Saturday, December 20, 2008

Pollination of plants by insects


by Rudy SCHEIBNER,
Extension Entomologist

Pollination is a process by which plants receive pollen from other plants of the same species, so they can reproduce by forming seeds. Some plants are pollinated by the wind, and some are pollinated by insects or other small animals. When the plants are pollinated by insects, it looks like some kind of agreement was reached, after which the facility will provide insect with anything, if insect will pollinate the plant flowers in return. Although the plant and the insect can take advantage because of their connection to each other, the insect visits a flower usually not targeted pollinate the flower.

Honey Bees are very important insect pollinators. Most of the time, both honey bees and the plants they visit, is beneficial. The honey bee get some food and equipment get pollinated. When a honey bees collect pollen from the anthers (male reproductive part) of a flower, it brings the pollen in special pollen baskets on its hind legs. All that pollen will be taken back to the hive of bees' use. The honey bees is a messy producer of food, and some pollen gets stuck on the hairs of her body. When bien visit the next flower, some of the pollen brushes off the flower, and if it sticks to the stigma (female part) of the flower, pollination will take place. Bien does not make any effort to put the pollen in the right place.

Bees also collect pollen from corn, grain but gets nothing in return. Corn is pollinated by the wind. When honey bees try to get nectar from a flower alfalfa, the flower has a tripping device, which merges the bees in the face with one, too (the pollen-bearing part of a flower). It is the flower on the way to ensure that its pollen being attached to an insect to transfer to another flower. Bees do not like being slapped in the face, so they usually find some other kind of plant to get nectar. Some of the bees learn to chew a hole in the side of the flower and get to the nectar through the side door. When they do that pollination occurs not because the pollen on the bees do not reach the top of stigma. So it seems that the only reason for a bee visit a flower is to get what it wants and not to perform a pollination service. Pollination occurs as a happy accident of the flower.

Many other kinds of insects as wasps, flies, beetles, thrips and other types of bees, feeding on nectar or pollen also pollinate flowers by accident. However, there are at least some insects, who deliberately make sure that the flowers they visit get pollinated. The way a Yucca flower is built, it may not be pollinated in the ordinary way, and it depends on the special service of a Yucca moths to do it. When the moths come to a Yucca flower assemble a ball of pollen, and then goes to the ovaries of the female part of the flower, where it includes some eggs. Then rises to the top of the female part of the flower and puts the ball of pollen on the stigma where it is due for pollination to occur.

Now that it is pollinated, the flower can produce seeds in her ovary. The Yucca moth larvae eat some of the seeds, but many are left over to produce new Yucca plant. Because Yucca moth larvae eat only Yucca seed, and Yucca plant is pollinated only by Yucca moths, both moth and the plant will depend on each other for survival. www.uky.edu

( The image from www.landcareresearch.co.nz)

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