An experimental analysis of competitive indeterminacy in Tribolium.

Mertz, David B.; Cawthon, D. A.; Park, Thomas

doi:10.1073/pnas.73.4.1368

Cited by 41 publications

(38 citation statements)

References 17 publications

(29 reference statements)

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“…Competitive interactions initiated with approximately equal numbers of both species have indeterminate outcomes because chance events can push the system either into the region where T. confusum is favored, or into the region where T. castaneum is favored. This hypothesis is consistent with, and hence may be identified with, the region of the LotkaVolterra parameter space where the final outcome is dependent on the initial species abundances (a12 > a22 and a21 > all), if we keep in mind the fact that the line of indeterminacy in the Lotka-Volterra model becomes a zone of indeterminacy in models that allow for stochastic variation in the birth and death rates (Park et al, 1964;Mertz et al, 1976;Leslie, 1958).…”

Section: Laboratory Studies Of Competitionsupporting

confidence: 53%

“…The experimental data supporting these two ecological hypotheses are equivocal and are reviewed by Mertz (1972), and Mertz et al (1976). I will describe the experimental results of Mertz et al here, as certain oftheir results are inconsistent with both the demographic stochasticity and genetic founder effect hypotheses.…”

Section: Laboratory Studies Of Competitionmentioning

confidence: 79%

“…The following discussion of competitive indeterminacy has three main elements: First, I associate the two classical explanations ofcompetitive indeterminacy, the demographic stochasticity and genetic founder effect hypotheses, with regions of the Lotka-Volterra parameter space. Second, empirical results of Mertz et al (1976) that are inconsistent with both classical hypotheses are discussed. Third, the isomorphism between the Lotka-Volterra and coevolutionary models is used to construct two new hypotheses.…”

Section: Laboratory Studies Of Competitionmentioning

confidence: 99%

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A Coevolutionary Isomorphism Applied to Laboratory Studies of Competition

Pease

1985

Evolution

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Abstract.-Some empirical consequences of an isomorphism between the Lotka-Volterra competitive model and a coevolutionary competitive model are developed. In both the Lotka-Volterra and coevolutionary models, four competitive outcomes are possible: 1) species one wins, 2) species two wins, 3) indeterminate outcome, and 4) stable coexistence. These two models are isomorphic in the sense that the inequalities associated with a particularcompetitive outcome of the Lotka-Volterra model correspond in a one-to-one manner with similar inequalities associated with the same competitive outcome of the coevolutionary model. The inequalities of the Lotka-Voiterra model involve the competition coefficients themselves, while the inequalities of the coevolutionary model involve the genetic variances and covariances of the competition coefficients.The isomorphism suggests some alternative interpretations of the results of classical laboratory studies of competition. The Lotka-Volterra (or ecological) hypotheses postulate that the competition coefficients are constant and that genetic considerations play no role in determining the competitive outcome. By contrast, the evolutionary hypotheses derived from the coevolutionary model postulate that the competition coefficients are variables and that the genetic variances and covariances of the competition coefficients determine the competitive outcome. The isomorphism is applied to competitive exclusion and coexistence, and to competitive indeterminacy in Tribolium. In particular, the evolutionary hypotheses isomorphic to the two classical explanations of competitive indeterminacy, the demographic stochasticity and genetic founder effect hypotheses, are constructed.The theory developed here and in a previous paper (Pease, 1984) provides one perspective on the relation among the Lotka-Voiterra competition theory, quantitative genetics, competitive exclusion, the reversal of competitive dominance, coexistence, competitive indeterminacy in Tribolium, and experiments investigating the relation between genetic variability and the rate of evolution of fitness.Received May 21, 1984. Accepted October 24, 1984 In a recent paper, I showed that there exists an isomorphism between the competitive outcomes permitted by the Lotka-Volterra model (Gause, 1934;Lotka, 1932;Volterra, 1926) and the competitive outcomes permitted by a coevolutionary model (Pease, 1984). The competitive mechanisms implicit in the Lotka-Volterra model are ecological in character, and the model assumes that genetic considerations do not influence competitive outcomes. On the other hand, the genetic variances and covariances of the competition coefficients are important parameters in the coevolutionary model, hence its competitive mechanisms are evolutionary in character. In this paper, I will show how the evolutionary competitive mechanisms of the coevo1utionary model provide alternative explanations for some of the results of classical studies of competition and coexistence.The isomorphism was originally derived in connect...

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Section: Laboratory Studies Of Competitionsupporting

confidence: 53%

Section: Laboratory Studies Of Competitionmentioning

confidence: 79%

Section: Laboratory Studies Of Competitionmentioning

confidence: 99%

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A Coevolutionary Isomorphism Applied to Laboratory Studies of Competition

Pease

1985

Evolution

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“…To investigate it, they constructed a mathematical model with unrealistic assumptions. Some of the assumptions of this theoretical model were empirically false, but false models may still be useful (Levins, 1966(Levins, , 1968Wimsatt 2007): their broad conclusions may still be correct, and they may point to further experiments (e.g., Mertz, Cawthon, & Park, 1976). In all of this, Neyman, Park, and Scott were careful to make their assumptions clear, and to distinguish two kinds of work and of populationsdtheoretical and laboratory.…”

Section: Distinguishing Theoretical From Laboratory Populations In Thmentioning

confidence: 99%

The mind, the lab, and the field: Three kinds of populations in scientific practice

Winther

Giordano

Edge

et al. 2015

Studies in History and Philosophy of Science Part C: Studies in

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a b s t r a c tScientists use models to understand the natural world, and it is important not to conflate model and nature. As an illustration, we distinguish three different kinds of populations in studies of ecology and evolution: theoretical, laboratory, and natural populations, exemplified by the work of R. A. Fisher, Thomas Park, and David Lack, respectively. Biologists are rightly concerned with all three types of populations. We examine the interplay between these different kinds of populations, and their pertinent models, in three examples: the notion of "effective" population size, the work of Thomas Park on Tribolium populations, and model-based clustering algorithms such as Structure. Finally, we discuss ways to move safely between three distinct population types while avoiding confusing models and reality.Ó 2015 Elsevier Ltd. All rights reserved. When citing this paper, please use the full journal title Studies in History and Philosophy of Biological and Biomedical SciencesWhat are the relationships among the populations that biologists postulate in idealized theoretical models, the populations they set up in experimental laboratories, and the populations they survey and sample in the wild? We describe three qualitatively different kinds of populations at the heart of distinct styles of scientific practice in ecology and evolution, viz., theoretical, laboratory, and field investigations. Distinguishing three types of populationsdtheoretical, laboratory, and naturaldprovides a useful lens for viewing both past and contemporary work in ecology and evolutionary biology.Three examples illustrate the value of distinguishing theoretical, laboratory, and natural populations: the concept of "effective" population size, the work of Thomas Park on flour beetle populations, and the use of model-based genetic clustering algorithms such as Structure. In keeping with the "Genomics and Philosophy of Race" theme of the special issue in which this article appears, our trichotomy can assist analyses of the implications of genomic studies for claims about the existence (or the non-existence) of human races. In the conclusion, we suggest ways to avoid conflating the three kinds of populations. Researchers can cycle through natural, laboratory, and theoretical populations, expressing genuine interest in each population type. Theoretical, laboratory, and natural populations also pertain to fields beyond ecology and evolution, including statistics.We analyze scientific practice. Although questions regarding realism and anti-realism, the concepteworld relation, and the general ontology of science lurk, our trichotomy is not intended as a rubric for determining how much a model does or does not correspond to reality. Admittedly, an overarching aim of population biology is to understand the complex structure and dynamics of populations "in the wild." Even so, the multiple ontologies of scientific practice are complexdarguably there is a world in a theoretical model (e.g., Morgan, 2012) or in an experimental system (e.g., Leon...

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“…We designed this experiment to be a next logical step that builds on the long tradition of competition experiments using the Tribolium system (Park 1948(Park , 1954Park and Lloyd 1955;Mertz et al 1976;Lerner and Ho 1961;Lerner and Dempster 1962;Lerner 1962, 1966;Dawson 1970). Many of the concepts (such as competitive indeterminacy and demographic stochasticity) that have come out of these studies are now widely accepted.…”

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confidence: 99%

THE EFFECT OF COEXISTENCE ON COMPETITIVE OUTCOME IN TRIBOLIUM CASTANEUM AND TRIBOLIUM CONFUSUM

Goodnight

Craig²

1996

Evolution

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Abstract,-We describe an experiment exploring the effects of coexistence and population differentiation on the competitive outcome of two species of Tribolium flour beetles, T, castaneum and T, confusum. The only manipulation was whether the populations used in the competitive phase of the study were raised initially in mixed-species communities, single-species populations, or in the standard culture conditions used to maintain stocks in the laboratory, Any treatment effects observed were due to natural selection acting within populations and genetic drift. In the competitive phase, we examined 10 mixed-species communities and 10 pairs of single-species populations. We replicated each community 15 times to provide an assessment of the distribution of competitive outcome. Statistical analysis demonstrates the lineages within the treatments became highly differentiated for all measures of competitive outcome: the outcome of competition (which species won), time to extinction of one of the competing species, and census history. The fraction of the variance that is among lineages has been referred to as the group or community heritability. All of these measures of competitive outcome had high community level heritabilities indicating that competitive ability would evolve rapidly as a result of group or community level selection. In contrast, competitive outcome was not affected by whether the two species had coexisted prior to the competitive phase. This indicates that the outcome of competition was not systematically changed by processes acting within the two species communities.

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An experimental analysis of competitive indeterminacy in Tribolium.

Cited by 41 publications

References 17 publications

A Coevolutionary Isomorphism Applied to Laboratory Studies of Competition

A Coevolutionary Isomorphism Applied to Laboratory Studies of Competition

The mind, the lab, and the field: Three kinds of populations in scientific practice

THE EFFECT OF COEXISTENCE ON COMPETITIVE OUTCOME IN TRIBOLIUM CASTANEUM AND TRIBOLIUM CONFUSUM

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