How Plants Use Elaborate Flowers to Attract Pollinators

When looking at beautiful blossom, few realize that a flower is just a big, showy advertisement used to help plants have sex. No kidding! Fancy flowers are very energetically expensive for a plant to produce, and their sole purpose is to attract pollinators; insects, birds and mammals that spread pollen (plant sperm) from flower to flower.

Mutualism of Pollination

The relationship between plant and pollinator is win-win (a mutualistic symbiotic relationship in 'biology speak'). The plant offers nectar, purely as a bribe, to entice pollinators into its flowers. When the pollinator contacts the flower, to obtain the sweet treat, some pollen will drop on the nectar nibbler. Then, when the pollinator moves on to raid the sweet stores of another flower (usually visitng the same species of flower, since many pollinators are specialists), some pollen from previously visited flowers with fall, potentially fertilizing the flower that the pollinator is currently visiting.

Bees and Pollination

Think about the hard-working bees you've seen moving from flower, to flower, to flower. They are gathering nectar and pollen to bring back to the hive. Although bees do steal some of the pollen for their own purposes, what also happens when they visit flower is that the little bee 'hairs' all over their little bee body become dusted with pollen. Showy flowers absolutely rely on pollinators. No pollinators, no fertilized plants, no seeds and therefore, no new plant.

Mimicry - Sex, Lies and Orchid Flowers

Some flowers have gotten so good at this pollination game, that their flowers have evolved to trick pollinators into visiting, even though the flower provides no nectar. A full one-third of orchid species are maters of deceit. They have blossoms that may, to us, appear beautiful if not bizarre, but to the species of insect that pollinates them, the flower looks (and smells) like a mate! The plant is in effect duping the insect, enticing it to pollinate with the false promise of sex. Now that's a smart flower!

Wind Pollination and Plain Jane Flowers

Plants that are pollinated by wind typically have flowers that are so plain, it is difficult to even tell that they are flowers. This spring, take a look at the oaks, maples and many other trees. They do have flowers, but prepare to be unimpressed. This is another smart plant strategy. If you are a plant fertilized for free by wind blowing pollen your way, why invest in those expensive, showy blossoms.

Sources

Campbell, N. & Reece, J. (2002) Biology, Sixth Edition. Benjamin Cummings.
Krogh, D. (2009) Biology: A Guide to the Natural World. Pearson Benjamin Cummings.