And you thought that it was we humans who had all the fun. When it comes to attracting partners to getting someone to help fertilize those eggs, most of us don’t have the allure that many plants do. They use every trick in the book to lure those birds and bees and sometimes animals to get the pollen from one’s own flower to another, or even to their own. Flowers use every trick in the book to accomplish the goal; color, aroma, motion, shape and form. Sound like that teenager next door?
Let’s look at the basics for a moment. We are going to talk only of flowering plants today. Flowering plants are everywhere, as are green plants, mosses, lichens and ferns. Many of us look at a flower and think “isn’t that a beautiful color?” When a honey bee traveling at 20 miles an hour some three or four hundred feet above your garden it doesn’t see or look for flowers. He is looking for color. Red and orange are of no interest. He can’t see them. He is blind to them. But let that bee spot a patch of yellow or violet or yellow and he will swoop down to take a look. He cannot see the flower until his is inches from the bloom – it is the color, not the flower, that attracted him. Once there, he sucks out the nectar that he needs to survive.
Nectar is a sweet, mostly sugar, liquid that is exuded from the base of many petals. For many bees, butterflies and bats, and yes, hummingbirds this nectar is a primary source of sugar. They need it for nourishment. Now, while the bee or hummingbird is fluttering its wings so that its mouth or beak can suck out the nectar the motion is rubbing against the pollen holders, the stamens. Pollen is composed of very small grains of powder and it sticks to the wings and body. As the bird moves around the flower to get the pollen from the base of several petals, it also brushes against the pistil, the female organ of the plant. The pistil is covered with a sticky substance that catches some of the pollen which flows down a long, narrow tube into the ovaries; and the eggs waiting to be fertilized. Wow! But it gets better than that. As the pollinator, the bee, bat, butterfly or hummingbird moves from flower to flower to collect the nectar, the pollen from other plants stick to the pistil and are drawn into the ovary and if the plants are compatible, we get what we all know is cross pollination. That is how we get new plants in nature, without man’s interference.
Just as we use perfumes to attract the opposite sex, so do plants. Think of the night blooming Cereus: each flower opens during the early hours and dies before dawn. Where would it be without that wonderful aroma that can be smelled for hundreds of feet. How would the insects be able to find them? Of the many they exude two different aromas, food and sex attract the pollinators. Most insects have an acute sense of smell, often better than ours. But their range is narrower. For example, one type of bee might best like the aroma of geraniums or lupines. Another might like gladioli or tulips. Fussy, aren’t they. Of course, they will go to others, but they do have their preferences. And, of course, their preferences will vary from season to season. They would starve in August if they dieted only on tulip nectar. Then there are other insects, flies and beetles and the like that like flowers that smell like rotting meat or feces. Yes, there are such flowers. Flowers may give off different aromas at different times of the day, to attract insects and birds that might be around then. And then there are flowers, and all of these things have developed after millions of years of evolution, have an aroma that attracts only one type of pollinator. Next week – shapes, landing fields and death.