Ready N E, Najm R E
J Exp Zool. 1985 Jan;233(1):35-50. doi: 10.1002/jez.1402330107.
The sizes of the unifunctional dorsal longitudinal (DLM) and bifunctional subalar (SA) metathoracic flight muscles of the cricket Teleogryllus oceanicus increase by more than an order of magnitude between the second instar before the terminal molt and the tenth day of adult life. During the same developmental period isometric twitch duration (onset to 50% relaxation, 25 degrees C) varies little, while muscle mitochondrial content increased by a factor of ten as measured by stereological analysis of electron micrographs and citrate synthase activity (mumoles citrate . min-1 . gm protein-1, 25 degrees C). The wing muscles of adults have abundant sarcoplasmic reticulum (SR), narrow myofibrils, and a high volume density of mitochondria. At two molts from adulthood muscles that will later be used in flight behavior also have narrow myofibrils and abundant SR, but unlike muscles at later stages, nymphal muscles have a low volume density of mitochondria. At the terminal molt muscles have at least as much SR as is seen in muscles at the tenth day of adult life, and the myofibrils are also more narrow at the earlier stage. Since there is significant variation in muscle structure and little change in twitch duration during late development, the efficacy of the SR in releasing and resequestering CA2+ is seemingly lower in muscles at the terminal molt, a time of rapid muscle growth.
在终末蜕皮前的二龄若虫到成虫期第十天期间，海氏长蟋（Teleogryllus oceanicus）单功能的背纵肌（DLM）和双功能的亚翼肌（SA）这两种后胸飞行肌的大小增加了一个多数量级。在相同的发育阶段，等长收缩持续时间（起始到50%松弛，25摄氏度）变化不大，而通过电子显微镜的体视学分析和柠檬酸合酶活性（微摩尔柠檬酸·分钟⁻¹·克蛋白⁻¹，25摄氏度）测量发现，肌肉线粒体含量增加了10倍。成虫的翅肌有丰富的肌浆网（SR）、狭窄的肌原纤维以及高体积密度的线粒体。与成虫期相隔两次蜕皮的若虫肌肉，这些肌肉后来会用于飞行行为，也有狭窄的肌原纤维和丰富的SR，但与后期阶段的肌肉不同，若虫肌肉的线粒体体积密度较低。在终末蜕皮时，肌肉的SR至少与成虫期第十天的肌肉中所见的一样多，并且在早期阶段肌原纤维也更狭窄。由于在发育后期肌肉结构有显著变化，而收缩持续时间变化不大，在终末蜕皮这一肌肉快速生长的时期，肌浆网在释放和重新摄取Ca²⁺方面的效能似乎较低。
