Insects Pollinating Plants
Just as mating is essential for the continuity of the animal kingdom, pollination is vital for reproduction in plants. Pollination is defined as the transfer of pollen grains from the male part of a flower to the female part of the same flower or of another flower (Australian Museum). There are two types of pollination; self-pollination which involves transfer of pollen from the stamen to the pistil of the same plant but not necessarily the same flower, cross-pollination involves pollen and pistil from entirely different plants but of the same species. For pollination to take place some agents must be present to effect the process, the main agents are wind, water, and insects. Also referred to as pollinators, insects aid in pollination by moving pollen from anthers to stigma of flowers. The plants aided by insects in pollination are referred to as insect-pollinated plants; these plants have unique adaptations for the process.
Adaptations of Insect Pollinating Plants
Visual and Olfactory Cues
Insect pollinating plants possess unique adaption features that make them susceptible for pollination by insects. They posses flowers with brightly colored petals. Insect pollinating agents, majorly the bees and butterflies are attracted to bright colors. In their search for nectar, they travel long distances and one of their key identifiers of flowers is the color. Once an insect spots a flower, they immediately move to them to search for nectar and in the process aid the plant in pollination. Insect pollinating plants also have flowers with sweet scents to attract the insects’ attention (Yoon et al, p.111-116). Some insect pollinators have well developed senses of smell and other than the bright colors; they are attracted to the plants by the sweet scent of their flowers and in the process aid in pollination.
Shape and Size of Flowers
Insect pollinated plants have large flowers that are uniquely shaped to facilitate pollination. For instance, the milkweed (Asclepias) plant has flowers that provide little landing platform for nectar seeking insects. For this reason, insects seeking to sap nectar from the flower must rest on the stigmas and anthers of nearby flowers. In the process, they transfer pollen from anthers to stigma and from flower to flower and thereby effect pollination.
Rewards to the Pollinator
After an insect has made its first landing on the flower due to color and scent attraction, the flowers need to remunerate them so that they may be able to visit nearby flowers for more rewards and in the process carry pollen from plant to the next. These rewards are in terms of nectar, pollen, and behavior.
Nectar is produced by parts of a flower identified as nectarines. Nectarines may randomly on a flower; they are essentially epidermal regions consisting of permanently-open stomata. They posses vein endings that constantly unload sugar from the plant phloem. This sugar mixes with water that is a result of osmosis making up a sugary liquid that emanates through the stomata. This nectar accumulates at the base of the flower prompting insects to navigate through the flower to gain access and in the process aid in pollination (Australian Museum).
Some insect pollinators, such as bees and beetles feed on pollen. Therefore, insect pollinated plants usually produce large amounts of pollen for the extra function of feeding the pollinators. Pollen is a source of nutrients for insects. Additionally, this pollen is usually sticky to glue to the wings and legs of the pollinators.
Some insect pollinated plants have flowers that have developed behavioral characteristics that take advantage of the pollinators. For instance, the lady-slipper orchids have petals that have evolved into some kind of pouch, which trap fragrance and chemicals that attract insects. Once insects land on the flower, the fall into the pouch and are intoxicated by the aroma. They stumble for some time before making their way out through the opening from which light streams and in the process make contact with pollen sac. When they move to the next flower, the pollen on their bodies is deposited on the stigma and thus pollination is enhanced.
Economic Value of Insect Pollination
Scientific statistics show that insect pollination is of high economic value, for instance, in 2005, bees contributed €153 billion in terms of the crops that fed the world. This was estimated to 9.5% of the global agricultural production (Helmholtz Association of German Research Centres). Therefore, insect pollination is significant in global agriculture and efforts should be made to conserve the pollinators.
Pollination simply put is the transfer of pollen grains from anthers to stigma of a flower or between flowers in a plant. Insects are an essential agent of pollination and their economic value to agriculture cannot be overshadowed. Insect-pollinated plants are those plants that rely on insects as the main agents of pollination, they posses unique adaptive characteristics for the process. These adaptations include, brightly colored and scented flowers, possession of nectar, large quantities of sticky pollen, and unique behavioral tendencies. Since insect pollination of invaluable significance in the field of agriculture, it is highly recommended that efforts be made to protect insect pollinators as their disappearance would be of far reaching consequences to the global economy.
Australian Museum. Pollination. 16 November 2010. 16 April 2014 <http://australianmuseum.net.au/Pollination>.
Helmholtz Association of German Research Centres. “Economic Value Of Insect Pollination Worldwide Estimated At U.S. $217 Billion.” ScienceDaily, 15 September 2008. <www.sciencedaily.com/releases/2008/09/080915122725.htm>.
Yoon, Ji-Young, et al. “Residue Patterns of Indoxacarb and Pyridalyl in Treated Cauliflower.” Agricultural Sciences 4.3 (2013): 111-6. ProQuest. Web. 18 A