Ants navigate the world through a rainbow of scents: the scents of their nest, nest mates and tempting food. However, when a forager follows a plume of scent to a tasty snack, it may not have learned to recognise and respond to the food's odour: it may simply be following its nose because it likes the smell. Knowing that foragers carry nectar for the colony in their crops and transfer it to hungry nest mates –– they look as if they are kissing as they sip from each other –– Yael Provecho and Roxana Josens from the Universidad de Buenos Aires, Argentina, wondered whether ants could learn to recognise food flavours picked up when sipping from a nest mate's mouth and then follow the flavour's odour in search of more of the same(p. 3221).

The duo decided to test their theory by seeing whether an ant could follow an odour in a maze after tasting the scent in sucrose supplied by a foraging nest mate. Having identified (and marked) an ant that they knew was empty and would feed from a full forager, the team paired the empty ant with a forager and released the forager into an arena supplied with tea tree flavoured sucrose solution. They allowed the forager to fill up on the tea tree flavoured sucrose and returned it to its empty nest mate so that the empty ant could take a sip of the sucrose from the forager's mouth. Then they asked the ant that had just taken a sip to choose between a tea tree scented channel and a channel scented with rose (that it had not encountered before) in a Yshaped maze.

The ant successfully chose the tea tree scent. And when the team repeated the test with other pairs of ants and different scent combinations, the insects that sipped flavoured sucrose solution from another's mouth were able to follow the flavour's scent in favour of an unfamiliar scent.

So rather than simply following tempting odours to tasty treats, ants can learn to recognise scents associated with food that have been brought to the nest, allowing new foragers to follow the scrumptious scent and forage for more.

Provecho, Y. and Josens, R. (
). Olfactory memory established during trophallaxis affects food search behaviour in ants.
J. Exp. Biol.