ABSTRACT
The amount, composition and location of heterochromatin in Athaumastus haematicus (Stål, 1859), Leptoglossus impictus (Stål, 1859), Phthia picta (Drury, 1770) (Coreidae), Largus rufipennis Laporte, 1832 (Largidae) and Jadera sanguinolenta (Fabricius, 1775) (Rhopalidae) are analyzed by C-banding and DAPI/ CMA fluorescent banding. As the rule for Heteroptera the possession of holokinetic chromosomes and a pre-reductional type of meiosis cytogenetically characterize these five species. Besides, all of them (except L. rufipennis) present a pair of m chromosomes. C-banding technique reveals the absence of constitutive heterochromatin in A. haematicus, scarce C-positive blocks in L. impictus and J. sanguinolenta, and C-positive heterochromatin terminally located in P. picta and L. rufipennis. All C-bands are DAPI bright, except for a DAPI dull/CMA bright band at one telomeric end of the X chromosome in L. rufipennis, which probably corresponds to a nucleolar organizing region. The results of the banding techniques are analyzed in relation to the chiasma frequency and distribution in the five species, and it is concluded that there should exist some constraints to the acquisition and/ or accumulation of heterochromatin in their karyotypes.