Impact of central complex lesions on visual orientation in ants: Turning behaviour, but not the overall movement direction, is disrupted

Abstract

Wood ants are excellent navigators using a combination of innate and learnt navigational strategies to travel between their nest and feeding sites. Visual navigation in ants has been studied extensively, however, we only know little about the underlying neural mechanisms. The central complex (CX) is located at the midline of the insect brain. It receives sensory input that allows an insect to keep track of the direction of sensory cues relative to its own orientation and to control movement. We show here direct evidence for the involvement of the central complex in the innate visual orientation response of freely moving wood ants. Lesions in the CX disrupted the control of turning in a lateralised manner, but had no effect on the overall heading direction, walking speed or path straightness.

Rotation of skylight polarization during learning walks is necessary to trigger neuronal plasticity inCataglyphisants

“…This makes the CX a suitable candidate for a memory-based calibration of visual compass cues, which is also supported by the learning-dependent volume increase of the CX shown in our present study. The differences in the synaptic architecture and behavioural function of the CX and mushroom body visual pathways inferred from circuit analyses and ablation experiments suggest that view-based panoramic information is stored in the mushroom bodies, whereas directional information is processed in the CX [ 12 , 13 , 29 , 39 , 40 ]. It is not possible with the methods currently available to quantify distinct synapses or pre- and postsynaptic elements within subunits of the CX (as it is possible for synaptic MG in the mushroom bodies) for exploring the exact source of volume increase.…”