Assessing the influence of biotic, abiotic, and social factors on the physiological stress of a large Neotropical primate in Atlantic forest fragments.

Wildlife physiological responses to environmental and human-related stressors provide useful clues on animal welfare. Non-invasive biomarkers, such as fecal glucocorticoid metabolites (fGCM), allow researchers to assess whether variations in habitat quality, behavior, and climate influence the animals' physiological stress. We examined the role of fragment size, ambient temperature, ripe fruit availability and consumption, percentage of records moving, sex, female reproductive state, and group composition as predictors of the level of fGCM in adult brown howler monkeys (Alouatta guariba clamitans) inhabiting three small (<10 ha) and three large (>90 ha) Atlantic Forest fragments in southern Brazil. We collected bimonthly behavioral data and fecal samples from adult individuals over three years, and used a multimodel inference framework to identify the main predictors of fGCM. We found that the mean (±SD) fGCM in the study groups ranged from 57 ±â€¯49 ng/g to 93 ±â€¯58 ng/g, which were within the known range for howler monkeys. We found 10 best models including five of the 17 tested variables. Sex and reproductive state were the only variables included in all these models. We found that fGCM was higher in nursing females (mean ±â€¯SD = 104 ±â€¯73 ng/g) than in non-nursing females (64 ±â€¯55 ng/g) and males (53 ±â€¯40 ng/g, P < 0.05) and that it decreased with increasing ripe fruit consumption and minimum temperature. However, fragment size did not predict fGCM concentration (groups in small fragments = 71 ±â€¯58 ng/g vs. groups in large fragments = 63 ±â€¯54 ng/g, P > 0.05). We conclude that factors related to the energetic balance of individuals play major roles in modulating the physiological stress of brown howler monkeys. Future studies should investigate the consequences of higher levels of stress hormones on howler monkey health and demography.

Effect of Roundup® (glyphosate formulation) in the energy metabolism and reproductive traits of Hyalella castroi (Crustacea, Amphipoda, Dogielinotidae).

Roundup(®) (glyphosate formulation) is a nonselective and posts emergent herbicide used for controlling aquatic weeds and different concentrations are used in cultures around the world. The objective of this investigation was to examine the effects of Roundup(®) (glyphosate formulation) on the biochemical composition, levels of lipoperoxidation, Na(+)/K(+)ATPase activity and reproductive traits in the Hyalella castroi. Amphipods were collected in summer 2009, in the southern Brazilian highlands. In the laboratory, the animals were kept in aquariums under controlled conditions for 7 days, and after this period they were exposed to 0.36, 0.52, 1.08 and 2.16 mg/l of glyphosate for 7 days. After the period of exposure, the animals were immediately frozen for determination of glycogen, proteins, lipids, triglycerides, cholesterol, levels of lipoperoxidation, and Na(+)/K(+)ATPase activity. During each day of the cultivation reproductive traits (number of reproductive pairs, ovigerous females and eggs in the marsupium) were observed. All concentrations of Roundup(®) induced significant decreases in all biochemical parameters and Na(+)/K(+)ATPase activity, and significant increase in lipoperoxidation levels. Showing this form a potentially toxic effect at very low concentrations, this pattern of results can lead to significant changes in trophic structure of limnic environments because these amphipods are important links in food chain in these habitats.

Carbofuran-induced alterations in biochemical composition, lipoperoxidation, and Na+/K+ATPase activity of Hyalella pleoacuta and Hyalella curvispina in bioassays.

The present study investigated the effects of carbofuran on the energy metabolism (levels of glycogen, total proteins, total lipids, triglycerides, and lipoperoxidation), Na+/K+ATPase activity, and reproductive parameters (formation of couples, ovigerous females, and mean number of eggs) in the freshwater amphipods Hyalella pleoacuta and Hyalella curvispina. These crustaceans live in limnetic environments of the plateau (H. pleoacuta) and coastal plain (H. curvispina) of the state of Rio Grande do Sul in southern Brazil. The animals were collected in the winter of 2006 in the Vale das Trutas (28 degrees 47'00''S-49 degrees 50'53''W) in the Municipality of São José dos Ausentes, and in Gentil Lagoon (29 degrees 56'30''S, 50 degrees 07'50''W) in the Municipality of Tramandaí. In the laboratory, the amphipods were kept submerged in aquariums under controlled conditions of photoperiod (12 h light: 12 h dark), temperature (23 degrees C+/-1), and constant oxygenation. Animals were exposed to carbofuran at a dose of 5 or 50 microg/L for a period of 7 days. At the end of this period, the animals were immediately frozen for determination of the biochemical parameters, lipoperoxidation levels (TBARS), and enzyme Na+/K+ATPase activity. During each day of culture, several reproductive parameters were observed. Statistical analysis (ANOVA) revealed that carbofuran induces significant decreases in glycogen, proteins, lipids, triglycerides, and Na+/K+ATPase, as well as a significant increase in lipoperoxidation levels. Studies of all the biochemical parameters seem to be quite promising, in order to assess and predict the effects of toxicants on non-target organisms. The results also suggest that the reproductive parameters (formation of couples, ovigerous females and mean number of eggs) may provide sensitive criteria for assessing ecotoxicological effects. Furthermore, H. pleoacuta and H. curvispina are suitable organisms for use in toxicity tests, and we suggest that they are sensitive species that could be used in monitoring studies.