-down) in determining population size and community structure. In addition, this food web perspective touches upon a century-old issue in ecology, which is the population regulation paradigm (Turchin 1999). This fundamental concept in ecology states that demographic density dependence is the key mechanism for population regulation. The simplest model of regulation is the logistic equation (Verhulst 1838) (for a full historical account see Kingsland 1995, Hixon et al. 2002). It is evident that natural populations do not grow unchecked, yet if and how population regulation occurs still remains an issue treated in special features in major ecological journals (Graham and Dayton 2002) and periodically resurfaces in skirmishes (Murray 1999, Turchin 1999). For example, in their highly influential paper Hairston et al. (1960) argued that in terrestrial communities, decomposers, producers and predators are resource limited ‘in the classical density dependent fashion’, while herbivores are controlled by predation; that is, they are unlikely to compete for resources. Not all agreed then and now (Power 1992, Dixon 2005).
Species index
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 212-214
-
- Chapter
- Export citation
Contents
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp v-vi
-
- Chapter
- Export citation
Frontmatter
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp i-iv
-
- Chapter
- Export citation
References
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 184-211
-
- Chapter
- Export citation
5 - A special case: aphids and ants
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 89-106
-
- Chapter
- Export citation
-
Summary
Features associated with ant attendance
Phloem sap is a poor diet because of its low nitrogen concentration, unbalanced composition, and temporal variability in quality (e.g. nitrogen or secondary metabolite content). Nitrogen is mostly present in low concentrations usually ranging between 50 and 300 mM (0.8–4.5% w/v) (Mittler 1958, Ashford et al. 2000, Sandström and Moran 2001). Intracellular aphid symbionts (Buchneria) provide their host with amino acids, which are otherwise in short supply in the phloem sap, and the symbiosis between aphids and bacteria is considered as essential for utilizing phloem sap (Douglas 1998). Adaptations to utilize this resource might offer opportunities and cause problems with respect to mutualistic interactions with ants. For example, different ant species and different groups within an ant colony have different nutritional needs at different times of the year. Workers rely on carbohydrates for their energy needs during foraging, whereas larvae require mainly nitrogenous food for growth. Like phloem sap, honeydew is a nitrogen-poor diet and, as a consequence, ants must be able to adapt to this resource. For example, some ant species harbour micro-organisms in their digestive tract, probably to supplement the liquid diet with essential amino acids and other nutrients (Roche and Wheeler 1997).
A large number of adaptations have been shown (some of which were described in previous chapters) to influence to some extent the strength of the interactions between ants and aphids, which range from positive to negative.
2 - Historical perspective
- Bernhard Stadler, Universität Bayreuth, Germany, Anthony F. G. Dixon, University of East Anglia
-
- Book:
- Mutualism
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008, pp 9-13
-
- Chapter
- Export citation
-
Summary
Compared with competition and exploitation (predation and parasitism) mutualism has been very little studied by field and theoretical ecologists. In 1986 May and Seger recorded that the ratio of papers on competition:exploitation:mutualism published in ecological journals was 4:4:1 and in terms of pages devoted to these subjects in ecological textbooks it was 5:6:1, and this marked prevalence of publications and pages in textbooks on competition and exploitation over that devoted to mutualism still prevails (Fig. 2.1).
This is surprising since a vast number of mutualistic relationships, many of which are still incompletely described, are known from nature, for example: pollinating insects, symbiotic micro-algae in corals etc., and symbiotic nitrogen-fixing bacteria. Besides these, which are fundamental for the functioning of organisms, there are many more exotic examples, for example cleaning symbioses of coral fish, associations of hermit crabs with sea anemones and luminescent bacteria with fish and cephalopods.
It is suggested that the gender bias in science may have encouraged a male view of life as a contest, ‘like a football game’ (Diamond 1978). However, there has not been a noticeable change in emphasis in this respect associated with the dramatic change in the sex ratio among biologists, as least in western societies, which has occurred since 1978. More recently Turchin (2003) suggested that more attention is devoted to competition and exploitation than mutualism because such interactions appear to be more important for population dynamics.
Mutualism
- Ants and their Insect Partners
- Bernhard Stadler, Anthony F. G. Dixon
-
- Published online:
- 13 August 2009
- Print publication:
- 07 April 2008
-
A mutualism is an interaction between individuals of two different species of organism in which both benefit from the association. With a focus on mutualisms between ants and aphids, coccids, membracids and lycaenids, this volume provides a detailed account of the many different facets of mutualisms. Mutualistic interactions not only affect the two partners, but can also have consequences for higher levels of organization. By linking theory to case studies, the authors present an integrated account of processes and patterns of mutualistic interactions at different levels of organisation, from individuals to communities to ecosystems. Interactions between ants and their insect partners and their outcomes are explained from a resource-based, cost-benefit perspective. Covering a fascinating and growing subject in modern ecology, this book will be of interest to community and evolutionary ecologists and entomologists, at both research and graduate student level.
12 - Inverse latitudinal gradients in species diversity
-
- By Pavel Kindlmann, Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, University of South Bohemia, Agrocampus Rennes, Iva Schödelbauerová, Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, University of South Bohemia, Anthony F. G. Dixon, University of East Anglia
- Edited by David Storch, Charles University, Prague, Pablo Marquet, Pontificia Universidad Catolica de Chile, James Brown, University of New Mexico
-
- Book:
- Scaling Biodiversity
- Published online:
- 05 August 2012
- Print publication:
- 12 July 2007, pp 246-257
-
- Chapter
- Export citation
-
Summary
Introduction
No single pattern of biodiversity has attracted ecologists more than the observed increase in species richness from the poles to the tropics (Pianka, 1966; Rohde, 1992; Rosenzweig & Sandlin, 1997; Gaston & Blackburn, 2000; Willig, Kaufman & Stevens, 2003; Hillebrand, 2004). An obstacle in the search for the primary cause of this latitudinal gradient is the ever-increasing number of hypotheses (Pianka, 1966; Rohde, 1992; Clarke, this volume), their interdependence (Currie, 1991; Gaston & Blackburn, 2000) and lack of rigorous falsification (Currie, Francis & Kerr, 1999; Currie, this volume). However, a general decline in species richness with latitude is commonly observed (Pielou, 1977; Colwell & Hurtt, 1994; Willig & Lyons, 1998; Colwell & Lees, 2000; Zapata, Gaston & Chown, 2003; Colwell, Rahbek & Gotelli, 2004).
Some groups of organisms, however, show an opposite trend: a strong latitudinal decline in species diversity towards the tropics. These trends have been almost neglected in the literature and little is known about their underlying ecological and evolutionary causes. Therefore, the ecological explanations proffered are usually specific to the group in question. Here an account of the most important cases of inverse latitudinal gradients is given. The existing hypotheses explaining this phenomenon are summarized and the evidence that tends to favor one of these is presented.
Looking Backward, Looking Forward: MLA Members Speak
- April Alliston, Elizabeth Ammons, Jean Arnold, Nina Baym, Sandra L. Beckett, Peter G. Beidler, Roger A. Berger, Sandra Bermann, J.J. Wilson, Troy Boone, Alison Booth, Wayne C. Booth, James Phelan, Marie Borroff, Ihab Hassan, Ulrich Weisstein, Zack Bowen, Jill Campbell, Dan Campion, Jay Caplan, Maurice Charney, Beverly Lyon Clark, Robert A. Colby, Thomas C. Coleman III, Nicole Cooley, Richard Dellamora, Morris Dickstein, Terrell Dixon, Emory Elliott, Caryl Emerson, Ann W. Engar, Lars Engle, Kai Hammermeister, N. N. Feltes, Mary Anne Ferguson, Annie Finch, Shelley Fisher Fishkin, Jerry Aline Flieger, Norman Friedman, Rosemarie Garland-Thomson, Sandra M. Gilbert, Laurie Grobman, George Guida, Liselotte Gumpel, R. K. Gupta, Florence Howe, Cathy L. Jrade, Richard A. Kaye, Calhoun Winton, Murray Krieger, Robert Langbaum, Richard A. Lanham, Marilee Lindemann, Paul Michael Lützeler, Thomas J. Lynn, Juliet Flower MacCannell, Michelle A. Massé, Irving Massey, Georges May, Christian W. Hallstein, Gita May, Lucy McDiarmid, Ellen Messer-Davidow, Koritha Mitchell, Robin Smiles, Kenyatta Albeny, George Monteiro, Joel Myerson, Alan Nadel, Ashton Nichols, Jeffrey Nishimura, Neal Oxenhandler, David Palumbo-Liu, Vincent P. Pecora, David Porter, Nancy Potter, Ronald C. Rosbottom, Elias L. Rivers, Gerhard F. Strasser, J. L. Styan, Marianna De Marco Torgovnick, Gary Totten, David van Leer, Asha Varadharajan, Orrin N. C. Wang, Sharon Willis, Louise E. Wright, Donald A. Yates, Takayuki Yokota-Murakami, Richard E. Zeikowitz, Angelika Bammer, Dale Bauer, Karl Beckson, Betsy A. Bowen, Stacey Donohue, Sheila Emerson, Gwendolyn Audrey Foster, Jay L. Halio, Karl Kroeber, Terence Hawkes, William B. Hunter, Mary Jambus, Willard F. King, Nancy K. Miller, Jody Norton, Ann Pellegrini, S. P. Rosenbaum, Lorie Roth, Robert Scholes, Joanne Shattock, Rosemary T. VanArsdel, Alfred Bendixen, Alarma Kathleen Brown, Michael J. Kiskis, Debra A. Castillo, Rey Chow, John F. Crossen, Robert F. Fleissner, Regenia Gagnier, Nicholas Howe, M. Thomas Inge, Frank Mehring, Hyungji Park, Jahan Ramazani, Kenneth M. Roemer, Deborah D. Rogers, A. LaVonne Brown Ruoff, Regina M. Schwartz, John T. Shawcross, Brenda R. Silver, Andrew von Hendy, Virginia Wright Wexman, Britta Zangen, A. Owen Aldridge, Paula R. Backscheider, Roland Bartel, E. M. Forster, Milton Birnbaum, Jonathan Bishop, Crystal Downing, Frank H. Ellis, Roberto Forns-Broggi, James R. Giles, Mary E. Giles, Susan Blair Green, Madelyn Gutwirth, Constance B. Hieatt, Titi Adepitan, Edgar C. Knowlton, Jr., Emanuel Mussman, Sally Todd Nelson, Robert O. Preyer, David Diego Rodriguez, Guy Stern, James Thorpe, Robert J. Wilson, Rebecca S. Beal, Joyce Simutis, Betsy Bowden, Sara Cooper, Wheeler Winston Dixon, Tarek el Ariss, Richard Jewell, John W. Kronik, Wendy Martin, Stuart Y. McDougal, Hugo Méndez-Ramírez, Ivy Schweitzer, Armand E. Singer, G. Thomas Tanselle, Tom Bishop, Mary Ann Caws, Marcel Gutwirth, Christophe Ippolito, Lawrence D. Kritzman, James Longenbach, Tim McCracken, Wolfe S. Molitor, Diane Quantic, Gregory Rabassa, Ellen M. Tsagaris, Anthony C. Yu, Betty Jean Craige, Wendell V. Harris, J. Hillis Miller, Jesse G. Swan, Helene Zimmer-Loew, Peter Berek, James Chandler, Hanna K. Charney, Philip Cohen, Judith Fetterley, Herbert Lindenberger, Julia Reinhard Lupton, Maximillian E. Novak, Richard Ohmann, Marjorie Perloff, Mark Reynolds, James Sledd, Harriet Turner, Marie Umeh, Flavia Aloya, Regina Barreca, Konrad Bieber, Ellis Hanson, William J. Hyde, Holly A. Laird, David Leverenz, Allen Michie, J. Wesley Miller, Marvin Rosenberg, Daniel R. Schwarz, Elizabeth Welt Trahan, Jean Fagan Yellin
-
- Journal:
- PMLA / Publications of the Modern Language Association of America / Volume 115 / Issue 7 / December 2000
- Published online by Cambridge University Press:
- 23 October 2020, pp. 1986-2078
- Print publication:
- December 2000
-
- Article
- Export citation