The long-term goal of this research is to elucidate the roles played by plant chemistry in the ecology and evolution of a single taxon of herbivorous insects, namely the butterfly family Papilionidae. Emphasis during the next three years will continue to be placed on the chemical basis of plant recognition by oviposition males. The occurrence of contact and volatile oviposition stimulants for the black swallowtail, Papilio polyxenes (tribe Papilionini), will be surveyed in a variety of host and non-host plants to assess the specificity and variability of chemical response profiles in one insect species. Identification of oviposition stimulants from Asimina spp. for Eurytides marcellus (tribe Graphiini) will be completed for comparison with known stimulants for Battus philenor (tribe Troidini) and P. polyxenes (tribe Papilionini). Identification of stimulants and deterrents will also be carried out with P. machaon, which shows evidence of a host switch from the Apiacea to the Asteraceae (genus Artemisia) These comparative studies will permit testing of a long-held hypothesis that the evolutionary radiation of swallowtail butterflies has been constrained by the botanical distribution of particular chemical compounds that are used as behavioral cues in host recognition.
