FISH using 18S rDNA (green) and telomeric TTAGG (red) probes on male (a, b, d, g, h) and female (e) karyotypes and silver staining (c, f, i). Diplotene of Pholidoptera (a–g) and Uvarovistia (h, i) species. White arrows point to rDNA clusters on the medium acrocentric pair or on the bi-armed first pair of autosomes. Black arrows indicate the active NOR co-localized with rDNA. a P. fallax and b, c P. pustulipes (2n = 31). Asterisks point to differences in size/strength of rDNA/NOR between homologous chromosomes d–f P. macedonica (2n = 29). Arrows indicate high-intensity rDNA signal and NOR located in the paracentromeric region of the bi-armed first pair of autosomes g P. brevipes (2n = 29). Arrows point 18S rDNA cluster on medium-sized bivalent h, i U. satunini (2n = 31). Bar = 10 µm.