J. coenia life history
Common Buckeye (Junonia coenia) Life History

Egg, 10-29-12

Recently emerged, 10-31-12

First instar, 11-1-12

Second instar, 11-4-12

Third instar, 11-7-12

Fourth instar, 11-9-12

Fifth instar, 11-16-12

Sixth instar, 11-24-12

Chrysalis, 11-28-12

Fresh Common Buckeye ventral, 12-09-12

Fresh Common Buckeye dorsal, 12-09-12

A captive Common Buckeye deposited several eggs on Runyon's Violet Wild Petunia, Ruellia nudiflora. The caterpillar featured here emerged two days after the egg was found. The first instar lasted 4 days; instars 2-5 lasted 2-3 days each. The surprise came when the caterpillar went into a sixth instar; I expected only five. I have read that sometimes diapausal caterpillars have an extra instar. There was no diapause here, but perhaps November's (relatively) cooler weather and a shorter photoperiod triggered the sixth instar. The rest of the eggs eclosed 2-3 days after this one. The caterpillars developed at varying rates,  but all had six instars.

Inset: face of final instar, 11-23-12.

41 days passed from the time the first egg was found to the time the first adult emerged. The fresh adults were spectacular, with varying amounts of blue sheen on  the forewings (or, in one case, on all four wings).

This study was my third experience with Common Buckeye caterpillars. The first group was almost orange; the second, orange and black; this group was almost black. Clearly, the caterpillar coloration is highly variable. The same is true of the pupae. In every case the caterpillars had blue iridescence at the base of each spine. Under certain fluorescent lighting, the iridescence became a beautiful purple.

Common Buckeye Page