Abstract In South America, Solenopsis saevissima and S. invicta are the most common fire ants. Nests are founded in areas under anthropic interference like urban or rural areas, but S. invicta is found preferentially in those with the greatest anthropic interference. However, we do not know the rates at which they exist in anthropized areas next to high density of native vegetation. Areas with 60 to 90% of native Atlantic Forest were selected to verify the occurrence of both species in rural and urban areas. We investigated the molecular diversity and applied the reconstruction of the ancestral state analysis for each species. A total of 186 nests were analyzed and we found that the two species had the same proportion in the urban area. However, S. saevissima had a higher rate of prevalence in the rural area, in addition to having a greater number of haplotypes and ancestry associated with this type of habitat for the region. S. invicta had the same number of haplotypes in both rural and urban regions, and less haplotypic diversity. We conclude that S. saevissima is a species typically associated with rural areas and S. invicta, although present, is not dominant in urban areas.

Este estudo visou à caracterização das membranas fetais em búfalas (Bubalus bubalis, Linnaeus 1758) no terço inicial da gestação. As membranas fetais foram analisadas macroscópica e microscopicamente (luz e microscopia eletrônica de transmissão). O córion possui uma camada simples de células circulares, com núcleos de forma esférica, denominadas trofobláticas; há outro tipo celular, as células trofoblásticas gigantes, com dois ou mais núcleos. Ambas possuem uma grande quantidade de vesículas no citoplasma e retículo endoplasmático à microscopia de transmissão. O alantóide possui vasos preenchidos com eritrócitos, e contêm células alongadas, que formam um epitélio estratificado simples. O âmnion é uma membrana transparente, ou esbranquiçada; constituído por epitélio estratificado simples. A diferença principal entre o alantóide e o âmnion é que o último é avascular. O saco vitelínico é uma membrana opaca que desaparece durante a gestação; é a única membrana que não está em contato com as outras e apresenta três tipos diferentes de células que dão forma a três camadas distintas (endoderma, mesotélio, mesênquima).

The aim of the study was to characterize the fetal membranes in buffalo cows (Bubalus bubalis, Linnaeus 1758) in the first 3 months of the gestation. The fetal membranes were analyzed gross and microscopically (light and ultrastructural analysis). The corion is a simple layer of circle cells, with spherical nucleus, named trofoblastics; there is another cellular type, named trophoblastic giant cells, with two or more nucleus. Both of them have many cytoplasmic and reticule endoplasmic vesicles on transmission electron microscopy. The allantoic has many vessels filled with eritrocytes, elongated cells which form a stratified simple epithelium. The amnion is transparent or sometimes whitish, consisting of a stratified simple epithelium. The main difference between the allantoic and amnion is that the latter is avascular. The yolk sac is an opaque membrane that disappears during gestation, and is the only membrane that is not in contact with the others; it presents three different types of cells which form three distinct layers (endoderm, mesothelium and mesenquimal).