Passive muscle forces in <i>Drosophila</i> are large but insufficient to support a fly's weight.

ABSTRACT: Movement of a limb is shaped by active forces generated by muscle contraction but also by passive forces within individual muscles and joints. In small animals such as insects, the contribution of passive forces to limb movement can match the active forces. However, most measurements of passive forces are limited to the femur-tibia joint in large insects. Here we take advantage of genetic tools in Drosophila to measure passive torques at multiple joints in the fly's leg. We genetically inactivate all the motor neurons to assess passive forces. We find that the passive torques are well approximated by a linear spring, i.e., the passive torques linearly increase with angular deviation from the rest angle. The torques are much larger than the gravitational torque due to the leg itself.

SUBMITTER: Wang N 

PROVIDER: S-EPMC12324252 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature