Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

We have found the following differences in the male meiosis among three triatomine species: (1) The three largest autosomal bivalents of Triatoma infestans are heterochromatic. Rhodnius prolixus has two autosoreal bivalents with heterochromatic blocks. Triatoma rubrovaria does not show any heteropycnotic autosomes. (2) Sex chromosomes in T. infestans form a chromocenter. At early prophase terminal associations are seen between sex chromosomes in T. rubrovaria, and they maintain a close association until diakinesis. An intimate association between the X and Y chromosomes is observed during early prophase in R. prolixus, but a distant association is maintained by the sex chromosomes at diffuse and diplotene stages in this species. (3) Polyploid nuclei of the nutritive cells are quite distinct. Numerous chromocenters of different shapes and sized are seen in those of T. infestans. In T. rubrovaria one chromocenter having two positively heteropycnotic elements is observed surrounded by homogeneous chromatin. Only one compact chromocenter is found amongst unevenly distributed chromatin, in R. prolixus.

It has been studied the feeding patterns of Triatoma rubrovaria (wild triatominae bug, and intradomiciliary secondary vector of T. cruzi) in a rural area of "La Bolsa" (Department of Artigas). Agar double diffusion test were used for analyze the blood meal, from 120 insects, which were confronted to 13 antisera. It has 251 identify blood meals, and the most frequently was mammalian host (73%), but it has a variable source of feeding (mammals, birds, reptiles and cockroach), including humans rate 8% of the total. The identify of haemolimphe as feed, place this triatominae bug as an intermediary vector between predator and haematophagous. The most usual mammals are dasypodides and bovines. The frequence of human blood meal near the dwellings, shows its potentiality as vectors. Therefore, the peridomicile is an area of interaction between, domestic, wild and sinantropic host. The trypanosomic infection's rate at peridomiciles was lesser those at wild areas.

Ruminant livestock are important sources of human food and global greenhouse gas emissions. Feed degradation and methane formation by ruminants rely on metabolic interactions between rumen microbes and affect ruminant productivity. Rumen and camelid foregut microbial community composition was determined in 742 samples from 32 animal species and 35 countries, to estimate if this was influenced by diet, host species, or geography. Similar bacteria and archaea dominated in nearly all samples, while protozoal communities were more variable. The dominant bacteria are poorly characterised, but the methanogenic archaea are better known and highly conserved across the world. This universality and limited diversity could make it possible to mitigate methane emissions by developing strategies that target the few dominant methanogens. Differences in microbial community compositions were predominantly attributable to diet, with the host being less influential. There were few strong co-occurrence patterns between microbes, suggesting that major metabolic interactions are non-selective rather than specific.

This paper describes population structure, spatial distribution and habitat selection of wild and peridomestic populations of Triatoma rubrovaria (Blanchard, 1843). Field studies were carried out at Las Piedras and La Bolsa in the Northern Department of Artigas, Uruguay. A semicircular sampling area, divided in seven or eight triangular sectors was sequentially examined from October 1990 to November 1991. At Las Piedras (typical wild habitat) 1063 T. rubrovaria bugs were collected from 84% of the rocky outcroops ("pedregales"). Abundance varied by season peaking in October-November (spring). Throughout the year, most of the population was made up of third, fourth and fifth instar nymphs; adults were found from October to March. In the peridomestic environment of La Bolsa, however T. rubrovaria was less common and showed a more irregular instar distribution. Colonized ecotopes, were those close to houses. In both sites T. rubrovaria was mainly associated with the geckonid Homonota uruguayensis and the cockroach Blaptica dubia.