I’m not sure, but I think this might be the first time I’ve photographed a butterfly caterpillar. Not a bad subject to start with, as few butterflies have caterpillars that are more colorful than the Gulf Fritillary, Agraulis vanillae. A common resident in the southern states and further south, this member of the nymphalid subfamily Heliconiinae is less commonly encountered in Missouri—in fact, I had never seen (or at least noticed) these caterpillars before encountering a few feeding hungrily on the foliage of maypop (Passiflora incarnata) growing in a city park in Missouri’s southeastern lowlands. While the stunning colors of these caterpillars are a delight to human eyes, their function, as in most butterfly caterpillars, is to advertise the unpalatability of their toxin-laced bodies. In the case of this species, the toxins include cyanogenic glycosides that the larvae sequester from the tissues of their host plants (ironically these compounds are supposed to serve the same protective function for the plant that produces them, but butterflies have become master specialists at evolving mechanisms to sidestep toxic impacts).
According to my friends Richard & Joan Heitzman, long-time students of Missouri Lepidoptera, this species is a sporadic migrant that occasionally forms summer colonies in Missouri, especially in the western half of the state, until the first hard freeze destroys the colony (Heitzman & Heitzman 1987).
Heitzman, J. R. & J. E. Heitzman. 1987. Butterflies and Moths of Missouri. Missouri Department of Conservation, Jefferson City, 385 pp.
Copyright © Ted C. MacRae 2012