Overwintering caterpillars of the Red Spotted Purple (Limenitis a. astyanax), Viceroy (Limenitis archippus), White Admiral (Limenitis arthemis), Weidemeyer's Admiral (Limenitis weidemeyeri), and/or Lorquin's Admiral (Limenitis lorquini) requires that you create a safe environment from predation where hibernacula are exposed to sufficient humidity and airflow.

If you live in the midwestern or Eastern U.S., this can be accomplished by pinning hibernacula to the branches of its host plants which include black cherry (Prunus serotina), willows (Salix spp.) , or deerberry (Vaccinium stamineum) so that the larvae can crawl out in the spring to resume feeding.  Watch youtube video.

Once hibernacula are pinned to these trees, it is strongly suggested that you place a caterpillar sleeve around the hibernaculum to protect it.  (These can be purchased or homemade.)