Diet composition of chimpanzees inhabiting the montane forest of Kahuzi,Democratic Republic of Congo

The diet of chimpanzees was investigated by direct observations, feeding remains, and fecal analysis from January 1994 to December 2000 in the montane forest of Kahuzi-Biega National Park. A total of 171 food items were identified, among which 156 items were plant materials belonging to 114 species from 57 taxonomic families. Chimpanzees consumed 66 species of fruits (62 species of pulps and four species of seeds). Results of fecal analysis showed that fig fruits were the most frequently eaten. Their seeds occurred in 92% of a total of 7212 chimpanzee fecal samples. The chimpanzees changed their diet according to seasonal and annual variations in both abundance and diversity of fruit species. However, they are very selective frugivores. Only a few pulp-fruit species are regularly identified in their fecal samples. During the rainy season, when ripe fruit was scarce, chimpanzees relied heavily on piths and leaves. They swallowed leaves of two species of Commelinaceae without chewing, probably for medical purposes. Animal foods were eaten infrequently. The montane forest of Kahuzi, where chimpanzees range up to 2600 m above sea level, may be the highest altitudinal limit ever recorded for their distribution. Compared to other chimpanzee habitats, Kahuzi has a low diversity of fruit species and the availability of a few pulp-fruit species may be critical to the survival of Kahuzi chimpanzees.     

Effect of defoliation on concentrations of allelochemicals and soluble sugars in leaves of weeping birch (<Emphasis Type="Italic">Betula pendula</Emphasis> roth)

Effect of strong (75%) and complete (100%) artificial defoliation of weeping birch Betula pendula Roth on the dynamics of soluble sugars and phenols—flavonols, catechins, and tannins in leaves of damaged plants was investigated. Within the first 15 days after strong defoliation of birch, no changes were found in leaf contents of flavonol, catechin, and tannin. The concentration of sugars first increased but, on the 10th day after defoliation, it returned to the normal level. One year after strong defoliation, the lead concentrations of catechins and tannins in damaged trees increased, while the concentrations of flavonols and sugars did not differ from that in leaves of control trees. In two years after strong damage, the increased concentration of tannins was retained, while catechins and sugars remained at the control level. One year after complete (100%) artificial defoliation, the leaf concentrations of flavonols and sugars in damaged plants did not differ from that in control plants, while the leaf concentrations of catechins and tannins exceeded those in control plants. Two years after complete damage, the leaves contained an increased amount of tannins, whereas the amounts of catechins, flavonols, and sugars did not differ from the control levels.     

Physical and chemical properties of fruit and seeds eaten byPithecia andChiropotes in Surinam and Venezuela

Pithecia pithecia andChiropotes satanas are seed predators that eat fruits with hard pericarps. We measured resistance to puncturing and crushing of fruit and seeds eaten by these two pitheciins at two localities: in evergreen rain forest at Raleighvallen-Voltzberg, Surinam, and in tropical dry/transitional moist forest on islands in Guri Lake, Venezuela. Average measurements of pericarp hardness were similar at both sites for fruit eaten byChiropotes, but a higher maximum value was obtained at the rainforest site.Chiropotes andPithecia both ate fruits that had harder pericarps than did fruits eaten byAteles paniscus, but crushing resistances of seeds eaten were lower than values forAteles. Thus, both pitheciins selected fruits with hard pericarps and soft seeds, although there were notable intergeneric differences in hardness of fruit ingested. When fruit became scarce,Pithecia ate more flowers, whileChiropotes continued to eat fruits with hard seed coverings. Chemical analysis of species of seeds eaten byPithecia suggests that they avoided seeds with extremely high tannin levels, though they tolerated moderate tannin levels in combination with high levels of lipids. We propose that sclerocarpic harvesting (the preparation and ingestion of fruit with a hard pericarp) allows pitheciin monkeys to obtain nutritious seeds, with reduced tannins, that are softer than those ingested by other frugivores.Presented at XIIIth Congress, International Primatological Society, July 27, 1990.     

Hydrolyzable tannins as “quantitative defenses”: Limited impact against Lymantria dispar caterpillars on hybrid poplar

The high levels of tannins in many tree leaves are believed to cause decreased insect performance, but few controlled studies have been done. This study tested the hypothesis that higher foliar tannin levels produce higher concentrations of semiquinone radicals (from tannin oxidation) in caterpillar midguts, and that elevated levels of radicals are associated with increased oxidative stress in midgut tissues and decreased larval performance. The tannin-free leaves of hybrid poplar (Populus tremula × P. alba) were treated with hydrolyzable tannins, producing concentrations of 0%, 7.5% or 15% dry weight, and fed to Lymantria dispar caterpillars. As expected, larvae that ingested control leaves contained no measurable semiquinone radicals in the midgut, those that ingested 7.5% hydrolyzable tannin contained low levels of semiquinone radicals, and those that ingested 15% tannin contained greatly increased levels of semiquinone radicals. Ingested hydrolyzable tannins were also partially hydrolyzed in the midgut. However, increased levels of semiquinone radicals in the midgut were not associated with oxidative stress in midgut tissues. Instead, it appears that tannin consumption was associated with increased metabolic costs, as measured by the decreased efficiency of conversion of digested matter to body mass (ECD). Decreased ECD, in turn, decreased the overall efficiency of conversion of ingested matter to body mass (ECI). Contrary to our hypothesis, L. dispar larvae were able to maintain similar growth rates across all tannin treatment levels, in part, because of compensatory feeding. We conclude that hydrolyzable tannins act as “quantitative defenses” in the sense that high levels appear to be necessary to increase levels of semiquinone radicals in the midguts of caterpillars. However, these putative resistance factors are not sufficient to decrease the performance of tannin-tolerant caterpillars such as L. dispar.     

Selection for nutrients by red deer hinds feeding on a mixed forest edge

We studied the nutritional behaviour of hinds foraging on a mixed-forest edge by direct observation of their choices at each season and by measuring nutrient concentration in the plants. We compared nutrient concentrations in the observed diets with those in the total available vegetation, and with those of 1,000 randomly simulated diets in which we included only those plants that were actually eaten by the animal. Whether the available or the consumed feeds were used as the basis for comparisons had important consequences due to the presence of conifers and ferns, which were high in soluble sugars but were never eaten by the animals (potentially due to their toxicity). The selected diets were lower in sugars than the total available vegetation in summer, but were actually higher in sugars than the random diets generated from consumed forage species only. Hind diets contained more soluble sugars but not more protein than simulated diets in all seasons. Contrary to our prediction, anti-nutritional compounds (ADL and tannins) were avoided only in winter. Compared to simulated diets, hinds consumed more tannins in spring and summer and more ADL in summer and autumn. We suggest that this was a consequence of selection for soluble sugars, because the preferred plant species, which had high soluble sugar concentrations, also contained a large proportion of the anti-nutritional compounds eaten. In winter, the grass-dominated diets contained more fibre (NDF) and less ADL than the simulated diets, indicating that hinds orient their feeding towards digestible fibres. The switch from a browser to a grazer diet was related to a change in the availability of the nutrients, mainly soluble sugars. In our study, grasses contained more soluble sugars and proteins than deciduous browse during winter. This calls into question the dichotomy usually assumed in the literature between grass and browse in terms of nutrient content. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Diet and seasonal changes in sympatric gorillas and chimpanzees at Kahuzi–Biega National Park

Based on 8 years of observations of a group of western lowland gorillas (Gorilla beringei graueri) and a unit-group of chimpanzees (Pan troglodytes schweinfurthii) living sympatrically in the montane forest at Kahuzi–Biega National Park, we compared their diet and analyzed dietary overlap between them in relation to fruit phenology. Data on fruit consumption were collected mainly from fecal samples, and phenology of preferred ape fruits was estimated by monitoring. Totals of 231 plant foods (116 species) and 137 plant foods (104 species) were recorded for gorillas and chimpanzees, respectively. Among these, 38% of gorilla foods and 64% of chimpanzee foods were eaten by both apes. Fruits accounted for the largest overlap between them (77% for gorillas and 59% for chimpanzees). Gorillas consumed more species of vegetative foods (especially bark) exclusively whereas chimpanzees consumed more species of fruits and animal foods exclusively. Although the number of fruit species available in the montane forest of Kahuzi is much lower than that in lowland forest, the number of fruit species per chimpanzee fecal sample (average 2.7 species) was similar to that for chimpanzees in the lowland habitats. By contrast, the number of fruit species per gorilla fecal sample (average 0.8 species) was much lower than that for gorillas in the lowland habitats. Fruit consumption by both apes tended to increase during the dry season when ripe fruits were more abundant in their habitat. However, the number of fruit species consumed by chimpanzees did not change according to ripe fruit abundance. The species differences in fruit consumption may be attributed to the wide ranging of gorillas and repeated usage of a small range by chimpanzees and/or to avoidance of inter-specific contact by chimpanzees. The different staple foods (leaves and bark for gorillas and fig fruits for chimpanzees) characterize the dietary divergence between them in the montane forest of Kahuzi, where fruit is usually scarce. Gorillas rarely fed on insects, but chimpanzees occasionally fed on bees with honey, which possibly compensate for fruit scarcity. A comparison of dietary overlap between gorillas and chimpanzees across habitats suggests that sympatry may not influence dietary overlap in fruit consumed but may stimulate behavioral divergence to reduce feeding competition between them.     

The challenge of interpreting primate diets: mangabey foraging on Blighia unijugata fruit in relation to changing nutrient content

Primates often make foraging selections that are not apparent. For example, they may eagerly consume a particular plant part and species in some instances, but reject it at other times. Blighia unijugata (Baker) fruit is one of the most frequently eaten foods of mangabeys (Lophocebus albigena) in Lwamunda Forest Reserve, Uganda; however, its use varies strikingly depending on the fruit's developmental stage. We conducted feeding observations to investigate the nutritional criteria that mangabeys may have used for the consumption of specific fruit parts by conducting analysis of fruit parts eaten and rejected at different developmental stages. When seeds had low condensed tannins, mangabeys ate them, but seeds were rejected when tannin levels increased. In the first five stages of fruit development, tannin levels in arils declined and the frequency of consumption of the aril increased. Although fat content in seeds increased with maturity, it did not appear to influence seed consumption, but fat content was related to frequency of consumption of the aril. Considering that primates are often making food selections among many species/part combinations, our results illustrate the value of using nutritional analyses to understand foraging decisions. Furthermore, they demonstrate how very specific trade‐offs between consumption of critical nutrients and antifeedants can drive which foods and parts are eaten.     

The condensed tannins (proanthocyanidins) in seagrasses

In a survey of 29 species in the 12 seagrass genera, those in the Potamogetonaceae that characteristically have tannin cells in the leaves (Posidonioideae: Posidonia; Cymodoceoideae: Halodule, Syringodium, Cymodocea, Thalassodendron, Amphibolis) contained compounds with the R_f values and color reactions typical of condensed tannins. Species in the Potamogetonaceae that are not characterized by tannin cells in the leaves (Zosteroideae: Zostera, Phyllospadix, Heterozostera) contained compounds with the R_f values associated with condensed tannins but without the typical staining reactions. Two of the three genera in the Hydrocharitaceae (Enhalus, Thalassia) are characterized by tannin cells in the leaves and contain compounds with the R_f values of condensed tannins but only some of the typical staining reactions. The third genus, Halophila, lacks tannin cells in the leaves and contains compounds with the R_f values of condensed tannins without the typical staining reactions. The role of condensed tannins as feeding deterrents because of their protein-binding properties has been well established for many land plants, but their role in seagrass biology has not been assessed fully.     

Phenology of figs in Budongo Forest Uganda and its importance for the chimpanzee diet

This paper reports on the phenological patterns of figs in Budongo Forest, Uganda, and how it relates to chimpanzee food availability in different seasons. In addition, we analysed the dung of chimpanzees to understand the composition of fruits in their diet. The aim of our study was to assess Ficus phenology and how it affects chimpanzee diet. Fifteen species of figs were monitored for fruit (syconium) and leaf phenology between June 2000 and 2001. Ficus fruit production varied significantly between and within species, and also with tree trunk and crown diameters. Fig fruit production was asynchronous and individual fig trees produced crops from one to five times in a year. In addition to fruits, chimpanzees fed on young leaves of some Ficus species. Shedding of old Ficus leaves coincided with the dry season, followed by appearance of young leaves. The dry season in Budongo is a period of general fruit scarcity. The combination of fig fruits and young leaves make up the most important food in the diet of chimpanzees. From the chimpanzee dung, more than 78% of seeds comprised fig ‘seeds’ (nutlets) and the rest of the diaspores were from other tree species. Our findings suggest that chimpanzees disperse large number of diaspores in their dung, thereby serving as important agents of natural forest regeneration.     

Nutritional Characteristics of Wild and Cultivated Foods for Chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>) in Agricultural Landscapes

Primate habitats are being transformed by human activities such as agriculture. Many wild primates include cultivated foods (crops) in their diets, calling for an improved understanding of the costs and benefits of crop feeding. We measured the macronutrient and antifeedant content of 44 wild and 21 crop foods eaten by chimpanzees (Pan troglodytes schweinfurthii) in a mosaic habitat at Bulindi, Uganda, to evaluate the common assertion that crops offer high nutritional returns compared to wild forage for primates. In addition, we analyzed 13 crops not eaten at Bulindi but that are consumed by chimpanzees elsewhere to assess whether nutritional aspects explain why chimpanzees in Bulindi ignored them. Our analysis of their wild plant diet (fruit, leaves, and pith) corresponds with previous chemical analyses of primate plant foods. Compared to wild food equivalents, crops eaten by the chimpanzees contained higher levels of digestible carbohydrates (mainly sugars) coupled with lower amounts of insoluble fiber and antifeedants. Cultivated fruits were relatively nutritious throughout the ripening process. Our data support the assumption that eating cultivated foods confers energetic advantages for primates, although crops in our sample were low in protein and lipids compared to some wild foods. We found little evidence that crops ignored by the chimpanzees were less nutritious than those that they did eat. Nonnutritional factors, e.g., similarity to wild foods, probably also influence crop selection. Whether cultivated habitats can support threatened but flexible primates such as chimpanzees in the long term hinges on local people’s willingness to share their landscape and resources with them.     

Gorilla diet in the Lopé Reserve,Gabon:

Summary The results of an analysis of gorilla diet in the Lopé Reserve, Gabon are presented. Samples were assayed for nutrients and plant secondary compounds (total phenols, condensed tannins and alkaloids) in an attempt to explain gorilla food choice. The diet is the most diverse so far analysed for gorillas; it seems to be a balance between sugary fruit, proteinaceous leaves, and relatively fibrous stems. Most fruits and herbaceous stems are succulent, but some drier, fibrous fruit and bark is also consumed. Seeds are another component of the diet, including unripe ones. Fruit, seeds, leaves and bark may all contain very high levels of total phenols and condensed tannins; but all herbaceous stems assayed contain low levels of these compounds. Alkaloids are not apparently a significant component of gorilla foods, and may be avoided. Gorillas at Lopé tend to avoid fatty fruit, and select leaves which are high in protein and low in fibre compared to the general vegetation. When fruit and preferred young leaves are scarce, proteinaceous barks and mature leaves, and sugary pith, are important sources of nutrients. We conclude that gorillas exploit the broad frugivore niche in West African lowland forests, and are part of the frugivore community there. What distinguishes them is their ability to eat large fibrous fruit, mature leaves and stems, and to overcome high levels of phenolics (we use phenolics as an umbrella term for both total phenols and condensed tannins). Gorilla diet at Lopé overlaps greatly with that of sympatric, frugivorous, primates, and resembles more closely that of chimpanzees than it does gorilla diet studied elsewhere in Africa.     

Tree resistance to Lymantria dispar caterpillars: importance and limitations of foliar tannin composition

The ability of foliar tannins to increase plant resistance to herbivores is potentially determined by the composition of the tannins; hydrolyzable tannins are much more active as prooxidants in the guts of caterpillars than are condensed tannins. By manipulating the tannin compositions of two contrasting tree species, this work examined: (1) whether increased levels of hydrolyzable tannins increase the resistance of red oak (Quercus rubra L.), a tree with low resistance that produces mainly condensed tannins, and (2) whether increased levels of condensed tannins decrease the resistance of sugar maple (Acer saccharum Marsh.), a tree with relatively high resistance that produces high levels of hydrolyzable tannins. As expected, when Lymantria dispar L. caterpillars ingested oak leaves coated with hydrolyzable tannins, levels of hydrolyzable tannin oxidation increased in their midgut contents. However, increased tannin oxidation had no significant impact on oxidative stress in the surrounding midgut tissues. Although growth efficiencies were decreased by hydrolyzable tannins, growth rates remained unchanged, suggesting that additional hydrolyzable tannins are not sufficient to increase the resistance of oak. In larvae on condensed tannin-coated maple, no antioxidant effects were observed in the midgut, and levels of tannin oxidation remained high. Consequently, neither oxidative stress in midgut tissues nor larval performance were significantly affected by high levels of condensed tannins. Post hoc comparisons of physiological mechanisms related to tree resistance revealed that maple produced not only higher levels of oxidative stress in the midgut lumen and midgut tissues of L. dispar, but also decreased protein utilization efficiency compared with oak. Our results suggest that high levels of hydrolyzable tannins are important for producing oxidative stress, but increased tree resistance to caterpillars may require additional factors, such as those that produce nutritional stress.     

Influence of Plant and Soil Chemistry on Food Selection,Ranging Patterns,and Biomass of <Emphasis Type="Italic">Colobus guereza</Emphasis> in Kakamega Forest,Kenya

Nutritional factors are among the most important influences on primate food choice. We examined the influence of macronutrients, minerals, and secondary compounds on leaf choices by members of a foli-frugivorous population of eastern black-and-white colobus—or guerezas (Colobus guereza)—inhabiting the Kakamega Forest, Kenya. Macronutrients exerted a complex influence on guereza leaf choice at Kakamega. At a broad level, protein content was the primary factor determining whether or not guerezas consumed specific leaf items, with eaten leaves at or above a protein threshold of ca. 14% dry matter. However, a finer grade analysis considering the selection ratios of only items eaten revealed that fiber played a much greater role than protein in influencing the rates at which different items were eaten relative to their abundance in the forest. Most minerals did not appear to influence leaf choice, though guerezas did exhibit strong selectivity for leaves rich in zinc. Guerezas avoided most leaves high in secondary compounds, though their top food item (Prunus africana mature leaves) contained some of the highest condensed tannin concentrations of any leaves in their diet. Kakamega guerezas periodically traveled great distances to exploit rare foods (bark from exotic Myrtaceae trees and soil) outside their normal home ranges. Our results suggest that these journeys were driven by the fact that these rare foods contained exceptionally high sodium concentrations, a mineral believed to be deficient in the guereza's usual diet. Lastly, our results are consistent with the pattern established across other Paleotropical rain forests in which colobine biomass can be predicted by the protein-to-fiber ratio in mature leaves. Of the 8 rain forests for which the relevant data are available, Kakamega features the second highest mature leaf protein-to-fiber ratio as well as the second highest colobine biomass.     

Tannin concentration enhances seed caching by scatter-hoarding rodents: An experiment using artificial ‘seeds’

Tannins are very common among plant seeds but their effects on the fate of seeds, for example, via mediation of the feeding preferences of scatter-hoarding rodents, are poorly understood. In this study, we created a series of artificial ‘seeds’ that only differed in tannin concentration and the type of tannin, and placed them in a pine forest in the Shangri-La Alpine Botanical Garden, Yunnan Province of China. Two rodent species (Apodemus latronum and A. chevrieri) showed significant preferences for ‘seeds’ with different tannin concentrations. A significantly higher proportion of seeds with low tannin concentration were consumed in situ compared with seeds with a higher tannin concentration. Meanwhile, the tannin concentration was significantly positively correlated with the proportion of seeds cached. The different types of tannin (hydrolysable tannin vs condensed tannin) did not differ significantly in their effect on the proportion of seeds eaten in situ vs seeds cached. Tannin concentrations had no significant effect on the distance that cached seeds were carried, which suggests that rodents may respond to different seed traits in deciding whether or not to cache seeds and how far they will transport seeds.     

围栏条件下同域分布三种鼠对两种种子的贮藏行为差异

种子贮藏是啮齿动物利用食物资源的一种适应性行为。同域分布的啮齿动物可能进化出不同的贮藏方式和策略。为了解同域分布的啮齿动物的贮藏策略及种子特征在动物贮藏行为决策中的作用,于2014年10-12月,通过半自然围栏实验,在秦岭南坡的佛坪国家级自然保护区内调查了同域分布社鼠、中华姬鼠和甘肃仓鼠对板栗和锐齿槲栎种子的贮藏策略差异,并探讨了2种种子特征在鼠类贮藏行为决策中的作用。结果显示：1）社鼠主要集中贮藏板栗种子,未分散贮藏任何种子;中华姬鼠未贮藏板栗种子,对锐齿槲栎种子同时表现出集中和分散贮藏行为,以集中贮藏为主;甘肃仓鼠对2种种子均表现出集中贮藏行为,未表现分散贮藏行为。2）社鼠和甘肃仓鼠均倾向于集中贮藏有较高营养价值（高蛋白和脂肪）且单宁含量较低的板栗种子;中华姬鼠倾向于分散贮藏单宁含量高的锐齿槲栎种子。3）3种鼠均喜好取食有较高营养价值且单宁含量低的板栗种子,很少取食单宁含量高的锐齿槲栎种子。结果表明同域分布鼠类对不同种子的贮藏方式有所不同,种子特征影响鼠类的取食和贮藏策略。     

Tannins from mimosoid legumes of Texas and Mexico

The percentage of tannins in leaves, bark, wood, and immature fruits of several species of Acacia and related mimosoid legumes from the southwestern U.S. and Mexico, along with a few from Costa Rica and Argentina, was determined by a modified hide powder procedure and by precipitation with casein. The relative percentages of hydrolyzable and condensed tannins were determined by the iodate and the vanillin-HCl methods, respectively. Gallotannins of selected samples were also determined by the rhodanine method. Although the amount of total tannins was similar for the first two methods, values for condensed tannins by the vanillin-HCl method were frequently two to four times greater than the total tannin values.     

Bark Consumption by the Painted Ringtail (Pseudochirulus forbesi larvatus) in Papua New Guinea1

We documented bark consumption by painted ringtails (Pseudochirulus forbesi) and other arboreal marsupials at Mt. Stolle, Papua New Guinea. Evidence consisted of scratch marks on the boles of trees in conjunction with the removal of all moss and direct sightings of animals eating bark. Only 43 trees ≥10 cm diameter at breast height (DBH) of 19 species showed signs of consumption at the study site; five of these species were confirmed by direct sighting to be consumed by painted ringtails. We sought to determine if bark of these trees contained important dietary minerals. Analyses showed that calcium and potassium, individually and combined, were significantly more abundant in eaten versus uneaten trees of the same species. On average, eaten trees showed 4.7 and 2.2 times the amount of these minerals, respectively, as found in uneaten trees. Adult males were more likely than adult females or juvenile males to be captured at eaten trees than away from them. Two species of Syzygium and one species of Sloanea were highly selected for bark consumption, but not all trees of a species were eaten; rather, particular individuals of these species were preferred. We conclude that bark appears to be an important source of calcium and potassium, and speculate on the relationship between the limited availability of these special trees and the social behavior of painted ringtails.     

Partitioning of 14C-labeled photosynthate to allelochemicals and primary metabolites in source and sink leaves of aspen: evidence for secondary metabolite turnover

Theories on allelochemical concentrations in plants are often based upon the relative carbon costs and benefits of multiple metabolic fractions. Tests of these theories often rely on measuring metabolite concentrations, but frequently overlook priorities in carbon partitioning. We conducted a pulse-labeling experiment to follow the partitioning of ¹⁴CO₂-labeled photosynthate into ten metabolic pools representing growth and maintenance (amino acids, organic acids, lipids plus pigments, protein, residue), defense (phenolic glycosides, methanol:water and acetone-soluble tannins/phenolics), and transport and storage (sugars and starch) in source and importing sink leaves of quaking aspen (Populus tremuloides). The peak period of ¹⁴C incorporation into sink leaves occurred at 24 h. Within 48 h of labeling, the specific radioactivity (dpm/mg dry leaf weight) of phenolic glycosides declined by over one-third in source and sink leaves. In addition, the specific radioactivity in the tannin/phenolic fraction decreased by 53% and 28% in source and sink leaves, respectively. On a percent recovery basis, sink leaves partitioned 1.7 times as much labeled photosynthate into phenolic glycosides as source leaves at peak ¹⁴C incorporation. In contrast, source leaves partitioned 1.8 times as much ¹⁴C-labeled photosynthate into tannins/phenolics as importing sink leaves. At the end of the 7-day chase period, sink leaves retained 18%, 52%, and 30% of imported ¹⁴C photosynthate, and labeled source leaves retained 15%, 66%, and 19% of in situ photosynthate in metabolic fractions representing transport and storage, growth and maintenance, and defense, respectively. Analyses of the phenolic fractions showed that total phenolics were twice as great and condensed tannins were 1.7 times greater in sink than in source leaves. The concentration of total phenolics and condensed tannins did not change in source and sink leaves during the 7-day chase period. Received: 31 July 1998 / Accepted: 8 February 1999     

Tannins from four commonAcacia species of Texas and Northeastern Mexico

The amount of tannins present inAcacia berlandierii, A. farnesiana, A. greggii andA. rigidula, 4 common species of the southwestern United States and northern Mexico, was determined. Bark samples of the 4 species were extracted with water, 80% methanol, and 70% acetone. Of these, 70% acetone proved to be the most efficient solvent. Tannins were determined by Folin-Denis analysis for total phenolic materials, followed by precipitation with casein or hide powder. The hidepowder method was modified to facilitate handling of smaller samples. Results of tannin determination by casein and hide-powder precipitation methods gave comparable results. The amount of tannins present in leaves, bark, wood, and immature fruits of samples of these species was then determined by the same analytical methods. In most instances, bark and immature fruits had the highest percentage of tannins (5–15%) and wood was much lower (less than 1%). Leaves had intermediate values.     

Nutritional Values of 14 Fig Species and Bat Feeding Preferences in Panama1

Figs are a critical resource for many tropical frugivores, yet they often are referred to as low quality fruits. To determine their nutritional value, both as a group and for individual species, we analyzed 14 fig species from Barro Colorado Island (BCI), Panama, for fiber, tannins, lipids, protein, carbohydrates, amino acids, and minerals. Seeds and pulp were analyzed separately. Fig fruit pulp consisted of about one‐third digestible components, mostly carbohydrates with some lipids and proteins. Tannin, lignin, and water‐soluble carbohydrates showed considerable variation among species, as did fruit size. Figs contained high amounts of amino acids, such as leucine, lysine, valine, and arginine, and minerals, such as potassium, calcium, magnesium, sodium, and phosphorus. One species, Ficus insipida, contained the highest concentrations of almost all amino acids, many minerals, and protein. Small figs had as much nutritional value per gram as large figs. Free‐standing figs had higher percentages of protein, complex carbohydrates, and ash than strangler figs, which had higher percentages of water‐soluble carbohydrates, tannins, and hemicellulose. The guild of fruit‐eating bats on BCI included ten common species with diets dominated by figs. Fecal analyses and captures at ripe fig trees showed a consistent pattern of resource partitioning. Small bats preferentially ate small‐fruited and strangler figs while large bats consumed mostly large‐fruited and free‐standing figs. Small bats most often ate F. bullenei, which has high levels of lipid and carbohydrates, and F. yoponensis, which has high levels of protein. Medium and large bats most often ate F. insipida, a nutritionally superior species; their second most eaten species was F. obtusifolia, in which the large size may make it efficient to eat. Each bat ate a variety of fig species, supporting the idea that although no single species of fig may be sufficient to sustain frugivores, a mix of fig species can provide a complete set of nutrients.