الفهرس 
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Abstract
The honey bees (Apis mellifera L.) are among the most important economic insects not only their ability to produce honey but also due to their role in pollination of many economic importance crops. The natural food of the honey bees consists of pollen and nectar or honey collected from flowers. Pollen provides bees with the main nutrients required for growth and development. Pollens contain a range of nutrients including proteins and amino acids, fats, fatty acids and sterols, carbohydrates such as sugars and starches, minerals, antioxidant and vitamins. Nectar is the main energy source for bees and consists predominantly of sugars and water.
Colony survival depends on the availability of pollen (proteins, lipids, and micronutrients) and nectar (carbohydrates). pollen intake influences lifespan and several health indicators including physiological metabolism, immune-competence, disease tolerance and pesticides resistance. On the other hand, not all pollen species have adequate nutritional composition. Some flowering plant species, including common mass-flowering crops, do not provide the necessary nutrients honey bee colonies need to survive and thrive. However, given that the main ingredient of bee bread is pollen, it seems likely that bee bread will vary in nutritional composition depending on the local and seasonal availability of pollens from different plant species.
Beekeepers have experienced yearly colony losses of up to 45%. Over recent years some regions of the world have been suffering from an increase in losses of their managed honey bee colonies. A number of different factors are considered to be involved and are now being monitored and investigated further such as pests and diseases, bee management, including bee keeping practices and breeding, the environment, including weather, agricultural practices and the use of pesticides and the availability and quality of food sources. As the result of an international effort called Prevention of honey bee Colony Losses (COLOSS), a series of surveys have been conducted from around the globe toward understanding the situation of colony losses and elucidating possible causes.