Monitoring the Diversity of Hunting Ants (Hymenoptera: Formicidae) on a Fragmented and Restored Andean Landscape.

Hunting ants are predators of organisms belonging to different trophic levels. Their presence, abundance, and diversity may reflect the diversity of other ants and contribute to evaluate habitat conditions. Between 2003 and 2005 the restoration of seven corridors in an Andean rural landscape of Colombia was performed. The restoration took place in lands that were formerly either forestry plantations or pasturelands. To evaluate restoration progress, hunting ants were intensely sampled for 7 yr, using sifted leaf litter and mini-Winkler, and pitfall traps in 21 plots classified into five vegetation types: forests, riparian forests, two types of restored corridors, and pasturelands. The ant communities were faithful to their habitat over time, and the main differences in ant composition, abundance, and richness were due to differences among land use types. The forests and riparian forests support 45% of the species in the landscape while the restored corridors contain between 8.3-25%. The change from forest to pasturelands represents a loss of 80% of the species. Ant composition in restored corridors was significantly different than in forests but restored corridors of soil of forestry plantations retained 16.7% more species than restored corridors from pasturelands. Ubiquitous hunting ants, Hypoponera opacior (Forel) and Gnamptogenys ca andina were usually associated with pastures and dominate restored corridors. Other cryptic, small, and specialized hunting ants are not present in the restored corridors. Results suggest that the history of land use is important for the biodiversity of hunting ants but also that corridors have not yet effectively contributed toward conservation goals.

Effect of two agroecological management strategies on ant (Hymenoptera: Formicidae) diversity on coffee plantations in southwestern Colombia.

Simplification of agroecosystems because of industrialization of agriculture may cause the loss of associated animal biodiversity of both vertebrates and invertebrates. To measure how the agricultural intensification on coffee plantations affects ant biodiversity, we intensively sampled ants in Caldono (Cauca, Colombia). We surveyed 15 sites classified into three management types: sun coffee plantations, shaded coffee plantations, and forest patches. Fifteen 50-m linear transects, each one consisting of 5 pitfall traps and 5 tuna baits, were set at each sampling location between December of 2009 and February of 2010. We collected 18,186 ants that represent 82 ant species, 34 genera, and 9 subfamilies of Formicidae (Hymenoptera: Formicidae). The management intensification index showed an increasing intensification gradient along the 15 sampling locations from forest patches to shaded coffee to sun coffee plantations. Shaded coffee plantations harbored the highest number of species (60), followed by forest (56) and sun coffee (33). Ant species composition and plant structure on shaded coffee plantations resembled the forest patches more than the sun coffee plantations. Forest and shaded coffee plantations had a more equitable distribution of ant species, whereas in sun coffee plantations, Linepithema neotropicum (Emery) and Ectatomma ruidum (Roger) typically outnumbered all other ant species. Evidence from functional groups indicated that specific habitat and feeding requirements exist among the species that are found together. Our results confirmed that intensification of agriculture negatively affects ant diversity, despite the fact that farms were located in a heterogeneous landscape, suggesting that agroecological management is a strong determinant in the conservation of wild fauna.

Increased neuronal proliferation in human bacterial meningitis.

OBJECTIVE: Neurogenesis is increased in experimental models of bacterial meningitis. In this study, neurogenesis was examined after bacterial infection of the CNS, and after stroke and brain trauma in humans. METHODS: Brain sections of patients after death from bacterial meningitis, stroke, or brain trauma and from autopsy cases after death from nonneurologic diseases were investigated by immunohistochemistry. RESULTS: In the dentate gyrus, the density of proliferating cellular nuclear antigen-expressing cells was higher after bacterial meningitis compared to the control group (p = 0.0075). Furthermore, the number of cells expressing the immature neuronal marker proteins TUC-4 and doublecortin were increased in brain sections of patients after death from meningitis compared to control cases (p = 0.0067 and p = 0.045). After stroke and brain trauma, higher densities of proliferating cells were observed (p = 0.031 and p = 0.018), while an increase of TUC-4-expressing cells was detected after stroke only (p = 0.0012 and p = 0.47). CONCLUSIONS: The increased proliferation of neural progenitors suggests an endogenous mechanism in response to noxious stimuli. Stimulation of neurogenesis might help to alleviate the consequences of neuronal destruction in bacterial meningitis and other diseases of the brain.