Caterpillar on poplar leaves
Sun, May 17, 2009 at 1:49 PM
I found these caterpillars on poplar leaves in our field in WNY. I rescued them from the hard freeze we are going to have tonight. I have been unable (yet) to identify them and for curiosity sake I wondered what they may be>
Western New York

White Admiral Caterpillar

White Admiral Caterpillar

Hi Mark,
Your caterpillars belong to a butterfly in the genus Limenitis, most likely the White Admiral, Limenitis arthemis arthemis.  The species, Limenitis arthemis has three subspecies, and the White Admiral is the northern subspecies in the east.  Further south the most common subspecies is the Red Spotted Purple and in the western U.S. the dominant subspecies is the Western White Admiral.  The three subspecies will interbreed where their ranges overlap, giving way to subspecies intergrades.  BugGuide has a wonderful information page on this species.  The caterpillars also feed on the leaves of cherry, willow and birch.

One Response to Probably White Admiral Caterpillar

  1. indroid says:

    Hi Bugman,

    Your admiral is actually a viceroy; (Limenitis archippus archippus); not
    a white admiral. It’s an understandable mistake; since caterpillars and life
    histories of the two are very similar; but, the yellowish-greenish cast of the
    fifth instar viceroy caterpillars coupled with the protrusions at the base of the thoracic horns serve to differentiate the two species.

    Also, the most common species in the Western U.S. is shared between the lorquin’s admiral (Limenitis lorquini) and the weidemeyer’s admiral Limenitis weidemeyeri . The western white admiral, Limenitis arthemis rubrofasciata barely enters into the U.S. through Northern Montana, North Dakota, and possibly Minnesota where intergrades between it and nominotypical L. arthemis may occur.

    For more information about how to rear varying Limenitis taxa, click
    Thx, Todd

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