Suitability of four families of Florida "bay" species for <i>Papilio palamedes</i> and <i>P. glaucus</i> (Papilionidae)

We tested the suitability of four Florida "bay" plant species for larval growth and adult opposition preferences for two swallowtail butterfly species, <i>P. palaniedes</i> and <i>P. glaucus</i>. Much confusion exists about the host plant records for these butterflies in the literature. We confirmed that of the four bay species tested, only red bay (<i>Persea borbonia</i>) of the Lauraceae was suitable to support larval survival and growth of <i>P. palamedes</i>. All <i>P. palamedes</i> larvae offered sweethay (<i>Magnolia virffniima</i> of the Magnoliaceae), Loblolly bay (<i>Cordonia lasianthus</i> of the Theaceae) or Southern Bayberry (<i>Mijrica cerifera</i> of the Myricaceae) died as neonates. Conversely, only sweet bay (<i>Magnolia</i>) was suitable for supporting survival ofneonate <i>P. glaucus</i> larvae, with red bay, loblolly bay and bayberry unacceptable or toxic. Oviposition preferences (individually assessed in a revolving four-choice arena) were strongly in favor of the most suitable host for each species: sweet bay received 93.9 of the total <i>P. glaucus</i> eggs and red bay received 54.2 of the total P. palanwdes eggs. The generally low level of adaptation of the <i>Lauraceae</i> specialized spicehush swallowtail, <i>Papilo troilus</i>, to red bay was evident in that all nine Florida females refused to oviposit on any of the four "bays" (including red bay).