Plants produce flowers for one reason only – to attract pollinators, such as bees, butterflies and other insects, which go from flower to flower in search of a nutritious meal of nectar and pollen. As they feast, their bodies get dusted with the plant’s powdery pollen – fine grains containing sperm cells produced by the male part of the flower. When the insect alights on another plant, some of the pollen on its body brushes off and finds its way to the female part of a new flower, enabling fertilization to take place. The result is seed and the next generation of plants.
Scent acts as a long-range signal carried on the wind and, once on the final approach to a flower, an insect is guided in by a barrage of visual clues, such as colour and shape. Flowers have evolved a vast range of scents to attract insects. Once an insect learns that a particular smell is associated with a reward, it just keeps coming back for more. Floral scents sometimes mimic an insect’s pheromones (the chemicals used to attract a mate for reproduction), in which case an insect might think it’s in for more than just a meal. Sometimes a scent mimics other things, which aren’t always pleasant. Owl-midges, for example, are attracted to the strange flowers of lords-andladies (Arum maculatum) by a faecal smell, suggesting the ideal place to lay their eggs.
