Regulation of phosphorus stoichiometry and growth rate of consumers: Theoretical and experimental analyses with Daphnia

Yuichiro Shimizu, Jotaro Urabe

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Initial theories of ecological stoichiometry were based on the assumption that the mass-specific content of key nutrient elements (such as P), changes little within a consumer species. However, evidence has shown that this content changes substantially according to feeding conditions. To clarify how the specific P content (S P) of a consumer species depends on food conditions and relates to the growth rate, we constructed a multiple mass-balance model incorporating feeding and metabolic costs and stoichiometrically regulated releases for C and P. The validity of the model was then tested experimentally by examining the growth rates and S P of Daphnia pulicaria under various food conditions. The experimental observation agreed qualitatively well with the model, showing that the S P of consumers relates positively to growth rate at high food C:P ratios but negatively at low food C:P ratios. Thus, within a consumer species, individuals with high S P do not necessarily grow at high rates. The concordance in results between the model and our observation suggests that maintenance costs for both P and C are substantial regardless of food conditions and play crucial roles in determining the relationship between the S P and growth rate of consumers.

Original languageEnglish
Pages (from-to)21-31
Number of pages11
JournalOecologia
Volume155
Issue number1
DOIs
Publication statusPublished - 2008 Feb 1

Keywords

  • Assimilation efficiency
  • Carbon:phosphorus ratio
  • Growth rate hypothesis
  • Maintenance costs
  • Mass balance model

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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