We analyzed patterns of heterochromatic bands in the Neotropical stingless bee genus Melipona (Hymenoptera, Meliponini). Group I species (Melipona bicolor bicolor, Melipona quadrifasciata, Melipona asil6ae, Melipona marginata, Melipona subnitida) were characterized by low heterochromatic content. Group II species (Melipona capixaba, Melipona compressipes, Melipona crinita, Melipona seminigra fuscopilosa e Melipona scutellaris) had high heterochromatic content. All species had 2n =18 and n = 9. In species of Group I heterochromatin was pericentromeric and located on the short arm of acrocentric chromosomes, while in Group II species heterochromatin was distributed along most of the chromosome length. The most effective sequential staining was quinacrine mustard (QM)/distamycin (DA)/chromomycin A 3 (CMA 3 )/4-6-diamidino-2-phenylindole (DAPI). Heterochromatic and euchromatic bands varied extensively within Group I. In Group II species euchromatin was restricted to the chromosome tips and it was uniformly GC + . Patterns of restriction enzymes (EcoRI, DraI, HindIII) showed that heterochromatin was heterogeneous. In all species the first pair of homologues was of unequal size and showed heteromorphism of a GC + pericentromeric heterochromatin. In M. asil6ae (Group I) this pair bore NOR and in M. compressipes (Group II) it hybridized with a rDNA FISH probe. As for Group I species the second pair was AT + in M. subnitida and neutral for AT and GC in the remaining species of this group. Outgroup comparison indicates that high levels of heterochromatin represent a derived condition within Melipona. The pattern of karyotypic evolution sets Melipona in an isolated position within the Meliponini.

We describe the karyotypes of eight bee species of the genus Melipona and compare them in terms of heterochromatin content and location (C-banding technique). All species had 2n = 18 (females) and n = 9 (males) chromosomes, but a wide variation in heterochromatin content was detected among karyotypes. On the basis of these differences, the species were divided into two functional groups, one of them comprising species with a karyotype having a low heterochromatin content (M. bicolor bicolor, M. quadrifasciata, M. marginata, and M. asilvai), and the other species with a high heterochromatin content (M. seminigra fuscopilosa, M. capixaba, M. scutellaris, and M. captiosa). In the species with high heterochromatin content, heterochromatin occupied practically the entire extent of all chromosomes, with euchromatin being limited to the extremities, a fact that prevented observation of the centromere. In contrast, in the species with karyotypes having a low heterochromatin content, heterochromatin was visualized only in some chromosomes. In the chromosomes in which it was present, heterochromatin was located in the centromere or on the short arm. M. bicolor bicolor had the smallest heterochromatin content with only three chromosome pairs presenting heterochromatin in females. Increased heterochromatin content may be explained by interstitial and pericentromeric growth.
Este trabalho descreve os cariótipos de oito espécies de abelhas do gênero Melipona, relacionando-os por meio do conteúdo e localização da heterocromatina (técnica de banda C). Todas as espécies estudadas apresentaram 2n = 18 (fêmea) e n = 9 (macho) cromossomos, entretanto encontrou-se uma grande variação no conteúdo de heterocromatina entre seus cariótipos, o que permitiu separá-los em dois grupos funcionais: um reunindo espécies de cariótipo com baixo conteúdo de heterocromatina (M. bicolor bicolor, M. quadrifasciata, M. marginata e M. asilvai) e o outro com cariótipo de alto conteúdo heterocromático (M. seminigra fuscopilosa, M. capixaba, M. scutellaris e M. captiosa). Nas espécies com alto conteúdo de heterocromatina, esta ocupa quase toda a extensão de todos os cromossomos, ficando a eucromatina restrita às extremidades, o que impossibilitou a observação do centrômero. Contrariamente, nas espécies de cariótipos com baixo conteúdo, a heterocromatina foi evidenciada somente em alguns cromossomos. Naqueles em que ela está presente, sua localização foi centromérica ou foi evidenciada no braço curto. A espécie que apresentou menor conteúdo heterocromático foi M. bicolor bicolor, sendo que na fêmea apenas três pares de cromossomos apresentaram heterocromatina. O aumento no conteúdo de heterocromatina pode ser explicado pelo crescimento intersticial e pericentromérico

Melipona mandacaia is a stingless bee endemic to northeast Brasil. We describe the M. mandacaia karyotype using C-banding technique. fluorochrome staining and treatment with restriction enzymes and discuss the position of this species in the context of the phylogeny of the genus. Melipona mandacaia has 2n = 18 (14 SM + 2 M + 2 A). Heterochromatin was detected in the pericentromeric region of pairs 1, 2 and 8 and in the form of small blocks in the remaining pairs. Staining with base-specific fluorochromes showed that this heterochromatin was rich AT (QM and DAPI), except in the region corresponding to the NOR which was rich GC (CMA3) and was cleaved by the HaeIII enzyme. Melipona mandacaia is a member of Group I Melipona. Treatment with DraI/Giemsa discloses a larger number of bands than treatment with DraI/QM. Pre-cleavage with DraI gave rise to a larger number of bands following QM staining; a circumstance evidently due to a removal of the DNA-protein complex that prevented the association of the fluorochrome with AT-rich DNA. The results highlight the complex nature of heterochromatin.

The aim was to broaden knowledge on the cytogenetics of the subtribe Meliponina, by furnishing cytogenetic data as a contribution to the characterization of bees from the genus Oxytrigona. Individuals of the species Oxytrigona cf. flaveola, members of a colony from Tangará da Serra, Mato Grosso State, Brazil, were studied. The chromosome number was 2n = 34, distributed among four chromosomal morphologies, with the karyotype formula 8m+8sm+16st+2t. Size heteromorphism in the first metacentric pair, subsequently confirmed by sequential staining with fluorochrome (DA/DAPI/CMA3 ), was apparent in all the examined individuals The nucleolar organizing regions (NORs) are possibly located in this metacentric chromosome pair. These data will contribute towards a better understanding of the genus Oxytrigona. Given that species in this group are threatened, the importance of their preservation and conservation can be shown in a sensible, concise fashion through studies such as this.

Stingless bees are distributed widely in the tropics, where they are major pollinators of several plant species. In this study, the karyotype of Meliponaquinquefasciata Lepeletier, 1836 was analysed, with emphasis on the presence of B chromosomes. Post-defecating larvae were analysed using Giemsa staining, the C-banding technique, sequential staining with fluorochromes, and FISH. The chromosome number ranged from 2n = 18 to 22 (females) and from n = 9 to 13 (males) due to the presence of 0–4 B chromosomes. This result demonstrates that M.quinquefasciata has the same chromosomal number as other Melipona Illiger, 1806 species. Considering the A complement, heterochromatin was located only in the pericentromeric region of pair 1. Staining with chromomycin A3 (CMA3) and labelling with rDNA probe, indicated that this region corresponded to the nucleolus organising region. The B chromosomes of M.quinquefasciata could be found in individuals from different localities, they were completely heterochromatic (C-banding) and uniformly stained by 4’,6-diamidino-2-phenylindole (DAPI). Variations in the number of B chromosomes were detected between cells of the same individual, between individuals of the same colony, and between colonies from different localities.

No abstract

The tropical bush cricket Eneoptera surinamensis (De Geer, 1773) shows a peculiar karyotype with 2n = 9 for males, and 2n = 10 for females, with X1X2Y♂ sex mechanism systems whose origin remains unclear, probably arisen by a two-step chromosome rearrangements, including an X acrocentric and two pair of autosomal acrocentric chromosomes (Mesa & Bran 1964; Ferreira & Cella 2006). This sex system contrasts with the less derived X0♂ found in the majority of the Orthoptera species (White 1973; Hewitt 1979).

RESUMO.-[Descrição histológica do sistema respirató-rio de Cerdocyon thous (Linnaeus, 1766).]A expansão agrícola maciça tornou o Cerdocyon thous, um predador nativo sul-americano, vulnerável. Dados básicos, tais como descrição histológica, são importantes para aumentar o conhecimento sobre as espécies, ajudando nas estratégias de preservação. A eutanásia de animais selvagens para a coleta de amostras não é permitida, por isso os dados sobre a histologia são muito escassos ou inexistentes. O objetivo deste trabalho foi de fornecer uma descrição histológica detalhada da traqueia e árvore brônquica do cachorro do mato Cerdocyon thous (Linnaeus 1766). Os espécimes (um macho e uma fêmea adultos) utilizados foram fornecidos pela Universidade Federal de Pelotas (Pelotas, RS, Brasil), Centro de Reabilitação da Fauna (NURFS). As amostras de tecido foram fixadas em formalina a 10% e incluídas em parafina. Após o corte, as amostras foram coradas com HE (hematoxilina e eosina), PAS (ácido periódico de Schiff) e resorcina fucsina. A traqueia tinha um diâmetro médio de 7,87 milímetros e aproximadamente 57% do diâmetro do epitélio colunar pseudo-estratificado ciliado da mucosa composto por células caliciformes, principalmente na região dorsal do órgão. Os brônquios e bronquíolos apresen- The massive agricultural expansion converted the Cerdocyon thous, a South American native predator, in vulnerable specie. Basic data, such as histological description, are important to raise awareness on animal species, helping on preservation strategies. Considering the difficult in obtain samples, as the euthanasia of wild animals for this purpose is not allowed, data on histology are very scarce or inexistent. The objective of this paper was to provide a detailed histological description of the trachea and bronchial tree of the crab-eating fox Cerdocyon thous (Linnaeus, 1766). The specimens (one adult male and one adult female) used were provided by the Federal University of Pelotas (Pelotas, RS, Brazil) Rehabilitation Center of Wild Fauna (NURFS). Tissue samples were fixed in 10% formalin and included in paraffin. After slicing, samples were stained with HE (hematoxylin and eosin), PAS (periodic acid-Schiff) and resorcin fuchsin. Trachea had an average diameter of 7.87mm, and approximately 57% of the mucosa ciliated pseudo-stratified columnar epithelium was composed of goblet cells, mostly in the dorsal region. Bronchia and bronchioles had a mucosal fold with higher number of goblet cells. Using all these techniques there is no great remarkable differences from C. thous trachea and lung, when compared with the previous described structures for carnivores and most mammals, except for the goblet cells "regionalization". Described results are important to understand the animal physiological and behavioral habits, allowing the development of preservation and protection strategies.INDEX TERMS: Cerdocyon thous, respiratory system, crab-eating fox, wild canids, histology, trachea, bronchial tree, graxaim. taram cararísticas similares aos outros a...