Ants learn geometry and features.

Rats trained to relocate a particular corner in a rectangular arena systematically confound the correct corner and the diametrically opposite one--this rotational error demonstrates the use of the geometry of space (i.e., the spatial arrangement of the different components of a visual scene). In many cases, geometric information is preferentially used over other spatial cues, suggesting the presence of a dedicated geometric module located in the parahippocampus and processing only geometric information. Since rotational errors were first demonstrated in 1986, the use of the geometry of space has attracted great interest and now seems to be widespread in vertebrate species, including humans. Until now, rotational errors have only been considered in vertebrate species. Here, for the first time, rotational errors are demonstrated in an insect. Our results, similar to those obtained with vertebrates, can be parsimoniously explained by a view-based matching strategy well known in insects, thereby challenging the hypothesis of a "geometric module" located in the animal's brain. While introducing a new concept of flexibility in the view-based matching theory, this study creates a link between two major topics of animal navigation: rotational errors in vertebrates and view-based navigation in insects.