Orientation of Polyergus rufescens (Hymenoptera, Formicidae) during slave-making raids.

We investigated the factors involved in the orientation of raiders of the European Amazon ant, Polyergus rufescensand how these factors are used by raiders during the different phases of slave-making expeditions. Ants at the head of the raiding column did not follow previously deposited chemical trails but oriented by celestial cues. Raiders in the middle of the column used celestial factors but were also strongly affected by the recruiting activity of the ants that preceded them. During the return trip, raiders used both chemical and celestial cues. The latter allowed the ants to assume the correct home direction while following the chemical trail. Perception of the ultraviolet band of the light spectrum was of crucial importance for the orientation of the raiders, during both the outbound and inbound journeys. This supports the hypothesis that P. rufescens workers, like other ants, perceive the pattern of polarized skylight in the ultraviolet range.Copyright 1997 The Association for the Study of Animal Behaviour