An online resource based on the award-winning nature guide

Rusty Tussock Moth Egg Case

There are many species of tussock moths, and in their larval, or caterpillar, stage, most are covered with tufts of hair-like setae, some impressively long.  The female rusty tussock moth, Orgyia antiqua, is flightless, so after emerging from her cocoon, she stays put, releasing alluring pheromones and awaiting the arrival of a male suitor.  After mating, she lays up to several hundred eggs on top of her empty cocoon and then dies.  The flat-topped, cylindrical eggs (with a dark depression on their top) overwinter, and as soon as leaf buds start opening, the eggs hatch, with ready-made meals inches away.  Larvae feed on the leaves of birches, oaks, crabapples and black cherry, among others.  Pictured is an egg mass on an apple leaf.


6 responses

  1. Elizabeth

    What a beautiful work of art.

    April 3, 2012 at 12:10 pm

  2. Hi Mary-
    Any chance you could add a photo of a tussock moth to this piece? That would be very helpful in completing a good overview of these creatures. Thanks!

    April 3, 2012 at 1:45 pm

  3. mmwm

    Thank you! I have one on my crabapple and kept meaning to find out what it was and whether I should leave it or not. I just removed it, as the crabapple is little and can’t take defoliation yet. Is it possible to affix it in some way to another tree, like a mature birch or apple?

    April 3, 2012 at 3:42 pm

    • Could you tape the leaf that the cocoon/eggs are on to a birch branch? (duct tape might work, even in the rain?)

      April 3, 2012 at 7:13 pm

  4. Hi Mark,
    Unfortunately, I don’t have one, but you can find several images at this website:

    April 3, 2012 at 6:40 pm

  5. Another fascinating post Mary. Thanks for sharing!

    April 4, 2012 at 12:10 am

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s