Papilio aegeus Donovan (Lepidoptera: Papilionidae) host plant range evaluated experimentally on ancient angiosperms

Chemical similarities among ancient Angiosperms presumably played a role in the ecological and evolutionary diversification of the swallowtail butterflies (Papilionidae). The abilities of neonate larvae of the Citrus swallowtail, Papilio (=Princeps) aegeus (from Queensland, Australia), to eat, survive and grow on leaves (a choice of young and old) of 34 plant species from families of ancient Angiosperms; 8 Rutaceae, 3 Magnoliaceae, 13 Lauraceae, 3 Monimiaceae, 1 Aristolochiaceae, 2 Apiaceae, 1 Sapotaceae, 1 Winteraceae and 2 Annonaceae were tested. It was apparent that there is genetic variation in populations of Rutaceae-specialised Australian P. aegeus for acceptance, consumption and larval growth, reflecting differential suitability of some native Australian Lauraceae species as food plants (as well as certain Winteraceae, Monimiaceae and non-Australian Magnoliaceae, Lauraceae and Annonaceae). No consumption or survival of P. aegeus was seen on Aristolochia elegans (Aristolochiaceae) or Pouteria australis (Sapotaceae) despite literature records alluding to this possibility. The Rutaceae specialist P. aegeus appears to have the fundamental detoxification capabilities for processing many existing species of the basal Angiosperm families, without having direct ancestors that historically had fed on them.