Honeybees Taste With Their Claws, No Sweet Tooth Necessary
Insects have hair-like structures on their body known as sensilla, which are sensitive to different substances because they have specialized receptor nerve cells. The sensilla on honeybee are distributed across antenna, the mouthparts, and the end part of the legs (or the tarsi). According to a new study published in Frontiers in Behavioral Neuroscience, the open access journal, honeybees process food-related information using their two front tarsi. In other words, honeybees taste with their claws.
Like Us on Facebook
The scientists exposed hundreds of honeybees to sweet, bitter, and salty solutions to identify whether or not they liked the taste. The solutions were actually applied to the tarsi on the forelegs of the bees to see if this stimulated them in a reflex action to extend their tongue to drink or retract their tongue. The study revealed that tarsi in honeybee legs are sensitive to sweet taste. They readily extend their tongue to even diluted sucrose solutions. In fact, the scientists found that the double claw at the end of tarsus is most sensitive to sweet tastes, based on measurement of nerve cell activity. In addition, the researchers determined that the tarsomeres — the segments of the tarsus before the claws — are quite sensitive to salty taste.
Honeybees rely on a range of sense data including smell, taste, memory, and color vision to find nectar and pollen in the constantly changing environment of their colony, according to Dr. Martin Giurfa, Director of the Research Centre on Animal Cognition, and one of the lead authors of the study.
"The high sensitivity to salts of the tarsomeres and to sugar of the tarsal claws is impressive given that each tarsus has fewer sensilla than the other sense organs," said Giurfa in a press release. "The claw's sense of taste allows workers to detect nectar immediately when they land on flowers. Also, bees hovering over water ponds can promptly detect the presence of salts in water through the tarsomeres of their hanging legs."
Since a range of data can impinge upon honeybees from their different sense organs, the scientists wondered what they would do if they received contradictory information. For instance, what would they do if their right foreleg informed them about a tasty source of sucrose and the left foreleg warned of distasteful caffeine? The information from both sides, according to the scientists, is processed unequally by the central nervous system. In other words, the information that comes in first — whether good or bad — counts for more. So, if the honeybee tasted sucrose first on one side, it would give priority to this taste while ignoring the other contradictory input that is distasteful. It would then instantly extend her tongue.
© 2012 iScience Times All rights reserved. Do not reproduce without permission.