Saturday, July 11, 2009

Quaking aspen, longhorn beetles, and the wildlife that love them

Based on searches directing people to this blog, adult aspen borers (Saperda calcarata) are very active in people's yards and on their quaking aspen (Populus tremuloides) trees right now. The insects themselves are fascinating, beautiful and downright crazy-looking. And although I love the intrinsic value of having the borers using the trees in our yard to complete their life-cycle, the complexity of their relationship to other species is enormous. As I have mentioned, aspen are probably the most important plant species in our yard for attracting and providing the needs for diverse species of insects and birds.

The photo above is of an adult Lorquin's Admiral (Limenitis lorquini) in the picture it is feeding on the sap from the damage the larval borers cause. Likely it is also drawn to the aspen to lay eggs; Populus species are the host plant for Lorquin's Admiral caterpillars.
Adult borer activity probably peaked in our yard a week or so ago, but a few adults (see below)can still be found mating and gravid females laying eggs (like the one above). I have received some wonderful comments from people (some on some blog posts and some via email), that are finding a new appreciation for these animals.


  1. How unfortunate! I would rather they run another Michael Jackson Tabloid article than to malign a native insect.

    By the way, thanks to the brushpile, I have almost no japanese beetles in my yard. The brush piles have attracted robins, wrens, chickadees, and, for the first time ever, a woodthrush! We found one shivering, sorry group of japanese beetles, gathered miserably on a leaf in the middle of a raspberry patch.

    My garden vegetables are untouched.

    I'm still working on that snag idea. I found a large piles of wood, left over from a construction project but they wouldn't let me have a snag!! :(

  2. It is fascinating they they interact with each other so much!

  3. We have just discovered these borers on our quaking Aspen. Do they pose any threat to the tree?

  4. Anonymous,
    Yes, the borers will eventually kill the aspen, though it might take 3 years or 10 or 15 years. And in that time, the aspen will sucker and grow new aspen. I think the whole thing is well worth it for what the aspen provide to the garden, and the wildlife that use it and eat it.
    Here is some more information:

    So, my suggestion is to let the whole process play out. Pay attention to all that happens now that you have the borers in the garden. It is really interesting educational and entertaining.
    I hope this is helpful.