LIFE IN A FLY: THE ECOLOGY AND EVOLUTION OF THE OLIVE FLY ENDOSYMBIONT, CANDIDATUS ERWINIA DACICOLA.

Persistent Link:
http://hdl.handle.net/10150/195735
Title:
LIFE IN A FLY: THE ECOLOGY AND EVOLUTION OF THE OLIVE FLY ENDOSYMBIONT, CANDIDATUS ERWINIA DACICOLA.
Author:
Estes, Anne M.
Issue Date:
2009
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:
Bacterial endosymbionts of eukaryotes are generally studied in terms of their benefit or detriment to their hosts. The constraints that the host's life history imposes on its endosymbionts are rarely considered, although bacterial genome content and size are influenced by both the biotic and abiotic factors in the environment. The host organism is the primary habitat of the endosymbiont. Thus, desecribing the environment a host provides its endosymbiont is essential for understanding the evolution of endosymbiotic bacteria. I propose a system to classify the endosymbiotic environment by three characteristics: 1) host life cycle 2) host metabolism, and 3) endosymbiont location relative to host tissues. Insect-bacterial mutualisms have been classified in terms of endosymbiont environment. The majority of insect-bacterial mutualisms currently studied involve monophagous, hemimetabolous hosts that provide a relatively constant endosymbiotic enviroment. A relatively constant environment may explain the extremely reduced genomes of their endosymbionts. In contrast, polyphagous, holometabolous hosts provide the most variable endosymbiotic environment. In this work, I examined the interactions between the polyphagous, holometabolous insect, Bactrocera oleae (Rossi), and the enteric gammaproteobacterium, Candidatus Erwinia dacicola, throughout host development. Candidatus Erwinia dacicola was found in the digestive system of all life stages of wild olive flies. PCR and microscopy demonstrated that Ca. Erwinia dacicola resided intracellularly in the gastric caeca of the larval midgut, but extracellularly in the lumen of the foregut and ovipositor diverticulum of adult flies. I document the widespread distribution and high frequency of Ca. Er. dacicola in ten populations of wild olive flies sampled in four countries (3 Old World and 1 New World). The relative abundance of the bacterium was highest in adults and less prevalent in the egg and pupal stages. Among adult flies, the bacterium was most common in ovipositing females. These results suggest that Ca. Er. dacicola is a persistent, autochthonous endosymbiont of the olive fly. Finally, mating initiation was examined to study the influence of Ca. Er. dacicola on mating between a laboratory and a wild population of olive flies from Israel. Behavioral differences between the two populations, not presence of the endosymbiont, explained mating initiation.
Type:
text; Electronic Dissertation
Keywords:
endosymbiont; Erwinia; intracellular; microbial evolution; olive fly; symbiosis
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Ecology & Evolutionary Biology; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Bronstein, Judith L.; Pierson, Elizabeth A.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleLIFE IN A FLY: THE ECOLOGY AND EVOLUTION OF THE OLIVE FLY ENDOSYMBIONT, CANDIDATUS ERWINIA DACICOLA.en_US
dc.creatorEstes, Anne M.en_US
dc.contributor.authorEstes, Anne M.en_US
dc.date.issued2009en_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.abstractBacterial endosymbionts of eukaryotes are generally studied in terms of their benefit or detriment to their hosts. The constraints that the host's life history imposes on its endosymbionts are rarely considered, although bacterial genome content and size are influenced by both the biotic and abiotic factors in the environment. The host organism is the primary habitat of the endosymbiont. Thus, desecribing the environment a host provides its endosymbiont is essential for understanding the evolution of endosymbiotic bacteria. I propose a system to classify the endosymbiotic environment by three characteristics: 1) host life cycle 2) host metabolism, and 3) endosymbiont location relative to host tissues. Insect-bacterial mutualisms have been classified in terms of endosymbiont environment. The majority of insect-bacterial mutualisms currently studied involve monophagous, hemimetabolous hosts that provide a relatively constant endosymbiotic enviroment. A relatively constant environment may explain the extremely reduced genomes of their endosymbionts. In contrast, polyphagous, holometabolous hosts provide the most variable endosymbiotic environment. In this work, I examined the interactions between the polyphagous, holometabolous insect, Bactrocera oleae (Rossi), and the enteric gammaproteobacterium, Candidatus Erwinia dacicola, throughout host development. Candidatus Erwinia dacicola was found in the digestive system of all life stages of wild olive flies. PCR and microscopy demonstrated that Ca. Erwinia dacicola resided intracellularly in the gastric caeca of the larval midgut, but extracellularly in the lumen of the foregut and ovipositor diverticulum of adult flies. I document the widespread distribution and high frequency of Ca. Er. dacicola in ten populations of wild olive flies sampled in four countries (3 Old World and 1 New World). The relative abundance of the bacterium was highest in adults and less prevalent in the egg and pupal stages. Among adult flies, the bacterium was most common in ovipositing females. These results suggest that Ca. Er. dacicola is a persistent, autochthonous endosymbiont of the olive fly. Finally, mating initiation was examined to study the influence of Ca. Er. dacicola on mating between a laboratory and a wild population of olive flies from Israel. Behavioral differences between the two populations, not presence of the endosymbiont, explained mating initiation.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectendosymbionten_US
dc.subjectErwiniaen_US
dc.subjectintracellularen_US
dc.subjectmicrobial evolutionen_US
dc.subjectolive flyen_US
dc.subjectsymbiosisen_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.chairBronstein, Judith L.en_US
dc.contributor.chairPierson, Elizabeth A.en_US
dc.contributor.committeememberBronstein, Judith L.en_US
dc.contributor.committeememberPierson, Elizabeth A.en_US
dc.contributor.committeememberPapaj, Daniel R.en_US
dc.contributor.committeememberPierson, Leland S.en_US
dc.contributor.committeememberArnold, Anne Elizabethen_US
dc.identifier.proquest10797en_US
dc.identifier.oclc659753650en_US
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