Tu M, Dickinson M
J Exp Biol. 1994 Jul;192(1):207-24. doi: 10.1242/jeb.192.1.207.
Of the 17 muscles responsible for flight control in flies, only the first basalar muscle (b1) is known to fire an action potential each and every wing beat at a precise phase of the wing-beat period. The phase of action potentials in the b1 is shifted during turns, implicating the b1 in the control of aerodynamic yaw torque. We used the work loop technique to quantify the effects of phase modulation on the mechanical output of the b1 of the blowfly Calliphora vicina. During cyclic length oscillations at 10 and 50 Hz, the magnitude of positive work output by the b1 was similar to that measured previously from other insect muscles. However, when tested at wing-beat frequency (150 Hz), the net work performed in each cycle was negative. The twitch kinetics of the b1 suggest that negative work output reflects intrinsic specializations of the b1 muscle. Our results suggest that, in addition to a possible role as a passive elastic element, the phase-sensitivity of its mechanical properties may endow the b1 with the capacity to modulate wing-beat kinematics during turning maneuvers.
在负责苍蝇飞行控制的17块肌肉中，已知只有第一基翼肌（b1）在每个翅膀搏动周期的精确相位都会产生动作电位。在转弯过程中，b1中动作电位的相位会发生变化，这表明b1参与了气动偏航扭矩的控制。我们使用工作循环技术来量化相位调制对丽蝇Calliphora vicina的b1肌肉机械输出的影响。在10赫兹和50赫兹的循环长度振荡期间，b1产生的正功输出幅度与之前从其他昆虫肌肉测得的幅度相似。然而，当在翅膀搏动频率（150赫兹）下进行测试时，每个周期内完成的净功为负。b1的抽搐动力学表明，负功输出反映了b1肌肉的内在特殊化。我们的结果表明，除了可能作为被动弹性元件的作用外，其机械性能的相位敏感性可能使b1有能力在转弯机动过程中调节翅膀搏动运动学。
