Getting a temperature is a bad thing for most mammals, but returning forager bees always warm up on the home run and a high temperature can indicate the quality of nectar or pollen that they return with. Flowers also warm up: the temperature inside a Narcissus longispathus can be 8°C higher than the surroundings. Knowing that bees sense temperatures with their antennae, James Nieh, and his colleagues Tobin Hammer and Curtis Hata from The University of California San Diego, wondered whether bees can use this thermal information about food. Can bees learn to discriminate between food sources at different temperatures (p. 3928)?

Training bees to stick out their tongues in return for a sugary reward when the team touched a warm surface to a bee's antenna, the team discovered that bees can learn to identify warmth with food. Next the trio tested whether the insects could learn to associate temperature differences with a food reward, and discovered that the bees do associate temperature differences with food. The bees' ability to recognise the temperature difference increased dramatically as the difference increased, but the insects were better at recognising warm temperature differences than cold temperature differences.

So, bees can learn to recognise different temperatures and could be guided by this information when foraging for, or receiving, food.

T. J.
J. C.
Thermal learning in the honeybee, Apis mellifera
J. Exp. Biol.