Heritable Microbial Endosymbionts in Insects: Insights from the Study of a Parasitic Wasp and its Cockroach Host

Persistent Link:
http://hdl.handle.net/10150/195875
Title:
Heritable Microbial Endosymbionts in Insects: Insights from the Study of a Parasitic Wasp and its Cockroach Host
Author:
Gibson, Cara
Issue Date:
2008
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:
Endosymbiosis is a pervasive phenomenon that has been a powerful force in insect evolution. In many well studied insect-bacterial associations, the bacteria can serve as reproductive manipulators, nutritional mutualists or defenders of their hosts. Fungi are also frequently associated with insects, and initial estimates suggest that these fungi are hyperdiverse. Saving a handful of examples, however, the functions of these fungi within insect hosts are largely unknown. This dissertation begins with a review that lays the conceptual groundwork for understanding bacterial and fungal endosymbiosis in insects. I make predictions about why one versus the other microbe might serve the insect, given any unique physiological, ecological or evolutionary conditions. I then aim to derive insights about microbial symbiosis by focusing on a particular system, that of brownbanded cockroaches, Supella longipalpa (Blattaria: Blattellidae) and their specialist wasp parasitoids, Comperia merceti (Hymenoptera: Encyrtidae). Here, I identify the symbiotic community of these two insects by using both culture-dependent and independent methods to characterize the vertically transmitted bacterial and fungal associates. Finally, I show that a heritable fungus in C. merceti, long presumed to be a mutualist, is parasitic under laboratory conditions: infected wasps incur fitness costs for housing the fungal symbiont relative to uninfected wasps. Additionally, although the fungus is not horizontally transmitted sexually, it is readily horizontally transmitted from the offspring of infected females to those of uninfected females that are using the same host.
Type:
text; Electronic Dissertation
Keywords:
bacterial symbionts; cockroach host-parasitoid wasp; insect-fungal symbiosis; microbial consortia; symbiont transmission dynamics; yeast symbionts
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Entomology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Hunter, Molly
Committee Chair:
Hunter, Martha S.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleHeritable Microbial Endosymbionts in Insects: Insights from the Study of a Parasitic Wasp and its Cockroach Hosten_US
dc.creatorGibson, Caraen_US
dc.contributor.authorGibson, Caraen_US
dc.date.issued2008en_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.abstractEndosymbiosis is a pervasive phenomenon that has been a powerful force in insect evolution. In many well studied insect-bacterial associations, the bacteria can serve as reproductive manipulators, nutritional mutualists or defenders of their hosts. Fungi are also frequently associated with insects, and initial estimates suggest that these fungi are hyperdiverse. Saving a handful of examples, however, the functions of these fungi within insect hosts are largely unknown. This dissertation begins with a review that lays the conceptual groundwork for understanding bacterial and fungal endosymbiosis in insects. I make predictions about why one versus the other microbe might serve the insect, given any unique physiological, ecological or evolutionary conditions. I then aim to derive insights about microbial symbiosis by focusing on a particular system, that of brownbanded cockroaches, Supella longipalpa (Blattaria: Blattellidae) and their specialist wasp parasitoids, Comperia merceti (Hymenoptera: Encyrtidae). Here, I identify the symbiotic community of these two insects by using both culture-dependent and independent methods to characterize the vertically transmitted bacterial and fungal associates. Finally, I show that a heritable fungus in C. merceti, long presumed to be a mutualist, is parasitic under laboratory conditions: infected wasps incur fitness costs for housing the fungal symbiont relative to uninfected wasps. Additionally, although the fungus is not horizontally transmitted sexually, it is readily horizontally transmitted from the offspring of infected females to those of uninfected females that are using the same host.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectbacterial symbiontsen_US
dc.subjectcockroach host-parasitoid waspen_US
dc.subjectinsect-fungal symbiosisen_US
dc.subjectmicrobial consortiaen_US
dc.subjectsymbiont transmission dynamicsen_US
dc.subjectyeast symbiontsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineEntomologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHunter, Mollyen_US
dc.contributor.chairHunter, Martha S.en_US
dc.contributor.committeememberHunter, Martha S.en_US
dc.contributor.committeememberArnold, Anne Elizabethen_US
dc.contributor.committeememberCarrière, Yvesen_US
dc.contributor.committeememberMaddison, Daviden_US
dc.contributor.committeememberMoran, Nancyen_US
dc.identifier.proquest10123en_US
dc.identifier.oclc659750664en_US
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