ABSTRACT
This chapter reviews knowledge of the role that floral odors play in insect-flower associations, with special emphasis on empirically obtained evidence; the circumstantial evidence is covered. Volatiles emitted by flowers and vegetative plant parts belong to similar major classes of compounds; however, the volatile profiles of flowers are generally distinct from those of a plant's foliage or fruits. Flowers may differ from other plant parts in the identity of major and minor volatiles, as well as in the relative proportions of individual constituent volatiles. The chemical composition of flower fragrances varies widely from species to species in terms of both the number and identity of volatiles. Fragrances generally comprise blends of compound classes, including isoprenoids, benzenoids, and aminoid compounds. Floral volatile emissions follow daily cycles, and their temporal correlation with pollinator activity points to an important role of flower aromas in attracting pollinators. Periodicity in fragrance emission is especially striking in species that rely for pollination on night-flying insects.
