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dc.contributor.advisorChairperson, Graduate Committee: David K. Weaveren
dc.contributor.authorDavis, Rex Addisonen
dc.coverage.spatialMontanaen
dc.date.accessioned2014-07-14T16:05:10Z
dc.date.available2014-07-14T16:05:10Z
dc.date.issued2013en
dc.identifier.urihttps://scholarworks.montana.edu/xmlui/handle/1/3477en
dc.description.abstractCephus cinctus Norton, the wheat stem sawfly, is Montana's most damaging wheat pest. The species is responsible for large yield reductions across the northern Great Plains, costing hundreds of millions of dollars every year. Two congeneric braconid parasitoid species, Bracon cephi Gahan and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae), are found simultaneously in Montana wheat fields, are active at the same time of year and both use C. cinctusas a host. Their role as biological control agents of C. cinctusis currently being explored. It is unknown how these morphologically similar parasitoid species maintain reproductive isolation. This study explored several mechanisms allowing B. cephiand B. lissogaster to remain reproductively isolated and exposed new areas of study and questions of interest regarding the reproductive isolation of these species. No differences in reproductive timing were observed using field-based population abundance surveys, suggesting that alternative isolation mechanisms are being used. A group of candidate sex pheromones analyzed for presence, absence, and relative concentration in each of the parasitoid species' Dufour's glands indicated substantial differences between the two species. These differences suggest a possible role for the Dufour's gland in maintaining reproductive isolation. However, these candidate sex pheromones did not produce significantly different electrophysiological responses in B. cephiand B. lissogaster. Although this suggests that these candidate sex pheromones may not play a role, mating trials and behavioral assays conducted to assess the interactions between sex and species indicated that the species maintain reproductive isolation in laboratory settings.en
dc.language.isoenen
dc.publisherMontana State University - Bozeman, College of Agricultureen
dc.subject.lcshParasitesen
dc.subject.lcshWaspsen
dc.subject.lcshCephus cinctusen
dc.subject.lcshAgricultural pestsen
dc.subject.lcshPests--Biological controlen
dc.subject.lcshReproductionen
dc.subject.lcshSpeciesen
dc.subject.lcshEvolutionen
dc.titleMechanisms for reproductive isolation in two congeneric parasitoids of the wheat stem sawflyen
dc.typeThesisen
dc.rights.holderCopyright 2013 by Rex Addison Davisen
thesis.catalog.ckey2538936en
thesis.degree.committeemembersMembers, Graduate Committee: Robert K. D. Peterson; Kevin O'Neill; Jack Martin.en
thesis.degree.departmentLand Resources & Environmental Sciences.en
thesis.degree.genreThesisen
thesis.degree.nameMSen
thesis.format.extentfirstpage1en
thesis.format.extentlastpage83en
mus.relation.departmentLand Resources & Environmental Sciences.en_US


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