Host trees: Its primary host is lodgepole pine, however in
B.C. the MPB attacks ponderosa, western white and whitebark
pines.
Description and life cycle: Adult mountain pine beetles are
hard, stout-bodied, cylindrical, brown-black insects ranging
in length from 3.5 to 6.5 mm. In general, the mountain pine
beetle has a one year life cycle. Adults fly and attack susceptible
trees in late July through August. Trees produce large amounts
of resin toxic to the beetle when attack occurs. In order for
insects to successfully overcome the defence mechanisms of
a tree, large numbers of beetles must aggregate and attack
within a very short time frame (mass attack). Attacking beetles
introduce a blue stain fungus that combined with gallery construction
kill the tree. Females initiate attack by burrowing under the
bark and emitting a pheromone that attracts males. Once the
tree is full of beetles, anti-aggregation pheromones are released
thereby ceasing further attack.
After mating, females tunnel upwards and lay eggs on alternate
sides of the gallery. When the eggs hatch the larvae mine out
horizontally from the main gallery. Eggs hatch in 2 weeks and
1st instar larvae mine perpendicular to the parent gallery.
The mountain pine beetle develops through 4 instars, overwintering
as 3rd instar larvae.
Development is completed the following spring. Mature larvae
excavate a chamber and pupation occurs in early to mid-summer.
Pupae moult to immature (callow) adults. Beetles then feed
on the blue stain fungi within the pupal chamber for up to
2 weeks prior to emerging. Finally, from mid to late July,
mature beetles bore out of the bark and attack new hosts, thereby
completing the cycle.
