Temporal and spatial scales in foraging ecology: Testing hypotheses with spiders and squirrels.

Persistent Link:
http://hdl.handle.net/10150/186070
Title:
Temporal and spatial scales in foraging ecology: Testing hypotheses with spiders and squirrels.
Author:
Smallwood, Peter Diehl.
Issue Date:
1992
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:
Animal foraging behavior is shaped by patterns and processes that operate on several temporal and spatial scales. In chapter 1, I briefly review the meaning and importance of temporal and spatial scales. In chapter 2, I examine the foraging behavior of the Long Jawed spider (Tetragnatha elongata). In North Carolina, the spider exhibits the counter intuitive behavior of relocating its web daily in rich habitats, but rebuilding its web on the same site for many days in a row in poor habitats. I test a risk-sensitive foraging model of this behavior, but its predictions were not met. I develop an alternative hypothesis to explain the behavior of Long Jawed spiders: that the higher density of spiders in rich habitats results in more frequent interactions between spiders, and that these interactions provoke spiders to relocate more often in rich habitats. I report the results of density-reduction experiments, which corroborate my hypothesis. In chapter 3, I examine the foraging and storing strategy of the Eastern Gray Squirrel (Sciurus carolinensis). The squirrels ate most of the white oak (WO) acorns, and buried most of the red oak (RO) acorns, confirming my prediction. I also present the results of an experiment designed to reveal whether squirrels used tannin and/or fat content of acorns to distinguish between acorns of different species. The results of this experiment were inconclusive. In another experiment, I buried a large number of acorns, and assessed samples of acorns retrieved at intervals through the fall/winter season. I found that tannin levels in RO acorns did not decline during their interment, rendering an alternative hypothesis untenable. Further, I confirmed an earlier assumption: stored WO acorns do suffer more insect damage than RO acorns. I hypothesize that the storing and foraging strategy of squirrels may affect the distribution of oaks, and review evidence from the literature that supports this hypothesis. Finally, I argue that Clark's Nutcracker (Columbiana nucifraga) may employ the same strategy as it forages for pine seeds, and again review evidence from the literature to support this hypothesis. (Abstract shortened by UMI.)
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Animals -- Food.; Tetragnatha -- Food.; Gray squirrel -- Food.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Ecology and Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Rosenzweig, Michael L.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleTemporal and spatial scales in foraging ecology: Testing hypotheses with spiders and squirrels.en_US
dc.creatorSmallwood, Peter Diehl.en_US
dc.contributor.authorSmallwood, Peter Diehl.en_US
dc.date.issued1992en_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.abstractAnimal foraging behavior is shaped by patterns and processes that operate on several temporal and spatial scales. In chapter 1, I briefly review the meaning and importance of temporal and spatial scales. In chapter 2, I examine the foraging behavior of the Long Jawed spider (Tetragnatha elongata). In North Carolina, the spider exhibits the counter intuitive behavior of relocating its web daily in rich habitats, but rebuilding its web on the same site for many days in a row in poor habitats. I test a risk-sensitive foraging model of this behavior, but its predictions were not met. I develop an alternative hypothesis to explain the behavior of Long Jawed spiders: that the higher density of spiders in rich habitats results in more frequent interactions between spiders, and that these interactions provoke spiders to relocate more often in rich habitats. I report the results of density-reduction experiments, which corroborate my hypothesis. In chapter 3, I examine the foraging and storing strategy of the Eastern Gray Squirrel (Sciurus carolinensis). The squirrels ate most of the white oak (WO) acorns, and buried most of the red oak (RO) acorns, confirming my prediction. I also present the results of an experiment designed to reveal whether squirrels used tannin and/or fat content of acorns to distinguish between acorns of different species. The results of this experiment were inconclusive. In another experiment, I buried a large number of acorns, and assessed samples of acorns retrieved at intervals through the fall/winter season. I found that tannin levels in RO acorns did not decline during their interment, rendering an alternative hypothesis untenable. Further, I confirmed an earlier assumption: stored WO acorns do suffer more insect damage than RO acorns. I hypothesize that the storing and foraging strategy of squirrels may affect the distribution of oaks, and review evidence from the literature that supports this hypothesis. Finally, I argue that Clark's Nutcracker (Columbiana nucifraga) may employ the same strategy as it forages for pine seeds, and again review evidence from the literature to support this hypothesis. (Abstract shortened by UMI.)en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAnimals -- Food.en_US
dc.subjectTetragnatha -- Food.en_US
dc.subjectGray squirrel -- Food.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.chairRosenzweig, Michael L.en_US
dc.contributor.committeememberBronstein, Judith L.en_US
dc.contributor.committeememberRussell, Stephen M.en_US
dc.contributor.committeememberVenable, D. Lawrenceen_US
dc.contributor.committeememberVleck, David J.en_US
dc.identifier.proquest9309031en_US
dc.identifier.oclc702403761en_US
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