Genetic diversity of fungi occurring in nests of three Acromyrmex leaf-cutting ant species from Córdoba, Argentina.

It is assumed in current literature that the fungus garden cultivated by leaf-cutting ants consists of a single fungus species, the putative mutualistic fungus. However, most studies report a very high rate of fungi contamination (fungi isolated from fungus gardens that are considered not to be the mutualistic fungus). In this article, we report a genetic similarity analysis of all fungi (regardless of their mutualistic condition) isolated from 16 fungus gardens of three Acromyrmex species in Córdoba, Argentina, using intersimple sequence repeat (ISSR) as genetic markers. We isolated 60 clones, of which the three primers employed yielded 53 loci. The patterns revealed a high interclone polymorphism, with a few bands shared by the clones. Of all possible pairwise comparisons, 99% showed a genetic similarity (S) lower than 0.5, the threshold level assumed for fungus Operational Taxonomy Unit (OTU). We found more than one fungus OTU in all studied nests (range 2-11). Cumulative number of OTUs increased linearly with the number of nests sampled. The number of fungus OTUs common to both ant species and sites was very small. We did not find a core group composed of few very common OTUs, as expected if a set of truly mutualistic OTU was present. A simple explanation for the high number of OTUs found is that they are regular components of the fungus garden, which may be used as food source by the ants.

Diet of Eared Doves (Zenaida auriculata, Aves, Columbidae) in a sugar-cane colony in South-eastern Brazil

Farmers in the Paranapanema Valley (Sä¯áPaulo, Brazil) have reported problems with flocks of Eared Doves (Zenaida auriculata) eating sprouting soybeans. In this region these birds breed colonially in sugar-cane, and eat four crop seeds, using 70 percent of the dry weight, in the following order of importance: maize, wheat, rice, and soybeans. Three weeds (Euphorbia heterophylla, Brachiaria plantaginea, and Commelina benghalensis) were important. This information suggests that the doves adapted particularly well to the landscape created by the agricultural practices in the region, exploiting many available foods

Diet of eared doves (Zenaida auriculata, Aves, Columbidae) in a sugar-cane colony in South-eastern Brazil.

Farmers in the Paranapanema Valley (São Paulo, Brazil) have reported problems with flocks of Eared Doves (Zenaida auriculata) eating sprouting soybeans. In this region these birds breed colonially in sugar-cane, and eat four crop seeds, using 70% of the dry weight, in the following order of importance: maize, wheat, rice, and soybeans. Three weeds (Euphorbia heterophylla, Brachiaria plantaginea, and Commelina benghalensis) were important. This information suggests that the doves adapted particularly well to the landscape created by the agricultural practices in the region, exploiting many available foods.

Industrial contributions to desertification in South America.

Degradation of tropical lands has a grim inevitability. This is true of semi-arid and seasonal ecosystems as it is of the rainforests, whose plight has been the principal focus of attention in recent years. The broad belt of savanna-like vegetation in central South America has suffered an accelerating decline in productivity due to overclearing and overgrazing, a process that can be traced directly to the industrialization of Europe in the 19th century. The remorseless slide towards unproductivity need not be slow: a mere 50-100 years seems more than adequate, even for the more robust landscapes. With careful management however, some of these lands are slowly recovering.