The light at the end of the tunnel: photosensitivity in developing mountain pine beetle (Dendroctonus ponderosae)

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dc.contributor.authorWertman, Debra
dc.contributor.supervisorPerlman, Steven John
dc.date.accessioned2017-12-11T19:47:07Z
dc.date.copyright2017en_US
dc.date.issued2017-12-11
dc.degree.departmentDepartment of Biologyen_US
dc.degree.levelMaster of Science M.Sc.en_US
dc.description.abstractThis research explores the capacity for functional photoreception in larvae of the mountain pine beetle (Dendroctonus ponderosae), an extremely important forest pest insect that is well adapted for development beneath the bark of pine trees. Phototaxis tests, gene expression analysis and development experiments were integrated to assess mountain pine beetle larvae for light sensitivity. When presented with a phototaxis choice test, larvae preferred dark over light microhabitats, revealing that larvae sense and respond behaviourally to light. Long wavelength opsin transcription was identified in all life stages, including eggs and larvae, suggesting that D. ponderosae possesses extraretinal photosensitive capabilities across its life cycle. The long wavelength opsin could function in phototaxis or the development phenology of immature beetles, while the ultraviolet opsin, only found to be expressed in pupae and adults, is likely to function in dispersal via the compound eyes. Results from two development experiments reveal an effect of photoperiod treatment on beetle development rate when reared from the egg stage, but not when reared from mature larvae, indicating that a critical photosensitive life stage(s) must occur in D. ponderosae prior to the third larval instar. An effect of photoperiod on adult emergence rates, however, appears to be independent of larval rearing conditions. The discovery of opsin expression and negative phototaxis in eyeless mountain pine beetle larvae, in addition to an effect of photoperiod on immature development and adult emergence rates, suggest that light and photoperiodism likely function in survival and life cycle coordination in this species.en_US
dc.description.embargo2018-10-17
dc.description.scholarlevelGraduateen_US
dc.identifier.urihttp://hdl.handle.net/1828/8853
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.subjectmountain pine beetleen_US
dc.subjectphotosensitivityen_US
dc.subjectextraretinal photoreceptionen_US
dc.subjectphototaxisen_US
dc.subjectphotoperiodismen_US
dc.subjectcircadian regulationen_US
dc.subjectlow-light habitaten_US
dc.subjectdevelopment rateen_US
dc.subjectemergence rateen_US
dc.subjectbeetle opsinsen_US
dc.subjecteyeless larvaeen_US
dc.subjectcritical photosensitive life stageen_US
dc.titleThe light at the end of the tunnel: photosensitivity in developing mountain pine beetle (Dendroctonus ponderosae)en_US
dc.typeThesisen_US

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