In recent years, honeybee populations worldwide have dramatically declined, threatening agriculture. One possible cause could be the foods that beekeepers are giving their charges.
“Now artificial pollen substitutes — commonly consisting of protein sources derived from soy, wheat or lentils — are widely used as nutrition supplements in agricultural systems,” Chen said. “Although the supplemental protein diets offset the poor nutritional conditions in honeybee colonies, long-term consumption of protein as the sole nutrient may compromise the ability of plant miRNAs to fine-tune honeybee development.”
Prior research has also shown that artificial pollen substitutes were not sufficient to boost a bee’s cellular immunity against parasitic infections. Given these determinations, the researchers now advise beekeepers not to use artificial pollen substitutes as the sole diet for their bees.
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The impact of plant miRNAs on bees is so powerful that it might have even affected their evolution into social insects. Chen explained that the ancestors of bees were likely burrowing wasps that lived in the middle Cretaceous Period, when non-avian dinosaurs were still in existence. As flowering plants emerged during the Tertiary Period (2.6-66 million years ago) so too did the social behavior among bees.
Chen said that microRNAs also can influence human gene expression.
“However,” he added, “it doesn’t necessarily mean that pollen miRNAs will also inhibit ovary development or fertility in humans. For one thing, unlike honeybees, pollen is not the major food source for humans, hence ingested pollen microRNAs would be well below the amount required for any physiological effect.”
Studies on hunter-gatherer diets, however, find that our ancestors for tens of thousands of years often included numerous vegetables, fruits, and starches — such as tubers — in their diets. They additionally frequently consumed a lot of honey, as did the ancient Egyptians and other early cultures.