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

Swanson, Brook O. and Gibb, Alice C. and Marks, Jane C. and Hendrickson, Dean A. (2003) Trophic polymorphism and behavioral differences decrease intraspecific competition in a cichlid, Herichthys minckleyi. Ecology, 84 (6). pp. 1441-1446. ISSN 0012-9658


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Publisher’s or external URL: http://dx.doi.org/10.1890/02-0353


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 Cienegas, 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.

Item Type: Article
Publisher’s Statement: Copyright 2004 by the Ecological Society of America.
ID number or DOI: 10.1890/02-0353
Keywords: brook charr; cichlid; Cichlids; Communities; Competition; coral-reef fish; displacement; ecological speciation; feeding behavior; Herichthys minckleyi; intraspecific variation; mechanisms; natural-selection; Polymorphism; Population; Resource partitioning; resource partitioning; resource polymorphisms; Specialization; sunfish lepomis-gibbosus
Subjects: Q Science > QL Zoology
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > Biological Sciences
Date Deposited: 12 Oct 2015 22:39
URI: http://openknowledge.nau.edu/id/eprint/1392

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