Flirtatious Flowers

To woo your sweetheart, we all know to give her flowers. The beautiful colors and aromas are sure to put her in a romantic mood. But did you realize that plants also use their flowers’ colors and aromas to attract pollinators for reproduction?

Tavia Cathcart, Executive Director at Creasey Mahan Nature Preserve, gave a wonderful presentation for the Kentucky Native Plant Society at their annual Wildflower Weekend at Natural Bridge State Park this weekend. I’ve never been able to remember which flower parts are the male and which the female, but now I’ll remember the difference forever. Here it is, the staMEN has the male parts that produce pollen, while the PISTIL is the female part that will produce fruit after it is pollinated. Just think of “Annie Get Your Gun” to associate pistil and female. Don’t you wish someone had told you this in high school biology class?

Plants have adapted their flowers based on the time they bloom and the pollinators available. For example, ginger blooms in the early spring when there are few flying insects yet. Its blossom is next to the ground so ants and other ground insects can reach it. Instead of an aroma that would be attractive to us, it smells like rotten meat, which is attractive to the ants and beetles pollinating it. You have to put out the right welcome mat to attract the right pollinators.

When we talk about pollinators, most people think of bees, of course. Honey bees are the gold medals champions when it comes to pollination. They have little sacks on their legs to stuff the pollen in as they move from flower to flower. They will visit up to 500 flowers in one collection trip. A really ambitious honey bee could potentially visit up to 2,000 flowers a day. And remember, all these hard workers are female (of course!). The bees gather pollen to eat themselves, as it is very nutritious, and to feed their young. Pollinating the flower is just a by-product for them.

Some plants make it easy on the pollinators. They have open blooms, and anything walking or flying close enough will be dusted with pollen. Other plants have deep wells with nectar at the bottom, and only pollinators with long tongues (such as hummingbirds) or long proboscis (such as this nexus sphinx moth) can get a sweet drink as a reward for pollination.

Other plants give the pollinators clues that we limited humans can’t even see. Bees can see in the ultraviolet wave lengths, so plants give them landing directions to find the good stuff. Flowers present bulls-eyes and landing strips on the petals, like a flight officer guiding a jet into a safe landing on an aircraft carrier. The blue geranium is in natural light, while the one on the right is in ultraviolet light.

To avoid the competition with other flowers for daytime pollinators, some plants only bloom at night. Bats and moths will fly for miles following their aroma. Think of the millions of years spent in creating these adaptive relationships. Sometimes a plant can only be pollinated by one kind of insect or animal, and if that pollinator should die out, the plant would become extinct too. Remember, as John Muir says, When we try to pick out anything by itself, we find it hitched to everything else in the universe.

Naturally yours,