Main Content

Activity of locust brain neurons exposed to the natural sky

Many insects rely on sky compass signals for spatial orientation, e,g. during homing or seasonal migrations. Laboratory experiments in bees, beetles, locusts, crickets, butterflies and flies suggest that the central complex in the insect brain serves a role as an internal sky compass, signaling heading directions relative to the azimuthal direction of the sun. Laboratory settings, however, cannot imitate the natural conditions of a sun-lit sky which provides compass information through the position of the sun, a brightness and chromatic gradient, as well as a pattern of polarized light. We therefore set out to use extracellular wire recordings to study the responses of locust brain neurons during exposure of the animal to the full sky. Activity changes during passive 360° rotation of the animal will be compared with neural responses during laboratory stimulation with polarized light and an “ersatz-sun”. These experiments are aimed to critically test the validity of laboratory experiments in understanding the sky compass network in the insect brain.