Date of Graduation

12-2015

Document Type

Thesis

Degree Name

Master of Science in Entomology (MS)

Degree Level

Graduate

Department

Entomology

Advisor/Mentor

Frederick M. Stephen

Committee Member

David Hensley

Second Committee Member

Timothy Kring

Keywords

Biological sciences, Ips grandicollis, Monochamus, Shortleaf pine

Abstract

Insects in the genus Monochamus are medium to large-sized, wood-boring beetles whose primary hosts in the Northern Hemisphere are pine trees. These beetles interact with both conifer hosts and associated insects throughout their life history. Past research has demonstrated that Monochamus are saprophagic, but recent findings show that they may colonize healthy pine trees. To determine if southeastern Monochamus could colonize healthy pines, adult Monochamus were attracted to healthy shortleaf pine trees from May to September, 2014, using host volatiles, Ips bark beetle kairomones, and congeneric pheromones. Subsequent development of oviposited eggs from 18 host trees was monitored. The results demonstrate that southeastern Monochamus species may oviposit into healthy shortleaf pines, but host resin flow inhibits egg survival and larval development.

Southeastern Monochamus are also associated with the southern pine beetle feeding guild, which includes three species of Ips bark beetles that inhabit pine hosts. Species of Monochamus and Ips share host trees and many aspects of their life history making sub-cortical interaction highly likely. In Arkansas M. titillator and I. grandicollis are the most abundant of each genera. When hosts are shared I. grandicollis first colonize hosts while M. titillator land and colonize some days afterwards. To determine if sub-cortical interactions between both species occur and lead to decreased survival and emergence of I. grandicollis, shortleaf pine bolts were exposed to both beetles under controlled laboratory conditions and I. grandicollis emergence was monitored. Both number of M. titillator females introduced and the time between I. grandicollis and M. titillator colonization was varied. My results demonstrate that sub-cortical interaction between M. titillator and I. grandicollis does occur and that I. grandicollis survival and emergence is reduced by their interactions. Results also show that these interactions do not depend on the difference in colonization time between the two species, at least within the first six days after I. grandicollis have started colonization.

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