Insect inertial measurement units: Gyroscopic sensing of body rotation

Abstract

All flying insects require both visual and mechanosensory information to effectively control flight in complex environments. Sometimes, however, visual systems may not have sufficiently short response times to accommodate for rapid perturbations in the flight path. Thus insects also rely on fast and precise mechanosensory systems as part of their flight control mechanism. We review a subclass of mechanosensory systems that serve as gyroscopic organs - otherwise known as inertial measurement units in engineering systems. We review current neurophysiological and behavioral data for two putative biological gyroscopes: cranefly halteres and the antennae of hawkmoths. In addition we present data that further clarifies the gyroscopic function of moth antennae, showing that they directly measure pitching motions. We also introduce new data on mechanosensory systems in the wings of moths and suggest that these too could provide critical inertial sensory information to flying animals.