In late August and September, using leaves from the same branches, the polyphagous North American swallowtail butterfly species Papilio glaucus L. (Lepidoptera: Papilionidae) is shown to select mature dark green leaves of their host plants white ash, Fraxinus americana L. (Oleaceae) and tulip tree, Liriodendron tulipifera L. (Magnoliaceae) rather than the pale green or yellowish- green mature leaves in laboratory oviposition arenas. In early August, similar results were observed for black cherry, Prunus serotina Ehrh. (Rosaceae). Dark green leaves were preferred over light green and yellowish green leaves. These green leaves of black cherry were the most nutritious leaves for larval growth indicating a clear correlation between adult preference and larval performance on this plant. However, tulip tree leaves in the summer did not elicit different oviposition responses between green and light green leaves. A field evaluation of oviposition preferences for young expanding reddish leaves of red bay, Persea borbonia (L.) Spreng (Lauraceae) versus slightly older expanded green leaves of the same branch also suggested avoidance of “young” red leaves in Florida by Papilio troilus L. and Papilio palamedes Drury during the spring season (March-April)
