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Scent is a chemical signal that attracts pollinators to a particular flower in search of nectar or pollen, or both. The volatile organic compounds emitted play a prominent role in the localization and selection of blossoms by insects, especially moth-pollinated flowers, which are detected and visited at night. Species pollinated by bees and butterflies have sweet perfumes, whereas those pollinated by beetles have strong musty, spicy or fruity smells.
To date, little is known about how insects respond to the individual chemical components, but it is clear that they are capable of distinguishing among complex aroma mixtures. In addition to attracting insects and guiding them to food resources within the bloom, floral volatiles are essential for insects to discriminate among plant types and even among individual flowers of a single species. For example, closely related plant species that rely on different types of insects for pollination produce different odors, reflecting the olfactory sensitivities or preferences of the pollinators. By providing species-specific signals, the fragrances facilitate an insect's ability to learn particular food sources, thereby increasing its foraging efficiency. At the same time, successful pollen transfer (and thus sexual reproduction) is ensured, benefiting the plants.