Sunday, April 1, 2012

Essentials for your pollinator garden: sap, moths and beetles.

This time of the year, the best thing you can have in your pollinator garden is sap.  There are probably lots of ways to come up with a sap feeder, but the easiest one is to let borer beetles and clearwing moths do their job- more on this in a minute.
Adult popular clearwing moth (Sesia tibialis), a yellowjacket mimic
In my garden, butterflies often owe their early spring survival to some unlikely sources- the larvae of aspen borer beetles and poplar clearwing moths.
Adult aspen borer (Saperda calcarata)
These larvae tunnel through quaking aspen (Populus tremuloides), which kills the trees, but the journey provides so much along the way (I've written a lot about this relationship- click here for more information).  As one response to the attacking insects, aspen force sap out of the tunnels.
Larvae of the aspen borer beetle (Saperda calcarata)
Over the last couple of weeks we've had several butterflies in the garden including a few Milbert's  Tortoiseshell (Aglais milberti) and even a Mourning Cloak (Nymphalis antiopa, our state butterfly) yesterday afternoon.  Judging from local blogs, Facebook, and actual interpersonal communications with people, other "out and about"  Missoulians are noticing them, too.

You may be wondering what they the butterflies ares eating, because if you have been looking around for the last few weekend, you'll have noticed that not much is flowering yet.  As a result, this is one of the most critical times of the year to support butterflies in your garden (or at least attract butterflies to your yard).On warm March days you can see the sap running (slowly) out of the holes in the trees, and when the first butterflies emerge this is where they go to eat.
An adult Lorrquin's admiral (Limenitis lorquini) feeds on sap on our aspen .
What butterflies need is a food source timed for their survival.  When many of our overwintering butterflies emerge from their hibernacula they are hungry.  With not much of anything flowing now the best food source is sap.

If you want pollinators, plant a lot of native plants and get out of the way!


  1. Great example of the incredible timing between phenomena in native plants and animals. Thanks for sharing this.

  2. Hi
    We've found wood boring lavae in the park cloe to us. They look like the aspen borer but a little bigger. They leave a hole filled with sawdust or wood pulp about 4mm dia. Wound it be of interest if i can get some photos to put on here. Also, how can these be delt with so they don't destroy every tree in the park.