Many continue to eat the old shell for nourishment. There are between ten and twenty thousand species of butterflies in the world. One of the smallest is the Western Pigmy Blue that is found in the U.S. and has a wingspan of about one centimeter. Butterflies use their vision and scent glands to attract and find mates.
Different species emit different attractive odors called pheromones.
These odors may be detected from one to two km away. When mating, the male and female remain paired with their abdomens connected from 15 minutes to as long as three hours. Some adult butterflies visit many types of flowers for nectar while others are more picky about the flowers they choose for food. Butterflies have four wings. There are two forewings and two hindwings.