Trophic polymorphism and behavioral differences decrease intraspecific competition in a cichlid, Herichthys minckleyi

Brook O. Swanson, Alice C Gibb, Jane C Marks, Dean A. Hendrickson

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

Resource polymorphisms, or morphological variations related to resource use, are common in fishes and are thought to be a possible step in speciation. This study experimentally tests the hypothesis that fitness (as estimated by growth rates) is increased by the presence of multiple trophic morphotypes (or morphs) within a population. Cage experiments were used to quantify the intraspecific competitive interactions between morphs of the polymorphic cichlid Herichthys minckleyi in Cuatro Ciénegas, Mexico. Results suggest that competition is reduced between morphs in mixed-morph treatments relative to equal-density single-morph treatments. Field studies revealed that the morphs feed in different microhabitats and use different feeding behaviors within these microhabitats. These results suggest that the polymorphism is maintained in the population because it decreases competition between the morphs, and that differences in feeding behavior facilitate resource partitioning.

Original languageEnglish (US)
Pages (from-to)1441-1446
Number of pages6
JournalEcology
Volume84
Issue number6
StatePublished - Jun 2003

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cichlid
intraspecific competition
feeding behavior
morphs
microhabitat
polymorphism
niche partitioning
morphotype
resource use
fitness
microhabitats
resource
fish
experiment
cages
Mexico
Herichthys
testing
field study
test

Keywords

  • Cichlid
  • Competition
  • Ecological speciation
  • Feeding behavior
  • Herichthys minckleyi
  • Intraspecific variation
  • Polymorphism
  • Resource partitioning

ASJC Scopus subject areas

  • Ecology

Cite this

Trophic polymorphism and behavioral differences decrease intraspecific competition in a cichlid, Herichthys minckleyi. / Swanson, Brook O.; Gibb, Alice C; Marks, Jane C; Hendrickson, Dean A.

In: Ecology, Vol. 84, No. 6, 06.2003, p. 1441-1446.

Research output: Contribution to journalArticle

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AU - Marks, Jane C

AU - Hendrickson, Dean A.

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