JoAnne Skelly column: The Magic of Pollination
Submitted by editor on Sun, 03/03/2019 - 10:36am
The purpose of all living organisms is procreation. In order to survive, creatures must create offspring. One way plants do this by making seeds. Seeds can result when pollen moves from the male anther to the female organ (stigma) of the same flower or a different flower of the same species.
This is the act of pollination, which hopefully results in fertilization of the egg(s). Seeds can only be produced when pollen moves between flowers of the same species.
In the book Brilliant Green by Mancuso and Viola, the authors write “Think of pollination as a huge market. We have buyers (insects), goods (pollen and nectar), sellers (plants), and even …advertising (the color and fragrance of flowers)!” The flowers pay for reproductive assistance by enticing their pollinators with nourishing nectar. Pollinators pay for their service by accidentally spreading pollen from flower to flower.
The tricky or magical part is that pollinators aren’t spreading the pollen to just any random flower. No, they must go from flower to flower of the same species. Mancuso and Viola query “What can induce such species loyalty?” Wouldn’t it be far easier for pollinators just to visit any arbitrary flower near another flower? The interesting thing is that insects actually “stay loyal to the first species they visit in the morning.” Entomologists call this ‘site fidelity’.
Site fidelity isn’t really practical from the insect’s survival standpoint. After all, any nectar source, no matter its origin, could be nourishing. However, site fidelity is critical for plant reproductive success. If precious pollen goes to some unintended and unrelated flower, it is useless; and energy has been wasted from the plant’s perspective. Plants have amazing mechanisms to draw in appropriate pollinators to their flowers. In general, petal shapes, scents and the colors of flowers are all designed to attract specific pollinators. Beyond that, some plants can even mimic the colors, textures or perfume of an insect female, luring in unwitting males to get the pollination job done. Other plants simulate odors the insect can’t resist, such as fermenting fruit or rotting meat. Plants may even entrap a pollinator for a period of time to ensure pollination occurs.
Plants and pollinators have co-evolved to make plant reproduction successful and have characteristics called ‘pollination syndromes’. These syndromes can help predict the kind of pollinator that might visit a flower. Go here to see a detailed chart about which plant characteristics attract which pollinators.
— JoAnne Skelly is Associate Professor and Extension Educator Emerita with the University of Nevada Cooperative Extension.
