Persistent Link:
http://hdl.handle.net/10150/289745
Title:
The ecology and evolution of tachinid-host associations
Author:
Stireman, John Oscar
Issue Date:
2001
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:
The Tachinidae is a taxonomically and ecologically diverse clade of parasitoids for which evolutionary and ecological relationships with hosts are largely unknown. Here, I employed a multidisciplinary approach to evaluate the determinants of patterns of host use in the Tachinidae. First, I examined spatio-temporal variation in the tachinid-dominated parasitoid assemblage of one lepidopteran species Grammia geneura . The parasitoid assemblage and parasitism rates varied dramatically among and within sampling sites, seasons, and years. I show that this variability may be a function of habitat-specific parasitism and indirect interactions between this host and other Macrolepidoptera through shared tachinid parasitoids. I then experimentally examined the host selection process in the tachinid Exorista mella. Host movement was an important elicitor of attack behavior. Flies also responded to odors associated with food plants of their host. Experienced flies attacked hosts more readily than did inexperienced flies. Based on these results, I proposed a host selection scenario for this tachinid species. E. mella also teamed to associate colors with hosts and avoided deterrent models that they had experienced. However, I failed to find evidence for odor learning. Learning of host-associated cues by E. mella may allow this parasitoid to take advantage of abundant host populations and maintain host-searching efficiency in an unpredictable environment. To examine how host-associated characteristics evolved in the Tachinidae, I reconstructed the evolutionary relationships within the subfamily Exoristinae using molecular data. Phylogenetic analyses generally supported recent classifications. Analyses of host-related characters indicated that tachinids show great evolutionary lability in behavior, morphology, and host range. Finally, I sampled host species to assess the determinants of tachinid community structure and host range. Several host characteristics were found to affect tachinid species richness. These patterns may be due to the opportunistic use of abundant hosts by polyphagous tachinids, enemy-free space provided by well-defended hosts, and the process of host location. Patterns of tachinid host use varied significantly with sample size, host diet breadth, host gregariousness, plant form, and host morphology. Taken together, these studies indicate high levels of plasticity in tachinid-host associations. This may be responsible for their ecological and evolutionary success.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology, Ecology.; Biology, Entomology.; Biology, Zoology.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Ecology and Evolutionary Biology
Degree Grantor:
University of Arizona
Advisor:
Moran, Nancy A.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleThe ecology and evolution of tachinid-host associationsen_US
dc.creatorStireman, John Oscaren_US
dc.contributor.authorStireman, John Oscaren_US
dc.date.issued2001en_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.abstractThe Tachinidae is a taxonomically and ecologically diverse clade of parasitoids for which evolutionary and ecological relationships with hosts are largely unknown. Here, I employed a multidisciplinary approach to evaluate the determinants of patterns of host use in the Tachinidae. First, I examined spatio-temporal variation in the tachinid-dominated parasitoid assemblage of one lepidopteran species Grammia geneura . The parasitoid assemblage and parasitism rates varied dramatically among and within sampling sites, seasons, and years. I show that this variability may be a function of habitat-specific parasitism and indirect interactions between this host and other Macrolepidoptera through shared tachinid parasitoids. I then experimentally examined the host selection process in the tachinid Exorista mella. Host movement was an important elicitor of attack behavior. Flies also responded to odors associated with food plants of their host. Experienced flies attacked hosts more readily than did inexperienced flies. Based on these results, I proposed a host selection scenario for this tachinid species. E. mella also teamed to associate colors with hosts and avoided deterrent models that they had experienced. However, I failed to find evidence for odor learning. Learning of host-associated cues by E. mella may allow this parasitoid to take advantage of abundant host populations and maintain host-searching efficiency in an unpredictable environment. To examine how host-associated characteristics evolved in the Tachinidae, I reconstructed the evolutionary relationships within the subfamily Exoristinae using molecular data. Phylogenetic analyses generally supported recent classifications. Analyses of host-related characters indicated that tachinids show great evolutionary lability in behavior, morphology, and host range. Finally, I sampled host species to assess the determinants of tachinid community structure and host range. Several host characteristics were found to affect tachinid species richness. These patterns may be due to the opportunistic use of abundant hosts by polyphagous tachinids, enemy-free space provided by well-defended hosts, and the process of host location. Patterns of tachinid host use varied significantly with sample size, host diet breadth, host gregariousness, plant form, and host morphology. Taken together, these studies indicate high levels of plasticity in tachinid-host associations. This may be responsible for their ecological and evolutionary success.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiology, Ecology.en_US
dc.subjectBiology, Entomology.en_US
dc.subjectBiology, Zoology.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineEcology and Evolutionary Biologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMoran, Nancy A.en_US
dc.identifier.proquest3010196en_US
dc.identifier.bibrecord.b41611226en_US
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