The Eastern Tailed Blue Butterfly is a native of North America that feeds on native legumes as a caterpillar. Recently, Hesler reported* populations of Eastern Tailed Blue Caterpillars, Cupido comyntas causing defolation of soybean in South Dakota. Caterpillars were scattered, populations were low and defoliation was noticeable, but not enough to impact yield. Pupae were found on soybean leaflets.
Soybean is native of Asia and this is the first report of Cupido comyntas feeding. Hesler noted that the caterpillars, like many species of blue butterfly caterpillars, were tended by ants. It will be interesting to learn if this occurrence is localized to South Dakota or more widespread.
Louis S. Hesler. 2014. First record of soybean as a host plant of a subspecies of the eastern tailed-blue, Cupido comyntas comyntas (Lepidoptera: Lycaenidae). Insecta Mundi. 0330: 1-5.