Common buckeye
Junonia coenia
Butterfly
The common buckeye is a brush-footed butterfly recognized by the large eyespots on its upper wings. Caterpillars feed on plants containing iridoid glycosides — the plantain family (Plantaginaceae, including Plantago, Penstemon, and Antirrhinum snapdragons), the vervain family (Verbenaceae, Verbena), and the acanthus family (Acanthaceae) — and sequester these compounds as a chemical defense. Adults nectar broadly on late-season composites such as asters and goldenrods, and northern populations are seasonally migratory because they cannot overwinter in hard-freeze regions.
Plants in the catalog
Larval host plants · 7
Verbenaceae (Verbena) is one of the documented iridoid-bearing larval-host families of the common buckeye; cited at genus level (Bowers 1984; UF/IFAS EENY-426).
Plantago (Plantaginaceae) is a classic documented larval-host genus for the common buckeye (Junonia coenia), whose caterpillars feed on the iridoid-glycoside-bearing foliage of plantains.
Penstemon is a documented common-buckeye host genus (Plantaginaceae); P. eatonii not individually cited, so genus-level inference.
Penstemon (Plantaginaceae, iridoid-bearing) is a documented common-buckeye larval-host genus (Calscape); P. digitalis is not species-cited, so genus-level inference.
Plantago lanceolata is a well-documented larval host for the common buckeye butterfly (Junonia coenia); its leaves are among the primary plantain hosts on which buckeye caterpillars feed, so even this weedy introduced plantain supports the next generation of a native butterfly.
Antirrhinum (snapdragon) is a named iridoid-glycoside larval host of the common buckeye; Calscape lists Antirrhinum species as Junonia coenia hosts (Plantaginaceae).
Verbena (Verbenaceae) is a documented common-buckeye host genus; V. bonariensis itself is not individually cited, so genus-level inference.
Nectar plants · 4
Goldenrod (Solidago) is a documented late-season common-buckeye nectar source; large numbers nectar on goldenrods in autumn.
Adult common buckeyes nectar on asters (Symphyotrichum); New England aster (S. novae-angliae) is documented adult forage (Mass Audubon Butterfly Atlas).
Symphyotrichum asters are documented adult common-buckeye nectar sources during the late-season migratory period.
Solidago goldenrods are documented adult common-buckeye nectar sources during fall migration.
Range
Resident or seasonal across much of the United States (the eastern half, lower Midwest, and Southwest including most of California), southern Canada, and Mexico, recolonizing northern areas each year as it cannot overwinter in extreme cold.