COMPETITION, PREDATION AND THE MAINTENANCE OF DIMORPHISM IN AN ACORN BARNACLE (CHTHAMALUS ANISOPOMA) POPULATION.

Persistent Link:
http://hdl.handle.net/10150/187727
Title:
COMPETITION, PREDATION AND THE MAINTENANCE OF DIMORPHISM IN AN ACORN BARNACLE (CHTHAMALUS ANISOPOMA) POPULATION.
Author:
LIVELY, CURTIS MICHAEL.
Issue Date:
1984
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The purpose of this study was to determine how two morphs of the acorn barnacle, Chthamalus anisopoma, coexist on rocky intertidal shores in the northern Gulf of California. The test of one of these forms (here called "typical") has the conical, volcano shape which is characteristic of acorn barnacles while the test of the atypical form (here called "bent") grows bent-over so that the plane of the aperture's rim is perpendicular to the substrate. I tested the hypotheses that bents are more resistant than typicals to: (1) desiccation during low tides and (2) attack by a carnivorous snail (Acanthina angelica) involving the use of a labial spine. These two hypotheses (which were suggested from analysis of the distribution patterns of the two morphs) were tested in conjunction with experiments designed to determine whether the bent form is genetically controlled or environmentally induced. The results indicated that the bent-over morph is a developmental response to the presence of A. angelica and that it is more resistant than the typical form to specialized predation by this gastropod. I also tested the hypotheses that: (1) bents are inferior competitors for primary rock space, and (2) the bent-over morphology places constraints on growth and reproduction. I found no evidence to suggest that bents are inferior competitors for space. They were, however, found to grow more slowly than typicals and to brood fewer eggs per unit body size. In summary, the bent-over form of C. anisopoma is a conditional response to the presence of a predator and both the conditional strategy and the dimorphism appear to be maintained by a trade-off between resistance to predation and the ability to convert resources into offspring.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Barnacles -- Mexico -- California, Gulf of.; Acorn barnacle.; Dimorphism (Animals)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Ecology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Hendrickson, J. R.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleCOMPETITION, PREDATION AND THE MAINTENANCE OF DIMORPHISM IN AN ACORN BARNACLE (CHTHAMALUS ANISOPOMA) POPULATION.en_US
dc.creatorLIVELY, CURTIS MICHAEL.en_US
dc.contributor.authorLIVELY, CURTIS MICHAEL.en_US
dc.date.issued1984en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe purpose of this study was to determine how two morphs of the acorn barnacle, Chthamalus anisopoma, coexist on rocky intertidal shores in the northern Gulf of California. The test of one of these forms (here called "typical") has the conical, volcano shape which is characteristic of acorn barnacles while the test of the atypical form (here called "bent") grows bent-over so that the plane of the aperture's rim is perpendicular to the substrate. I tested the hypotheses that bents are more resistant than typicals to: (1) desiccation during low tides and (2) attack by a carnivorous snail (Acanthina angelica) involving the use of a labial spine. These two hypotheses (which were suggested from analysis of the distribution patterns of the two morphs) were tested in conjunction with experiments designed to determine whether the bent form is genetically controlled or environmentally induced. The results indicated that the bent-over morph is a developmental response to the presence of A. angelica and that it is more resistant than the typical form to specialized predation by this gastropod. I also tested the hypotheses that: (1) bents are inferior competitors for primary rock space, and (2) the bent-over morphology places constraints on growth and reproduction. I found no evidence to suggest that bents are inferior competitors for space. They were, however, found to grow more slowly than typicals and to brood fewer eggs per unit body size. In summary, the bent-over form of C. anisopoma is a conditional response to the presence of a predator and both the conditional strategy and the dimorphism appear to be maintained by a trade-off between resistance to predation and the ability to convert resources into offspring.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBarnacles -- Mexico -- California, Gulf of.en_US
dc.subjectAcorn barnacle.en_US
dc.subjectDimorphism (Animals)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEcologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHendrickson, J. R.en_US
dc.contributor.committeememberBrown, James H.en_US
dc.contributor.committeememberKodric-Brown, Astriden_US
dc.contributor.committeememberThomson, D. A.en_US
dc.contributor.committeememberVleck, Daviden_US
dc.identifier.proquest8421974en_US
dc.identifier.oclc691293925en_US
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