PARENT SESSION
Contributed Oral Session 3: Herbivory: Plant - Herbivore Interaction
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 513 E, Level 5, Palais des congrès de Montréal
Use of ancestral and novel host plants by the Alaskan swallowtail butterfly (Papilio machaon aliaska): Adult preference and larval performance experiments fail to reveal host races.
Murphy, Shannon1, 1 Cornell University, Ithaca, NY
ABSTRACT- Herbivorous insects account for approximately one quarter of the world's biodiversity. Much of this astounding diversification of plant-feeding insects has been driven by host shifts in which an insect population incorporates a novel plant into its diet, eventually abandoning the ancestral host plant. In order for this process to succeed, adult females need to find the novel hosts attractive for oviposition and their offspring must be able to survive and grow on these plants. I investigated a host shift within the Papilio machaon group of swallowtail butterflies. Papilio machaon aliaska uses three plant species as host plants. Cnidium cnidiifolium belongs to the family Apiaceae, the ancestral host-plant family of the P. machaon group. Artemisia arctica and Petasites frigidus, by contrast, belong to the distantly related Asteraceae family and were colonized relatively recently by this group of butterflies. When a specialized insect species uses unrelated host plants, the question inevitably arises as to whether the species is divided into host races. I tested both female oviposition preferences for the three host plant species and larval survival when reared on these host plants and did not find any evidence to support the hypothesis that P. m. aliaska individuals form separate host races.
Key words: host preference, host race, larval survival, Lepidoptera