"The caterpillars of Regals, as is true of most fritillaries, eat only violets. In particular, Regals prefer the Birdsfoot Violet (Viola pedata) and Prairie Violet (Viola pedatifida). The eggs are laid in late summer. The newly hatched caterpillars overwinter and begin eating the following spring. They are black and yellow with short, branching, spiny hairs. The adults emerge in early summer and may be seen through September. Only one generation appears in a year."