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eExtension.org
   Entomology
 more...>Agriculture & Natural Resources>Entomology>

Pollen, the Golden Bounty

There are more than 240,000 species of flowering plants, which must transfer pollen from the male parts to the female parts to reproduce. This is accomplished in a bewildering array of mechanisms and manners. After my spending only a few seasons in Louisiana, it is apparent that there are plants that depend upon the wind to accomplish this. There are times when the air is literally yellow with pollen, breathing is accomplished only with an effort and all exposed surfaces are covered with the material. Nature's wind strategy produces an abundance of pollen in the air in hopes that some of the bounty will make it to the female plant. Plants that depend upon animals for pollination expend much less energy on pollen production and instead use this energy to attract the pollinating organism.

The plants attract pollinators by supplying food in the form of nectar, pollen or even small insects or spiders that were feeding on the flower. The plants may give off distinctive odors that bring in visitors. Bright colors are needed to snare the attention of some pollinators, and different colors mean different pollinators. The shapes and textures of the plants and flowers will decide which animals are able to successfully pollinate, the shapes must accommodate the anatomy of the pollinator and support its weight while it is feeding or transferring the pollen. The timing of flower opening is also responsible for rewarding the efforts of particular insects, different animals and insects will be active at different seasons and times of the day or night.

Bees have short tongues and are unable to feed on flowers with long tubes and will not visit these flowers. Bees will not pollinate red flowers since they cannot detect that color, they are instead attracted to yellow, blue and UV colored flowers. Roses and other flowers with delicate, sweet scents will attract bees. The sturdy open bowl shapes that allow easy landings and offer good support are attractive to bees. Composite flowers are accessible by use of the bees short tongues and provide good landing support. Sunflowers and others with large flat disc shaped flowers tend to be warmer and their head allows the bees to forage and pollinate without their muscles cooling off.

But what of the flowering plants that do not fulfill the needs of the honeybee? Long tubed flowers require a species of insect with a long tongue to pollinate. And what about the flowers that are red, white or even green? The color of some flowers looks like they have been left in the hot sun too long and are on the verge of spoiling. This would indicate that there are other insects involved in pollination than just the bees. Not all blooms emit sweet delicate scents, some border on the verge of nausea inducing and are reminiscent of spoiled meat. The shape and size of some flowers will not support the weight or shape of bees.

Butterflies are active during the day and are known to have good vision. Watching them you will notice that they visit flowers that are brightly colored, but not necessarily possessing or giving off a strong scent. They visit many composite flowers or clustered flowers, which they can walk around on and probe with their tongue. The tube of each flower will approximate the length of the butterfly’s tongue.

Most moths are active at night and are more dependent on their sense of smell. Observing them, you will notice them hovering like humming birds to feed. Since they hover to feed, the petals of the flowers they visit tend to be flat or bent back to allow easier access. Light-colored or white flowers that are more visible at night are their destination. These flowers may open at night and begin to release their scents then. The flowers that attract them typically emit strong sweet scents. The nectar is found at the bottom of a deep tube and the long tongue of a moth is required to reach it.

Hummingbirds, which hover when feeding, will visit flowers with petals similar to the ones visited by the moths. Most hummingbird feeders are red for a reason; hummingbirds are attracted to brightly colored flowers, especially the red ones. This is true even if the flower has little or no scent. The flowers that they visit dust their head or back with pollen.

Bats will pollinate flowers large enough and sturdy enough to stand up to being battered by the bat's head. Bats that pollinate have good vision and a good sense of smell. The flowers they visit open at night and are white or light color and emit a fruity or fermented odor. Bats will also feed on the insects visiting the flowers as well as the nectar. Bats are known to help pollinate mangoes, bananas and guavas.

Flies are attracted to rotting flesh and to flowers that mimic those characteristics. The flowers may be pale and dull with a dark reddish brown to purple color. Often they will give off an odor like rotting meat, carrion, dung or blood. The flowers may be funnel like or be a complex trap. Syrpid flies and bee flies mimic bees and wasps and though not as efficient at transferring pollen, still manage to pollinate well.

Beetles are sloppy but efficient pollinators. They deserve this description because they pollinate by consuming most of the plant parts of the flowers they visit. They find the protein, sugar food mix a good food source. The flowers they visit tend to be large, flattened and heavily scented. The pollen will be easily accessible, but often the flower will include a trap to keep the beetle moving within the flower a little longer. The plant’s ovaries are not usually easily damaged by the feeding of the beetle. Due to their sheer numbers beetles are responsible for pollinating most of the 240,000 plus flowering plants found on earth.

Honeybees are still the premier pollinator, but this is mostly due to our move toward factory monoculture farms. Other bees are more efficient pollinators on a per-bee basis. Mason bees are five to ten times better pollinators, but honeybees have bigger colonies (30,000+ bees per hive). Honeybees can forage over long distances and are easier to manage. Honeybees have been the pollinating workhorses in the U. S. for the last 400 years, tirelessly working to pollinate our food and fiber plants.

Photos in this article taken by Gary Wilson, Area Agent.

Last Updated: 4/19/2013 9:45:24 AM

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