Marsh Fritillary Caterpillars

Marsh Fritillary Caterpillars

Observation - Marsh Fritillary Caterpillars - UK and Ireland. Description: This small nest of Marsh Fritillaries are the only ones I have found after the big freeze of 2010 and the wet and cold June of 2011.I am curious about the 2 redheaded specimens why so different ?

This small nest of Marsh Fritillaries are the only ones I have found after the big freeze of 2010 and the wet and cold June of 2011.I am curious about the 2 redheaded specimens why so different ?