Introduced species have the potential to cause great environmental damage, but many
species introduced to an area will not have a large impact. It is critical that we develop
the ability to predict which species will become damaging invaders, and manage
ecosystems to minimize the probability that introduced species could establish. I present
research results on the potential of the Mediterranean pine engraver, Orthotomicus erosus
(Wollaston), to utilize North American tree species as hosts. I confirm that several North
American conifers, species of pine and spruce, are suitable for the development of O.
erosus. I then investigate the host acceptance behaviors of adults in contact with the
outer bark. I show that differences among species occur during boring into the outer
bark, and that beetles bore into both suitable and unsuitable tree species. The behavior of
beetles before they are in contact with the bark was investigated with an olfactometer;
odors from several conifer species do not affect the behavior of adult beetles. I also test
the feeding response of beetles to extracts of bark and phloem chemicals. Several
extracts contain feeding incitant or stimulant compounds, but the presence of these
compounds in various tree species is different than adult bark boring behavior on those
species. Finally, I used the data from my previous experiments and the phylogenetic
distance among tree species in an attempt to predict the response of O. erosus to a second
set of tree species from independent validation experiments. Phylogenetic distance from
species with known beetle responses was not a good predictor of beetle response to novel
plants. This body of work shows that O. erosus may accept a larger set of trees than are
suitable for reproduction. Furthermore, adult host acceptance behavior is not determined solely by gustatory stimuli. Detailed knowledge about the stimuli governing host
acceptance behavior is needed to predict the acceptability of new tree species to the
beetle. The presence of acceptable but developmentaly unsuitable plants may determine
whether species such as O. erosus are able to establish in a new environment.
University of Minnesota Ph.D. dissertation. June 2009. Major: Entomology. Advisors: Robert C. Venette and Stephen A. Kells. 1 computer file (PDF); xvi, 176 pages.
Walter, Abigail Jan.
Potential host use by the Mediterranean Pine Engraver on Novel Tree Species..
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