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Cytogenetic and nucleolar meiotic cycle analyses in Dysdercus imitator Blote, 1931 (Pyrrhocoridae, Heteroptera) from Argentina

100%

Bressa M. J., Papeschi A. G., Fumagalli E., Van_Doesburg P. H., Larramendy M. L.

Folia Biologica

2003

vol. 51

issue 3-4

135-141

So far, only seven and five species of Dysdercus from the Old and New Worlds, respectively, have been cytogenetically analysed. They all have holokinetic chromosomes and a pre-reductional type of meiosis. In the present study the chromosome complement, male meiosis and nucleolar meiotic cycle of Dysdercus imitator were analysed. During male meiosis several cytogenetic features are remarkable, namely the presence of a long diffuse stage after pachytene, the finding of one or two ring bivalents per cell in almost all specimens, and the presence of several prenucleolar bodies lasting up to telophase II. The origin and function of these prenucleolar bodies could be related to a particular physiological cycle of the meiocytes.

Chromosome numbers, sex determining systems, and patterns of the C-heterochromatin distribution in 13 species of lace bugs (Heteroptera, Tingidae)

100%

Grozeva S., Nokkala S.

Folia Biologica

2001

vol. 49

issue 1-2

29-41

The karyotypes, sex chromosome systems, and male meiotic patterns in 13 species belonging to 10 genera of the family Tingidae were studied. Data on eleven species, one subgenus, and 5 genera are presented for the first time, and the chromosome formula of Acalypta parvula is revised. Karyotypes of all species included six pairs of autosomes. Most of the species displayed an XY sex chromosome system, in four species, belonging to genera of Acalypta and Kalama, the X0 system was found. Male meiosis is chiasmatic for autosomes. Sex chromosomes are achiasmatic and undergo pre-reductional meiosis. Using C-banding technique, for the first time constitutive heterochromatin was localized on chromosomes in all the species studied. The heterochromatin was found either in telomeres or in some species in interstitial locations, evidencing that a quite substantial redistribution of chromosome material within chromosomes might occur without fragmentations or fusions. In two species, a supernumerary (B) chromosome was found. In addition, the male reproductive system of four species was examined and the number of testicular follicles was determined as two per testis.

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2 Folia Biologica

1 2003

1 2001

1 Bressa M. J.

1 Fumagalli E.

1 Grozeva S.

1 Larramendy M. L.

1 Nokkala S.

1 Papeschi A. G.

1 Van_Doesburg P. H.

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Cytogenetic and nucleolar meiotic cycle analyses in Dysdercus imitator Blote, 1931 (Pyrrhocoridae, Heteroptera) from Argentina

Chromosome numbers, sex determining systems, and patterns of the C-heterochromatin distribution in 13 species of lace bugs (Heteroptera, Tingidae)