Ecological importance of the honey bee

Wind is the main pollinating agent. In fact, most of the forest trees, almost all grasses and grains, with the exception of some that are completely self-pollinated, and many weeds are wind-poUinated. The flowers of most wind-pollinated plants are either male or female. The male flowers produce an abundance of pollen to be transported by the wind. The female flowers usually have large stigmatic areas to receive the pollen [11]. 

Nearly 200000 animal species play roles in poflinating the 250 000 species of wild flowering plants on our planet [12]. Among them, about 1500 species of vertebrates such as birds (e.g. hummingbirds) and mammals (e.g. bats, lemurs) serve as pollinators [12]. However, the main pollinators are insects they include bees, wasps, moths, butterflies, beetles and so on. Bees are the most efficient and the only dependable pollinators, because they visit flowers methodically to collect nectar and pollen and do not destroy the flower or the plant in the process. 

Consequently, bees provide substantial benefits to the maintenance of the biodiversity and the productivity of both natural and agricultural ecosystems [13,14]. However, with regard to agricultural ecosystems, it is important to stress that only 15 percent of the 100 or so crops that feed the world are serviced by domestic honey bees, while at least 80 percent are pollinated by wild bees and other wildlife [12]. 

Unfortunately, both wild bees and domestic honey bees are in decline. Thus, for example, the number of commercial US bee colonies plummeted from 5.9 million in the late 1940s to 4.3 million in 1985, and 2.7 million in 

The loss of one quarter of all managed honey bee colonies since 1990 signals one of the most severe declines US agriculture has ever experienced in such a short period. There are fewer bee hives in the US today than at any time in the past 50 years [12]. This demise has been brought about by the spread of diseases and parasitic mites, invasion of Africanized honey bees [12], climatic fluctuations, industrialization, and exposure to pesticides and other chemicals. Xenobiotics can either poison the bees 

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