Chemical Factors Determining the Choice of Food Plants by Papilio Larvae

A series of complex chemical compounds present in the essential oils of Umbelliferae impart characteristic odors to the plants of this family. Species of Papilio which feed on Umbelliferae are attracted by these chemicals. Although the attractant chemicals are most common in Umbelliferae, they occur sporadically in other families. Papilios now feeding on umbelliferous plants originally fed upon Rutaceae. The transition from one part family to the other took place because of the presence of identical attractant chemicals in both families. The present distribution of the genus Papilio is related in part to the distribution of the host plants.