Size bimodality in monospecific populations: a critical review of potential mechanisms.

M. A. Huston, D. L. Deangelis

Research output: Contribution to journalArticlepeer-review

115 Scopus citations


Changes in size distributions, including changes that produce bimodality, result from the interaction of several characteristics of the individuals composing the population with factors that influence those characteristics. The critical factors can be classified as 1) initial distribution of individual sizes; 2) distribution of growth rates among individuals; 3) size and time dependence of the growth rate of each individual; and 4) mortality that may affect each size class differently. Each factor may be influenced by an individual's genetic makeup, and by abiotic and biotic environmental effects. The biological mechanisms that may affect these factors are classified as either 'inherent' (genetic) or 'imposed' and as either 'noninteractive' or 'interactive', depending on whether they require interactions among the individual organisms in order to be expressed. Examples are reviewed from the population biology of fish and terrestrial plants. The class of imposed, interactive mechanisms, which includes competition, provides many examples of bimodality that are most interesting ecologically, but these mechanisms are probably the least likely to produce the bimodalities found in nature. Imposed, noninteractive mechanisms resulting from the effect of temporal and spatial heterogeneity on all 4 of the factors influencing size distributions are far more likely than interactive mechanisms to explain size bimodalities in nature. -from Authors

Original languageEnglish (US)
Pages (from-to)678-707
Number of pages30
JournalAmerican Naturalist
Issue number5
StatePublished - Jan 1 1987

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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