Saturday, January 22, 2011

Willow Pine Cone Gall

Looks like a pine cone doesn't it?

Willow Pine Cone Galls
If you notice these "pine cones", the incongruity of seeing them on bushes, without pine needles, will surely pique your curiosity, as it did mine.  These are Willow Pine Cone Galls caused by gall midge larvae (Rabdophaga strobiloides).  Not only is the gall's appearance a curiosity, but so is the gall maker's ability to manipulate the willow to grow such a unique abode.  Equally fascinating is the larva's overwintering strategy.

These little orange larvae survive the winter by freeze avoidance, or supercooling.
Basically its juiced up with antifreeze.

Here is one snug in the base of the center groove, under the white semi-transparent sheath.
Last night in the sub-zero temperatures even the river froze.  But not the larvae of the Willow Pine Cone Gall Midge and many other insects.

  For an overview of winter survival strategies see Bernd Heinrich's book ,

 I would also recommend another resource that covers the wide-ranging signs of invertebrates.


  1. I certainly have noticed these galls. But I've never opened one. Wow. That is quite the structure, and a whole lot of insulation for that little larva.