Reproductive Isolation in Colias eurytheme and C. philodice (Lepidoptera: Pieridae) : Use of Olfaction in Mate Selection1

Abstract

The basis of mate selection in the hybridizing sulphur butterflies Colias eurytheme Boisduval and C. philodice Latreille was evaluated by treating newly emerged virgin females as follows: eyes covered with paint, antennae removed or covered with Vaseline™, and portions of antennae removed. Mature females with painted eyes mated selectively with conspecific males indicating that accurate mate selection can occur in the absence of visual stimuli. Removal of the distal ⅔ of the antennae reduced mating by C. eurytheme females after 30 minutes but increased mating by C. philodice females. Perception of olfactory stimuli through antennal receptors evidently matured when most females were 20-30 minutes old.