Macronutrient balancing affects patch departure by guerezas (Colobus guereza).

Foraging strategies are central in shaping social structure and grouping patterns in primates. We address Colobus guereza foraging strategies by investigating their patch departure decisions in relation to diet composition and nutrition. We examine whether guerezas are constrained in their intake of food in patches and thereby forage according to a fixed amount strategy that dictates patch departure. Additionally, we assess whether guereza employ a fixed time strategy or attempt to balance nutrients when foraging. We measured food patch occupancy time, intake rates, and analyzed foods for macronutrients, fiber, and condensed tannins. We determined that guerezas do not employ a fixed time foraging strategy; patch residence time varied widely between 1 and 290 min. They also did not depart patches or stop eating when they reached a specific intake of dry mass, macronutrients, or condensed tannins. However, guerezas maintained a macronutrient balance when feeding across patches, and the balance of protein to non-protein energy (fats and carbohydrates) in patches is the best indicator of time adult guerezas spent feeding in patches. Previous studies have shown that the protein-to-fiber ratio is important in predicting food selection for folivores and their biomass; however, we found that guerezas did not maximize protein and minimize fiber intake while foraging in patches, nor did they stay longer in patches with the highest ratio of protein to fiber concentrations. This study raises questions about the nutritional and social implications of patch depletion as a foraging strategy in folivorous monkeys where food limitation predicts competitive and social regimes. Am. J. Primatol. 79:e22495, 2017. © 2015 Wiley Periodicals, Inc.

The good and the bad: alkaloid screening and brineshrimp bioassays of aqueous extracts of 31 medicinal plants of eastern Nicaragua.

CONTEXT: Presence/absence tests for alkaloids of 31 medicinal vascular plant species from 31 genera and 26 families of eastern Nicaragua provided a baseline for bioactivity tests. OBJECTIVE: To determine the bioactivity and cytoxicity of aqueous extracts of widely used medicinal species in eastern Nicaragua. MATERIALS AND METHODS: Ethnomedicinal applications were obtained from interviews of traditional healers. We used Dragendorff's reagent to test alkaloids and brine shrimp for cytotoxicity of aqueous extracts. RESULTS: Twenty-nine of the 31 species tested positive for alkaloids. The median lethal concentration that kills 50% of the larvae within 24 h of contact with the extract (LC(50) was less than 1000 µg/mL for 4 (13%) species (the usual cytotoxic category), 1001-5000 µg/mL for 23 (74%) species, and between 5001-7500 µg/mL for the remaining 4 (13%) species. DISCUSSION AND CONCLUSION: Twenty-five of the ethnomedicines contain alkaloids but are not cytotoxic. In contrast to first suppositions, we suggest that this is a good and desirable, and perhaps expected, outcome. Medicinal plants that are cytotoxic may obviously control or kill bacteria or other pathogens, but may also negatively affect the patient; some high alkaloid levels have been associated with carcinogens. Thus, perhaps the majority of effective medicinals should be expected to be noncytotoxic. We suggest that this is a new paradigm for consideration of the overall value and effectiveness of medicinals. Of course, medicinals also can be effective in numerous ways (e.g., organ stimulation or other physiological functions) other than simply as antimicrobials or antipathogens.

Alkaloid presence and brine shrimp (Artemia salina) bioassay of medicinal species of eastern Nicaragua.

We used an alkaloid test and a brine shrimp bioassay to assess the bioactivity of the medicinal plants used by eastern Nicaraguan healers in traditional medicine. Ethnomedicinal uses were obtained from interviews of traditional healers. Aqueous extracts derived from 30 species of angiosperms were assayed for the presence of alkaloids and toxicity. Species tested are distributed in 30 genera and 21 families. Of the 30 species tested for alkaloids with Dragendorff's reagent, 29 contained alkaloids. Toxicological analysis was conducted using the brine shrimp lethal assay (BSLA). Biological activity using BSLA was recorded as the median lethal concentration (LC50) that kills 50% of the larvae within 24 h of contact with the aqueous plant extracts. The LC50 of the shrimp was less than 2500 microg/mL for 3 (10%) species, 2500-5000 microg/mL for 9 (30%), 5001-7500 microg/mL for 7 (23%), 7501-10000 microg/mL for 3 (10%), and greater than 10000 microg/mL for 8 (27%) of the species. The members of the orders Santales and Rubiales in general contained species with greater toxicity than any other group. Struthanthus cassythoides (Struthanthus cassythoides Millsp.(Loranthaceae)). (LC50 1574 microg/mL) and Alibertia edulis (Rich.) A. Rich. (Rubiaceae) (LC50 1741 microg/mL) were the most toxic.

30 days in the life: daily nutrient balancing in a wild chacma baboon.

For most animals, the ability to regulate intake of specific nutrients is vital to fitness. Recent studies have demonstrated nutrient regulation in nonhuman primates over periods of one observation day, though studies of humans indicate that such regulation extends to longer time frames. Little is known about longer-term regulation in nonhuman primates, however, due to the challenges of multiple-day focal follows. Here we present the first detailed study of nutrient intake across multiple days in a wild nonhuman primate. We conducted 30 consecutive all day follows on one female chacma baboon (Papio hamadryas ursinus) in the Cape Peninsula of South Africa. We documented dietary composition, compared the nutritional contribution of natural and human-derived foods to the diet, and quantified nutrient intake using the geometric framework of nutrition. Our focus on a single subject over consecutive days allowed us to examine daily dietary regulation within an individual over time. While the amounts varied daily, our subject maintained a strikingly consistent balance of protein to non-protein (fat and carbohydrate) energy across the month. Human-derived foods, while contributing a minority of the diet, were higher in fat and lower in fiber than naturally-derived foods. Our results demonstrate nutrient regulation on a daily basis in our subject, and demonstrate that she was able to maintain a diet with a constant proportional protein content despite wide variation in the composition of component foods. From a methodological perspective, the results of this study suggest that nutrient intake is best estimated over at least an entire day, with longer-term regulatory patterns (e.g., during development and reproduction) possibly requiring even longer sampling. From a management and conservation perspective, it is notable that nearly half the subject's daily energy intake derived from exotic foods, including those currently being eradicated from the study area for replacement by indigenous vegetation.

Patch depletion behavior differs between sympatric folivorous primates.

Food competition in group-living animals is commonly accepted as a critical determinant of foraging strategies and social organization. Here we examine food patch depletion behavior in a leaf-eating (folivorous) primate, the guereza (Colobus guereza). Snaith and Chapman (2005) studied the sympatric folivorous red colobus (Procolobus rufomitratus), which shares many food resources with the guereza. They determined that red colobus deplete the patches (feeding trees) they use, while we found contrary evidence for guerezas using the same methods. We found that the time guerezas spent feeding in a patch was affected by neither tree size, an indicator of food abundance, nor the size of the feeding group, an indicator of feeding competition. For their principal food item (young leaves), intake rate remained constant and coincided with a decrease in the distance moved to find food within a patch, implying that guerezas do not deplete patches. This points to a fundamental difference in the use of food by guerezas and red colobus, which may be linked to the large difference in their group sizes and/or to a disparity in their digestive physiologies. However, further analyses revealed that the number of feeders within a patch did not affect patch depletion patterns in either species, leaving the potential for a physiological basis as the most plausible explanation. Our research highlights the need for a more critical examination of folivorous primate feeding ecology and social behavior, as all folivorous primates are typically lumped into a single category in socioecological models, which may account for conflicting evidence in the literature.