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Tuesday, March 20, 2012

Creature Feature: Mountain Pine Beetle.

Sometimes the deadliest things in the world are the ones we don't even see. For example, until today's class, I had no idea a certain beetle species existed. It turned out to be a native species that, thanks to subtle human activity, was running absolutely wild.

The mountain pine beetle (Dendroctonus ponderosae) is native to western North America. It ranges from British Columbia, Canada, all the way down to Mexico. True to its name, it bores into many a pine species in order to lay its eggs.

How the MPB lays eggs in pine trees is particularly nasty: first, obviously, the female beetle makes a hole in the tree. Then, she lays her eggs in there. They are not alone: they are accompanied by a fungus called "blue stain fungus" that shields the eggs from the tree's immune system. Once the larvae hatch, they spend the bulk of their lives beneath the bark, only emerging as adults to start the cycle all over again. They're also hard to detect; pine trees can remain green for a year after being infested.

Despite being native, this beetle has been wreaking havoc on North American forests. Normally, these beetles would only target damaged or dead trees. Now that there are no more cool temperatures to keep them at bay, they have to lay in live trees. After causing damage in its native range, it has moved onto other temperate forests. It makes the Japanese beetle problem look tiny by comparison.

Let's put those two into perspective, shall we? The Japanese beetle eats leaves from a variety of plants. The mountain pine beetle kills trees from the inside-out. Only the latter will result in more ground erosion, leading to the total collapse of North American forests. We have sparrows and other birds taking Japanese beetle blooms as a shiny green smorgasbord; the mountain pine beetle, however, will only diminish in numbers when it runs out of pine trees to eat. It has predators, but they likely will not be able to keep up.

This invasion has a mean ripple effect. Remember, climate change caused these beetles to overpopulate to begin with. Trees keep CO2 down. Less trees means more CO2, which means more climate change, which might mean more beetles. Even with pheromone baits and various pesticides being used to control these things, "we're screwed" is the appropriate reaction.

All too often, the media focuses on damaging species that freak us out. This is understandable since journalists are out to sell news. This little bug is bigger than giant pythons in terms of potential damage.


  1. Not even a faint hope? Surly someone somewhere is putting in some effort to stop this.

  2. They're putting in an effort - as I said. pheromone traps and various pesticides. The problem is that bugs adapt quicker than, say, anything with a spinal cord.

  3. You know a few good forest fires would probably help. Maybe they could set some controlled burns in these areas pictured and... oh wait nature decided to do it herself. Too bad we're putting them all out.