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Evaluation of hybridization among three Laricobius species, predators of hemlock woolly adelgid, (Adelgidae)

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dc.contributor.authorFischer, Melissa J.en
dc.contributor.committeechairKok, Loke T.en
dc.contributor.committeechairSalom, Scott M.en
dc.contributor.committeememberBrewster, Carlyle C.en
dc.contributor.committeememberOpell, Brent D.en
dc.contributor.committeememberHavill, Nathan P.en
dc.contributor.departmentEntomologyen
dc.date.accessioned2015-03-27T06:00:11Zen
dc.date.available2015-03-27T06:00:11Zen
dc.date.issued2013-10-02en
dc.description.abstractHybridization was evaluated among three Laricobius spp. involved in the biological control of hemlock woolly adelgid (Adelges tsugae Annand). Following lab mating studies, there was no evidence that Laricobius osakensis Montgomery and Yu could produce hybrid progeny with either Laricobius nigrinus Fender or Laricobius rubidus LeConte. Interaction between L. osakensis and L. nigrinus did not result in a lower production of progeny as a result of fitness costs associated with interspecific mating attempts. Laricobius nigrinus and L. rubidus hybrids were produced in the lab and collected in the field. Hybrid progeny showed very little evidence of decreased fitness. For example, there was no significant difference in the number of days it took for hybrids and pure parental species to develop from egg hatch to the prepupal stage, there was no difference among hybrids and pure parental species in the head capsule widths and larval lengths for the first through third instar, and there was evidence of an F2 generation from field collected specimens. Hybrids produced in the lab had intermediate shaped genital paramere angles compared with parental species, and had elytra coloration similar to that of L. rubidus. Hybrids showed no host preference in the lab, but a preference for Adelges tsugae in the field. Of 12 site factors examined, only the number of years that L. nigrinus was present at the site was found to be associated with percent hybrids. Contamination of the L. osakensis colony with Laricobius naganoensis Leschen resulted in the need to develop molecular methods to differentiate L. osakensis from L. naganoensis. Three restriction enzymes were found that correctly differentiated the two species.en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:1623en
dc.identifier.urihttp://hdl.handle.net/10919/51649en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectLaricobius nigrinusen
dc.subjectLaricobius rubidusen
dc.subjectLaricobius osakensisen
dc.subjectLaricobius naganoensisen
dc.subjectbiological controlen
dc.subjecthemlock woolly adelgiden
dc.subjectpine bark adelgiden
dc.subjecthybridizationen
dc.titleEvaluation of hybridization among three Laricobius species, predators of hemlock woolly adelgid, (Adelgidae)en
dc.typeDissertationen
thesis.degree.disciplineEntomologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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