Fig. 4: Life cycle of C. elegans, and relevant muscular changes with each stage.

L1, newly hatched larvae show few mitochondria, dense bodies (Z-discs), ER, SR and no M-lines. L2, after 12 h larvae show an increase in mitochondria, dense bodies, ER, SR and first M-disk appears. L3, muscle begins to become more complex after an additional 8 h showing a further increase in mitochondria, dense bodies, ER, SR and M-discs. L4, after an additional 8 h mitochondria, dense bodies, ER, SR and M-discs increase again for the final larval stage. After 18 h the nematode has fully matured and muscle structure is completed with a final increase in mitochondria, dense bodies, ER, SR and M-discs. This artistic illustration is based on data presented in Gieseler K et. al.‘s C. elegans cross-sectional electron microscope images75. Created with BioRender.com.