Our insect of the week for January 12, 2026 is my all time favorite central Illinois butterfly – the buckeye (Junonia coenia). It was described by Jacob Hübner in 1822.

This species is known throughout the eastern United States. Adults are often found resting on low vegetation in open areas.

Caterpillars appear to prefer plants which produce iridoid glycosides (such as plantains and snapdragons). Presence of these compounds may also trigger oviposition behavior by females. Caterpillars feed individually and not in aggregations. They are also vulnerable to a densovirus (and provides more reason for them to feed individually).

Although this species does not have a long single migration (like the Monarch butterfly), they are susceptible to freezing temperatures. Adults fly south to overwinter in warmer states (especially Florida) in September and October. Another generation migrates northward in April through June with some individuals nearly reaching the Canadian border.

Curiously, this genus likely originated in Africa. How it migrated and evolved into the species known in North America is still being investigated (and was the subject of a dissertation in 2022 by Melanie Lalonde at the University of Manitoba).

The specimen in this photograph was collected and photographed by Frank Hitchell in Peoria County, Illinois.