Fig. 1

Male meiosis in different Triatoma sordida subcomplex species (2n = 20A + XY). (a-c-e-g-i): C-banding. (b-d-f-h-j): Fluorescent in situ hybridization with 45S ribosomal DNA probe. a-b: T. guasayana a: Metaphase I (MI). All autosomal bivalents and the X chromosome are euchromatic while that the Y appears C-heterochromatic. b: Metaphase II (MII). rDNA signals are located in one autosomal bivalent (arrow). c-d: T. garciabesi c: MI. C-heterochromatin distribution similar as observed in T. guasayana (d): M I. Ribosomal signals on the X chromosome (arrow). e-f: T. sordida sensu stricto. e: MII. Seven autosomal pairs exhibit C-blocks while 3 pairs are euchromatic (f): MI. rDNA signals on the X chromosome (arrow). g-h: T. sordida Argentina. g: MI. All chromosome complement is euchromatic, except for the heterochromatic Y chromosome. h: MI. Ribosomal signals on both sex chromosomes (arrows). i-j: T. sordida La Paz. i: MII. Eight autosomal pairs present C-blocks, while 2 pairs are euchromatic. j: MII. rDNA clusters on one autosomal pair (arrow). Bar = 10 μm