The mountain pine beetle’s ability to survive extreme cold is the subject of a new study from the University of Northern British Columbia.
“Mountain beetle overwinter as larvae mainly and they can withstand some pretty cold temperatures, some figure down to about minus 40 Celsius. It is amazing they can survive that underneath the bark of a tree,” said UNBC Ecosystem Science and Management Professor Dezene Huber, the principal investigator in the study.
Huber said a popular misconception about the pine beetle is that northern winters are no longer cold enough to kill the insect.
“While the overall depth of winter cold is important, the timing of deep cold snaps — how early or late the cold happens — is more important.”
The study examined what proteins are present in mountain pine beetle larvae in early and late autumn, compared to early spring and late spring, to see if the protein present related to genes being turned off or on. If a gene gets turned on, then that protein related to that gene gets made in the insect’s body. Proteins will, depending which proteins there are, do things such as help to produce certain antifreeze compounds, like glycerol, or may help the insect to cope with physiological stress that it’s experiencing as it goes into the cold. Or in the spring, it may take some of those compounds it has made and reconvert them into energy so the larvae can complete its development into an adult.
“What we did is take the first look at everything that’s going on inside of mountain pine beetle as it heads into winter and as it leaves winter. Now we have a really good 30,000-foot view of all sorts of different things that are happening in the complex physiology of this insect and it gives us in our lab a lot of interesting questions to chase down,” Huber explained.
In the larger scheme of things the lab also works quite closely with people who that are modelling the expansion of the outbreak into Alberta that can use information related to insect physiology to try and determine where the mountain pine beetle is going to spread next, specifically over the Rocky Mountains and into the jack pine forests of Alberta.
“Or how climate change may allow it to spread further or into areas that it’s never gone into before,” Huber explained.
The study was conducted in collaboration with other researchers from the Tria Project from thet Universities of British Columbia, Alberta, and Minnesota and the Natural Resources Canada Canadian Forest Service.
Funding for the project was provided by Genome Canada, Genome BC, Genome Alberta, the Canada Research Chairs Program, the Canada Foundation for Innovation, and the BC Knowledge Development Fund.
“Because of our integration with other groups it’s hoped that the data will be shared widely. We have made the study an open article so all of the data involved is available to anybody in the world, including industry, and other scientists,” Huber said. “Hopefully people are able to grab it and make use of it one way or another.”
Up until this point in time, the only thing known for certain about mountain pine beetle overwintering, other than some of its temperature minimums and a few other things, was that it used glycerol as an antifreeze compound.
“This study points to all sorts of different things related to the physiological development of the insect so there are all sorts of different directions to go with it. I see this paper as hub and from that research our group and other groups will take off. I can’t even predict where it will go because our group will look at it from one angle but other people will look at it from a different perspective,” Huber said.
Prior to the most recent mountain pine beetle epidemic, researchers in B.C. did not have the benefit of genomics research, but have had access to other “excellent,” research based on ecological and population-based studies.
“This time the insect broke out into a different scientific context where we actually have different scientific tools to look at it. So we’ve been able to take the excellent foundation of previous research and now we have this new tool and we’re able to overlay that tool on the previous research, understanding what we know about the behaviour and physiology of this insect and find new things, which hopefully are able to help us currently as the pine beetle spreads into Alberta and in 20 or 30 years if this happens again,” Huber said.
He also hopes it will help to understand parallel types of insect outbreaks such as spruce beetle or other creatures.
“The amount of work that has gone into the mountain pine beetle in the last decade is pretty unbelievable, but we know a heck of a lot more than we ever did in the past. It’s probably one of the best researched insects in the world,” he said, adding it doesn’t mean a magic bullet will be discovered any time soon to manage it perfectly.
As scientists move toward understanding better how to manage insects like the mountain pine beetle, the world is also challenged by more uncertainty because of climate change.
“There are two prongs to this thing. We know more about it than ever but we there’s also a lot more going on than ever with the insect,” Huber said.
Huber’s article can be viewed at: www.sciencedirect.com/science/article/pii/S0965174812001221.