Honeybees are one of the most essential species on earth for their role in pollination. In a recent discovery, scientists see for the first time how efficient their tiny tongues are at drinking any type of nectar.
Unlike other animals that drink hastily out of thirst, like cats and dogs, honeybees dip their tongues in nectar precisely and efficiently. All nectars are different - some are like a thick syrup and others are less viscous due to lower sugar content.
Bees drink nectar rapidly by sticking their tongue, which is covered with tiny hairs, in and out of nectar. They also suck less viscous nectar, which is the first time that scientists have discovered this, believing that bees could only retrieve nectar in one way.
Professor David Hu of the Georgia Institute of Technology had previously 'thought that insects' mouths were like tools in your kitchen drawer (straw, fork, spoon), e.g., with single uses.' He was not part of the current experiment but acknowledged the discovery of Jianing Wu saying that study 'showed that honeybee tongues are like a Swiss army knife, able to efficiently drink many types of nectar.'
Ways of Drinking
Engineer Wu, who also specializes in biophysics at Sun Yat-sen University in China, is the co-author of the paper published in the journal Biology Letters. Alongside his team, they saw how efficient honeybees extracted nectar by 'flexibly switch[ing] the feeding strategy from lapping to suction.'
Video recordings of bees reveal how they alternate from one way of drinking to another. When the honeybees were given a runny syrup made of 10% nectar, they used suction to extract the solution. When the nectar substitute was 50% pure nectar, which made it more viscous, the bees switched to lapping.
They adjust according to the nectar of the different flowers they visit to make honey. During a single trip, honeybees visit around 50 to 200 flowers collecting nectar and pollen until their stomachs are filled.
Alejandro Rico-Guevara, who studies nectar-eating birds and is head of the University of Washington's Behavioral Ecophysics Lab helped Wu with the experiments. He shared that a honeybee's flexibility in switching between drinking methods mean that they prefer less viscous nectars. 'This has implications at many different scales, from pollination, for our food, all the way to the role they have in natural ecosystems.'
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Maximizing Efficiency
He also noted that the bees were highly sensitive to the viscosity of nectar, immediately switching to a different method if the nectar became less or more syrupy. 'They switch at the exact point you would expect, to get the best reward for the energy invested,' Rico-Guevara explained.
Moreover, Wu explained that in thick nectars, the thousands of tiny bristles on the bee's tongue also adjust 'simultaneously at a certain angle for trapping the nectar.' After the bee pulls back its tongue inside the mouth, an internal mechanism pumps the thick nectar off the tongue and into the stomach. When the nectar is more watery, they keep their tongues in the nectar and switch to the suction mode with the pumping mechanism working at the same time.
Bees can carry their own weight in nectar. If they get a little hungry on the journey back to the hive, they can extract a small amount of gathered nectar into their digestive tract. Dr. Hu said that the switching of drinking behavior makes sense since bees are generalists - they feed on different types of flowers every day.
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