Ants’ Capability of Adding and Subtracting Odors

Abstract

Summing and discriminating odors may be useful for animals in their daily life. The workers of the ant Myrmica sabuleti rely essentially on odors for navigating and have a rather poor visual perception. It was previously shown that they can add and subtract visual elements when the result of the operation has been concretely presented to them, i.e. they thus respond to an image which corresponds the best to that they have memorized. Here we examined if these ants can sum two odors and ‘subtract’ (discriminate) an odor from a mixture of two ones. They added two distinct odors only when these odors were presented side by side and perceived simultaneously, and not when they were located at some distance from one another and perceived consecutively. They discriminated one odor from a mixture when that odor was presented in association with a reward (the food). They subtracted one odor from a mixture when that specific odor was presented and perceived separately at a place not associated with a reward. Myrmica sabuleti workers could thus effectively add two odors and subtract one odor from a mixture, but only when the odor(s) to which they should respond was (were) associated with a reward. In the wild, such a behavior could help the ants to navigate.