ALT Figure 3(E) RNA in situ hybridization of the spermatogonial marker ddx4, the macrophage marker mpeg1.1 and the smooth muscle marker acta2 in 12- and 27-month-old testes. Representative higher-resolution images of the boxes marked ‘i’ and ‘ii’ are shown on the left for each testis sample. Scale bars: 100 μm. Images are representative of three animals. NK, natural killer cells; SMC, smooth muscle cell; Treg, T regulatory cells.

ALT Figure 1 Cellular heterogeneity and its possible impact on tissue-wide population distributions. (A) Each cell has a unique ‘fitness value’ that differs from the fitness value of its neighbours. The difference in fitness values between cells is depicted by the degree of difference in their colours. (B,C) In specific contexts, some fitness values may be favoured over others, resulting in population skewing.

ALT Fig 1 (A) Transverse section showing L1 epicuticle (blue brackets). Image from series S.E.M._L1_4, z62, described in Witvliet et al. (2021). Scale bar: 100 nm. L1 cuticle is ∼150 nm thick. Images in A-C are from midbody regions of cuticle over dorsal or ventral muscle quadrants. (B) Transverse section showing L3 epicuticle, blue brackets. Image from series TEM_L3, z140. Scale bar: 100 nm. Red arrowheads indicate discontinuities in the outer osmiophilic layer. (C) Example of differential staining of outer cortical cuticle (orange bracket). Image captured with a TEM_L3, z196. Scale bar: 100 nm. (D) Late L4 stage (∼L4.7) animal, midbody region, showing nascent adult cuticle under detached L4 cuticle. Image is a longitudinal section across one L4 annulus and two furrows. Blue arrowheads indicate epicuticle in L4 cuticle at furrows and on sides of furrows in nascent adult cuticle; red arrowhead indicates discontinuity where adult epicuticle may have not yet formed. Scale bar: 100 nm.