LIFE ON A LEAF: CAUSES AND CONSEQUENCES OF OVIPOSITION-SITE CHOICE IN MANDUCA SEXTA

Persistent Link:
http://hdl.handle.net/10150/194365
Title:
LIFE ON A LEAF: CAUSES AND CONSEQUENCES OF OVIPOSITION-SITE CHOICE IN MANDUCA SEXTA
Author:
Potter, Kristen A.
Issue Date:
2010
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:
Phytophagous insects and plants comprise one half of all macroscopic organisms on Earth, and understanding plant-insect interactions has been a long-standing focus in ecological and evolutionary biology. A key challenge has been determining the factors that affect how insects distribute among plants. While ditrophic and tritrophic interactions are well known and enormously important, the biophysical context in which these interactions occur is largely unexplored. This dissertation examines how a plant's physical environment affects insect performance on, and preference for, its leaves.An insect's primary physiological challenges are staying within an appropriate temperature range and retaining sufficient water. These problems are exacerbated during the egg stage. Eggs have comparatively enormous ratios of surface area to volume, and their temperature is determined largely by where they are laid. Because they are small, eggs are nearly always immersed within their plant's boundary layer, a thin layer of still air that resists heat and moisture transfer between the plant and its surroundings. Almost no work has documented the microclimate to which insects are exposed in a plant's boundary layer, which likely differs substantially both from the ambient macroclimate, and from leaf to leaf.Because a female controls the location in which her eggs must develop, her choice of oviposition site may profoundly influence the success of her offspring. In this dissertation I examine how site-specific environmental variables, including microclimate, predation, and leaf nutrition, drive female oviposition preference and offspring performance in the hawkmoth, Manduca sexta L. (Lepidoptera: Sphingidae). I measure how leaves of M. sexta's primary host plants in the southwestern USA modify the temperature and humidity experienced by eggs, and how these leaf microclimates affect the performance of eggs and larvae. I then test whether this species' oviposition-site choices correlate with offspring performance with regard to microclimate, predation risk, and leaf nutrition. This dissertation is unique in focusing on the relatively unstudied biophysical context in which plant-insect interactions occur. Additionally, it is the first work that compares, together in a single study, the effects of varying multiple factors related to oviposition-site choice across all life history stages in a single model system.
Type:
text; Electronic Dissertation
Keywords:
Datura wrightii; humidity; insect eggs; microclimate; preference-performance hypothesis; temperature
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Ecology & Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Bronstein, Judith; Davidowitz, Goggy
Committee Chair:
Bronstein, Judith; Davidowitz, Goggy

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleLIFE ON A LEAF: CAUSES AND CONSEQUENCES OF OVIPOSITION-SITE CHOICE IN MANDUCA SEXTAen_US
dc.creatorPotter, Kristen A.en_US
dc.contributor.authorPotter, Kristen A.en_US
dc.date.issued2010en_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.abstractPhytophagous insects and plants comprise one half of all macroscopic organisms on Earth, and understanding plant-insect interactions has been a long-standing focus in ecological and evolutionary biology. A key challenge has been determining the factors that affect how insects distribute among plants. While ditrophic and tritrophic interactions are well known and enormously important, the biophysical context in which these interactions occur is largely unexplored. This dissertation examines how a plant's physical environment affects insect performance on, and preference for, its leaves.An insect's primary physiological challenges are staying within an appropriate temperature range and retaining sufficient water. These problems are exacerbated during the egg stage. Eggs have comparatively enormous ratios of surface area to volume, and their temperature is determined largely by where they are laid. Because they are small, eggs are nearly always immersed within their plant's boundary layer, a thin layer of still air that resists heat and moisture transfer between the plant and its surroundings. Almost no work has documented the microclimate to which insects are exposed in a plant's boundary layer, which likely differs substantially both from the ambient macroclimate, and from leaf to leaf.Because a female controls the location in which her eggs must develop, her choice of oviposition site may profoundly influence the success of her offspring. In this dissertation I examine how site-specific environmental variables, including microclimate, predation, and leaf nutrition, drive female oviposition preference and offspring performance in the hawkmoth, Manduca sexta L. (Lepidoptera: Sphingidae). I measure how leaves of M. sexta's primary host plants in the southwestern USA modify the temperature and humidity experienced by eggs, and how these leaf microclimates affect the performance of eggs and larvae. I then test whether this species' oviposition-site choices correlate with offspring performance with regard to microclimate, predation risk, and leaf nutrition. This dissertation is unique in focusing on the relatively unstudied biophysical context in which plant-insect interactions occur. Additionally, it is the first work that compares, together in a single study, the effects of varying multiple factors related to oviposition-site choice across all life history stages in a single model system.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectDatura wrightiien_US
dc.subjecthumidityen_US
dc.subjectinsect eggsen_US
dc.subjectmicroclimateen_US
dc.subjectpreference-performance hypothesisen_US
dc.subjecttemperatureen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEcology & Evolutionary Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorBronstein, Judithen_US
dc.contributor.advisorDavidowitz, Goggyen_US
dc.contributor.chairBronstein, Judithen_US
dc.contributor.chairDavidowitz, Goggyen_US
dc.contributor.committeememberHildebrand, John G.en_US
dc.contributor.committeememberPapaj, Daniel R.en_US
dc.identifier.proquest10930en_US
dc.identifier.oclc659754829en_US
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