Motor Control of Phonotactic Behaviour

Motor Control of Phonotactic Behaviour

Female crickets are attracted to the male’s song. When they approach a singing male, they have to solve two fundamental tasks: they need to recognise the species-specific song pattern, and they also need to localise the sound source. I developed a fast and sensitive trackball systems to analyse the female phonotactic walking behaviour. The cricket is tethered and positioned on top of the trackball, which floats in an airstream. While walking, the insect rotates the trackball; the movement of the ball is measured with an optical sensor and provides the walking speed and direction. When testing different sound patterns, the female will walk best to those, which resemble a male calling song.

Female cricket walking on a trackball

References:

• Hedwig, B and JFA Poulet (2004) Complex auditory behaviour emerges from simple reactive steering. Nature 430: 781-785
• Hedwig, B and JFA Poulet (2005) Mechanisms underlying phonotactic steering in the cricket Gryllus bimaculatus (de Geer) revealed with a fast trackball system. J Exp Biol 208: 915-927
• Poulet, JFA and Hedwig B (2005) Auditory orientation in crickets: Pattern recognition controls reactive steering. PNAS, 102 (43): 15665-15669
• Hedwig B (2017) Trackball systems for analysing cricket phonotaxis. In: Horch HW, Mito T, Ohuchi H, Popadić A, Noji S (eds), The Cricket as a Model Organism. Development, Regeneration and Behaviour. Springer Japan, Chapter 19, pp: 303-312

When orienting towards a male calling song, crickets rapidly walk and steer towards the direction of the sound signal. In order to understand the underlying motor control, we recorded their movements during phonotactic steering using a high speed video system and analysed the leg trajectories. During forward walking leg trajectories are basically parallel to the cricket’s long axis, but during acoustic steering especially the trajectories of the front and middle legs are tilted towards the side of the incoming sound. The neural mechanism by which the sound stimulus is transformed into a motor command for walking and steering is still a crucial unsolved question.

Watch the trajectories of phonotactic walking crickets:

References:

• Witney AG and Hedwig B (2011) Kinematics of phonotactic steering in the walking cricket Gryllus bimaculatus (de Geer). JEB, 214: 69-79
• Baden, T and Hedwig B (2008) Front leg movements and tibial motoneurons underlying auditory steering in the cricket (Gryllus bimaculatus, de Geer). J Exp Biol 211: 2123-2133.