It carries the male reproductive cells of plants, and its nutritional composition varies considerably between species. Testing What Bees Really NeedResearchers compared the essential amino acid composition of honeybee tissues with pollen from 99 UK flowering plant species representing 26 plant families. The team then produced artificial diets based either on the amino acid composition of different pollens or on the composition of honeybee tissues. Most of the pollen profiles did not closely match the nutritional composition of the bees themselves. How Amino Acids Control AppetiteThis pattern led the researchers to investigate histidine, an essential amino acid that bees require in relatively small amounts.