Mountain pine beetle jumps tree species

Apr. 7, 2011 – Mountain pine beetle (MPB)
is on the move, not just from one tree to another, but across tree species. A
group of researchers, funded in part by Genome Alberta, have conclusive
evidence that MPB is now invading jack pine. The usual host for MPB is
lodgepole pine. Now that the beetle has crossed over to another host, it could
move further east across the boreal forest.

It has long been suspected that the beetle was invading hybrid tree species,
but using newly developed DNA genotyping and location data, the University of
Alberta team found that pure jack pine are being attacked by the beetle and
the blue-stain fungus the beetles brings into the tree. The discovery was
largely due to the work of University of Alberta molecular ecologist Catherine
Cullingham and co-researchers, authors of a paper published online recently in the journal Molecular
Ecology, entitled Mountain pine beetle host-range expansion threatens the boreal forest.

“Tracking the pine beetle’s progression and telling jack pine from the hybrid
species took a lot of work,” says Cullingham. “Our research team used molecular
markers to conclusively show that the latest pine species to be attacked are
indeed jack pine.”

University of Alberta Researcher Janice Cooke, who is a co-author of the paper, points out that jack pine is
the dominant pine species in Canada’s boreal forest, ranging east from Alberta
all the way to the Maritimes. The paper suggests that apart from the new host
species opening up a new range for the beetle to attack, the risk could be made
worse by future climate change.

“Forest managers now have to recognize the fact that before there was a
barrier, as the beetle occurred only in lodgepole pine, but now it is occurring
into the boreal, so it can continue spreading,” says Cullingham. "Forest managers in Saskatchewan,
Manitoba, and Ontario are going to have to be cognizant of this potential and
the potential impact on their forests."

The current Mountain Pine Beetle outbreak has affected over 14 million hectares
of forestland in western Canada. It is the largest outbreak documented since
record taking began 125 years ago.

The research was funded by Genome Alberta, Genome British Columbia, and Genome
Canada.