RT Journal Article SR Electronic T1 Static stability predicts the continuum of interleg coordination patterns in Drosophila JF bioRxiv FD Cold Spring Harbor Laboratory SP 374272 DO 10.1101/374272 A1 Nicholas S. Szczecinski A1 Till Bockemühl A1 Alexander S. Chockley A1 Ansgar Büschges YR 2018 UL http://biorxiv.org/content/early/2018/07/23/374272.abstract AB During walking, insects must coordinate the movements of their six legs for efficient locomotion. This interleg coordination is speed-dependent; fast walking in insects is associated with tripod coordination patterns, while slow walking is associated with more variable, tetrapod-like patterns. To date, however, there has been no comprehensive explanation as to why these speed-dependent shifts in interleg coordination should occur in insects. Tripod coordination would be sufficient at low walking speeds. The fact that insects use a different interleg coordination pattern at lower speeds suggests that it is more optimal or advantageous at these speeds. Furthermore, previous studies focused on discrete tripod and tetrapod coordination patterns. Experimental data, however, suggest that changes observed in interleg coordination are part of a speed-dependent spectrum. Here, we explore these issues in relation to static stability as an important aspect of interleg coordination in Drosophila. We created a model that uses basic experimentally measured parameters in fruit flies to find the interleg phase relationships that maximize stability for a given walking speed. Based on this measure, the model predicted a continuum of interleg coordination patterns spanning the complete range of walking speeds. Furthermore, for low walking speeds the model predicted tetrapod-like patterns to be most stable, while at high walking speeds tripod coordination emerged as most optimal. Finally, we validated the basic assumption of a continuum of interleg coordination patterns in a large set of experimental data from walking fruit flies and compared these data with the model-based predictions.Summary statement A simple stability-based modelling approach can explain why walking insects use different leg coordination patterns in a speed-dependent way.ϕIIpsilateral phase relationshipϕIContralateral phase relationshipAEPAnterior extreme positionBLBody lengthCOMCenter of massICPInterleg coordination patternIRInfraredLEDLight-emitting diodePEPPosterior extreme positionPPPolypropylenew1118D. melanogaster white mutant strainWTD. melanogaster wildtype strains Berlin and CantonS