Persistent Link:
http://hdl.handle.net/10150/184543
Title:
Host use and foraging in the parasitic plant Cuscuta subinclusa.
Author:
Kelly, Colleen Kay.
Issue Date:
1988
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:
Foraging theory predicts active responses by organisms upon encounter with a resource, as opposed to the passive responses of differential survivorship and growth. Stems of the parasitic plant Cuscuta subinclusa invest in resource acquisition (coil) relative to host quality in a way predicted by the marginal value theorem (MVT) in that: (1) stem coiling, the necessary antecedent and determinant of resource uptake, precedes exploitation of host materials; and (2) mean coiling on a host species is proportional to: (a) mean growth/haustorium, (b) mean biomass accumulation over the season, and (c) mean parasite growth/host individual. Coiling is correlated with growth/host individual for the 5 native host species examined, but not when a non-native species is added to the model, suggesting coiling response is a result of natural selection. Preliminary evidence indicates that coiling in C. subinclusa is induced by host bark chemicals. Resource-poor stems of C. subinclusa are more likely to coil, and coil more, than resource-rich stems, thus nutritional state of the parasite as well as host value affects foraging responses. Evidence from other experiments suggests that the costs of growth, or "search costs", may affect host acceptability. When water is readily available, transplanted C. subinclusa stems are less likely to coil on branches of Platanus racemosa. During the dry season, when cellular expansion is difficult, all p. racemosa branches were coiled upon. Large parasites are more likely to over-winter and set seed a second season, and parasites that start from over-wintered tissue are significantly larger at flowering than are those that have started from seed. Seed set is correlated with parasite size, thus linking foraging response and fitness of the plant. C. subinclusa's foraging response does not, however, predict population level patterns of host use. The principal determinant of host use by C. subinclusa is average proximity of a species to Malosma laurina. Parasite individuals infest many host species each season, but initially establish, set most seed, and over-winter only on M. laurina. Individual response of C. subinclusa contributes to the model of host use only after proximity to M. laurina is accounted for, suggesting that mechanisms maximizing exploitation of a host take effect after contact between host and parasite.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dodder.; Parasitic plants.; Host-parasite relationships.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Ecology and Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Venable, D. Lawrence

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHost use and foraging in the parasitic plant Cuscuta subinclusa.en_US
dc.creatorKelly, Colleen Kay.en_US
dc.contributor.authorKelly, Colleen Kay.en_US
dc.date.issued1988en_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.abstractForaging theory predicts active responses by organisms upon encounter with a resource, as opposed to the passive responses of differential survivorship and growth. Stems of the parasitic plant Cuscuta subinclusa invest in resource acquisition (coil) relative to host quality in a way predicted by the marginal value theorem (MVT) in that: (1) stem coiling, the necessary antecedent and determinant of resource uptake, precedes exploitation of host materials; and (2) mean coiling on a host species is proportional to: (a) mean growth/haustorium, (b) mean biomass accumulation over the season, and (c) mean parasite growth/host individual. Coiling is correlated with growth/host individual for the 5 native host species examined, but not when a non-native species is added to the model, suggesting coiling response is a result of natural selection. Preliminary evidence indicates that coiling in C. subinclusa is induced by host bark chemicals. Resource-poor stems of C. subinclusa are more likely to coil, and coil more, than resource-rich stems, thus nutritional state of the parasite as well as host value affects foraging responses. Evidence from other experiments suggests that the costs of growth, or "search costs", may affect host acceptability. When water is readily available, transplanted C. subinclusa stems are less likely to coil on branches of Platanus racemosa. During the dry season, when cellular expansion is difficult, all p. racemosa branches were coiled upon. Large parasites are more likely to over-winter and set seed a second season, and parasites that start from over-wintered tissue are significantly larger at flowering than are those that have started from seed. Seed set is correlated with parasite size, thus linking foraging response and fitness of the plant. C. subinclusa's foraging response does not, however, predict population level patterns of host use. The principal determinant of host use by C. subinclusa is average proximity of a species to Malosma laurina. Parasite individuals infest many host species each season, but initially establish, set most seed, and over-winter only on M. laurina. Individual response of C. subinclusa contributes to the model of host use only after proximity to M. laurina is accounted for, suggesting that mechanisms maximizing exploitation of a host take effect after contact between host and parasite.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDodder.en_US
dc.subjectParasitic plants.en_US
dc.subjectHost-parasite relationships.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEcology and Evolutionary Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorVenable, D. Lawrenceen_US
dc.contributor.committeememberRosenzweig, Michael L.en_US
dc.contributor.committeememberStrauss, Richard E.en_US
dc.contributor.committeememberBrown, James H.en_US
dc.contributor.committeememberTelewski, Frank W.en_US
dc.identifier.proquest8905795en_US
dc.identifier.oclc701901450en_US
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