“These insects must kill the host tree to reproduce,” Erbilgin says.

To monitor beetle infestations and possibly curb their spread, Erbilgin’s team has created a synthetic version of this aggregation pheromone and put it into pine trees. The team can then estimate the total beetle populations in a given area based on the number of beetles they trap within a fixed period of time. “If you trap something like 1,000 beetles, you should be concerned,” Erbilgin says.

But there’s a catch: once a tree becomes overpopulated with beetles, females make an abrupt attitude adjustment and begin to emit a new anti-aggregation pheromone that actually repels the beetles in order to reduce competition for resources and potential mates.

Erdilgin says they’ve experimented with using a synthetic version of this second pheromone to see if they can repel the beetle from certain areas, but they weren’t happy with the results. “You’ve got to be careful; you might repel the beetle from one area and the beetles will start killing trees elsewhere.”

Beyond monitoring, he says there is little use these methods could have in stopping the kind of beetle epidemic that has infested lodgepole pines in British Columbia. But the aggregation pheromones could possibly control the spread of smaller populations of the beetle such as those that target jack pine in Alberta.

But for now the process is still expensive and labour-intensive, and Erbilgin says controlling the beetle’s spread is an upward battle.

“Dealing with these tree-killing mountain pine beetles is more difficult than killing cancer,” he says. “There are something like a trillion of these beetles and they are good flyers — they fly over the Rocky Mountains.”