Benefits of polyspecific associations for the Goeldi's monkey (Callimico goeldii).

Polyspecific associations are an important component of Callimico goeldii behavior and ecology. On average, Callimico goeldii was found in proximity to or in vocal contact with Saguinus troops (S. fuscicollis and S. labiatus) during 53% of all time intervals sampled. Polyspecific associations varied considerably between seasons, however, with association rates peaking during the wet-season month of February (89%) and declining in the dry season, with the lowest rate (13%) in July. The primary benefits of associations appear to be an increased use of the lower and middle canopy, and an increase in feeding behaviors during the wet season. Thus, Callimico goeldii appear to benefit most from associations during the wet season when fruits are its principal food source. Fruits are eaten more in the forest canopy than in the understory; thus, an increase in height use likely permits an increase in the fruit resources on which Callimico goeldii can forage and feed. In addition, Saguinus groups, with their smaller home ranges, are likely to be more knowledgeable than Callimico goeldii about the location and abundance of ripe fruits in their home ranges. Thus, Callimico goeldii may parasitize Saguinus for their fruit knowledge by following them through their ranges. In the dry season, limited dietary overlap between Callimico goeldii and Saguinus groups is likely to make associations less beneficial for Callimico goeldii as they adopt different foraging and ranging strategies.     

Forest use and activity patterns of Callimico goeldii in comparison to two sympatric tamarins, Saguinus fuscicollis and Saguinus labiatus

Callimico goeldii, Saguinus fuscicollis, and S. labiatus are sympatric in northern Bolivia and differ from each other in patterns of spatial and structural use of their environment. C. goeldii has a home range five times larger than that of mixed-species troops of S. fuscicollis and S. labiatus. The larger overlapping home range of C. goeldii allows it to move among Saguinus troops, giving it access to a wide range of different microhabitats. All three species use the most common microhabitat in the area, primary forest with dense understory, more than any other microhabitat type. C. goeldii habitat use varies by season, with bamboo and Heliconia microhabitats used more during the dry season. Each species shows preferences for different height classes: C. goeldii is found almost exclusively in the understory, S. fuscicollis uses the understory and middle canopy, and S. labiatus is found mostly in the middle canopy. These height class preferences are reflected in each species' locomotor styles, with C. goeldii showing the highest rates of vertical clinging and leaping, and S. labiatus showing the highest rates of branch-to-branch leaping and quadrupedal movement. The results suggest that C. goeldii may be restricted to forests with dense understory and a mosaic of other microhabitats. Furthermore, C. goeldii does not appear to use its tegulae for large branch foraging, but rather for vertical clinging and leaping between small vertical supports.     

Patterns of positional behavior in mixed-species troops of Callimico goeldii, Saguinus labiatus, and Saguinus fuscicollis in northwestern Brazil

We present the results of a 4-month field investigation of positional behavior, vertical ranging, and species differences in limb proportions and body mass in a mixed-species troop of Saguinus fuscicollis, Saguinus labiatus, and Callimico goeldii in northwestern Brazil. Despite certain similarities in overall positional repertoire, patterns of positional behavior varied significantly between species. Travel in Callimico occurred principally in the lowest levels of the canopy, and was characterized by an exaggerated form of hindlimb-dominated bounding (bounding-hop), and leaping to and from vertical trunks (55.1% of leaps). In contrast, saddle-back tamarins traveled in the lower and middle levels of the canopy, and engaged in a range of leaping behaviors, including stationary leaps (37.3%), acrobatic leaps (31.3%), and trunk-to-trunk leaps (20%). Red-bellied tamarins exploited the highest levels of the arboreal canopy. Travel in this species was dominated by quadrupedal bounding and acrobatic leaps (67% of leaps) that began and ended on thin, flexible supports. Species differences in positional behavior correlated with species differences in limb proportions and locomotor anatomy, and provide a framework for understanding niche partitioning in mixed-species troops of Saguinus and Callimico.     

Exudates as a fallback food for Callimico goeldii

Fallback foods have been defined as resources for which a species has evolved specific masticatory and digestive adaptations, and are consumed principally when preferred foods are scarce. In the present field investigation, we examine fungi, fruit, and exudate consumption in one group of Callimico goeldii in order to determine the importance of exudates as a fallback food for this species. Based on a total of 1,198 hr of quantitative behavioral data collected between mid-November 2002-August 2003, we found that pod exudates of Parkia velutina accounted for 19% of callimico feeding time in the dry season. This resource was not consumed in the wet season when fruits and fungi were the most common items in the diet. In the dry season of 2005 (July), the same callimico study group did not consume Parkia pod exudates. Instead, the group ate exudates obtained from holes gouged in tree trunks by pygmy marmosets and exudates resulting from natural weathering and insect damage on trunks, roots, and lianas. Pod exudates are reported to contain greater amounts of readily available energy than do trunk and root exudates, and were consumed throughout all periods of the day, particularly in the late afternoon. Trunk and root exudates were consumed principally in the morning. We propose that digestive adaptations of the hindgut, which enable callimicos to exploit fungi (a resource high in structural carbohydrates) year-round, predispose them to efficiently exploit and process exudates as fallback foods when other resources, such as ripe fruits, are scarce.     

Dietary classification of extant kangaroos and their relatives (Marsupialia: Macropodoidea)

Kangaroos and kin (superfamily Macropodoidea) are the principal endemic herbivores of Australia and the most diverse radiation of marsupial herbivores ever to have evolved. As is typical of other herbivore groups (e.g. bovids), dietary niches span fruit, fungi, dicot leaves and monocot grasses in both specialists and generalists, but to date dietary classification has been largely ad hoc and poorly tied to actual dietary ecological data. Here we provide a simple dietary classification of the Macropodoidea based on an extensive literature survey. Intake of four major dietary items – grasses, dicot leaves, fruits and seeds, and fungi – was assessed using proportional intake for 19 species and categorical (ranked intake) data for 37 species. Statistical comparisons with cluster and principal components analyses aligned species into four dietary groups. Members of the first group have diets that primarily consist of fungi and fruits. Relative proportions of grasses to dicot leaves separate the remaining species into browser (more than 70% dicots), grazer (more than 70% grasses) and mixed feeder groups. Comparison of our diet‐based classification with a prevailing scheme based on dental morphology suggests that most species with what has traditionally been viewed as a ‘browser‐grade dentition’ are actually mixed feeders. This suggests that either morphology and diet are not tightly linked or that morphological differences between the dentitions of browsers and mixed feeders are subtle and have been overlooked. A positive correlation was found between body mass and average proportional intake of grass in the diet of macropodoids. This parallels the situation found in bovids, as well as the percentage cut‐off between dietary groups. These trends suggest that some underlying ecophysiological constraints may influence food choice in mammalian herbivores providing useful pointers to the diets of extinct taxa.     

Composition and Nutritional Characteristics of Fungi Consumed by Callimico goeldii in Pando, Bolivia

Though ≥22 species of Primates consume fungi, most do so at low rates, comprising <5% of their feeding time. Goeldi's monkeys (Callimico goeldii), spend up to 29% of their feeding time year-round consuming fungal sporocarps, the fruiting bodies of fungi. We provide comprehensive data on the nutritional characteristics of 4 species of fungi consumed by Callimico goeldii (Ascopolyporus polyporoides, Ascopolyporus polychrous, Auricularia auricula, and Auricularia delicata). The composition of the fungi is similar to that of other fungi: predominantly fiber (66.2–83.0% dry matter) with small amounts of sugar (2.0–5.6% dry matter) and crude fat (0.9–1.6% dry matter). Though the crude protein content is substantial (5.5–13.4% dry matter), much of the nitrogen in the fungi is not likely to be available to Callimico goeldii because it is associated with indigestible food components or is in nonprotein form. The mineral content of the fungi are within the normal range for fungi generally and the calcium-to-phosphorus ratio is low (0.07–0.25). Fungi appear to be a low-quality food resource for Callimico goeldii and may contribute to their relatively large home ranges and low population density compared to other Callitrichinae. Research on the ability of Callimico goeldii to digest fungi is needed to understand fully the nutritional value of fungi to them. We discuss adaptations Callimico goeldii may have for improving their ability to obtain nutrients from fungi and potential ecological correlates of mycophagy.     

Foraging strategies of yakushima macaques(Macaca fuscata yakui)

I investigated the activity budget and diet of Yakushima macaques (Macaca fuscata yakui,)in warm temperate broad- leaved forest of Yakushima, Japan. Both time spent feeding and time spent moving varied considerably between half- months. However, total time spent in active behaviors— feeding time plus moving time— was stable. The composition of the diet also showed considerable variation between half- months. The macaques fed mainly on fruits, seeds,mature leaves, fallen seeds, flowers, and young leaves, each of which accounted for more than 30% of feeding time in at least 1 half- month. They also ate insects and fungi, but each of them comprised ≤ 25 and ≤ 8% of feeding time in any half- month, respectively. Time spent feeding on mature leaves, young leaves, flowers, or fallen seeds is positively correlated with total time feeding and is negatively correlated with time moving. In contrast, time feeding on fruits, seeds, insects or fungi is negatively correlated with time feeding and is positively correlated with time moving. Foraging on foods that have a low energy content, a high density, and a relatively even distribution— mature leaves— or that need much manipulation to be processed— flowers and fallen seeds— increased feeding time, while foraging on foods for which monkeys must search intensively in the forest— fruits, seeds, insects, and fungi— led to increased moving time. I examined foraging strategies of Yakushima macaques in terms of moving costs and the quality of food items. Regarding time feeding on fruits, which have more energy and may need less manipulation than other foods, as a benefit, and moving time as a cost, they seemed to employ a strategy that balanced the costs and benefits of foraging.     

Diet and feeding behavior of Rhinopithecus brelichi at Yangaoping, Guizhou

Expectations of increases in human population growth and accelerated habitat loss, along with the realization that efforts to provide protection for ecosystems that sustain primates have met with limited success, make it critical that conservation plans are grounded firmly in scientific observation. Studies of the diet breadth and feeding behavior of endangered species, therefore, are critical for understanding ecological adaptations and developing a conservation strategy. The diet and feeding ecology of gray snub-nosed monkeys (Rhinopithecus brelichi) were studied in the Fanjingshan National Nature Reserve, Guizhou, China. The monkeys were found to consume 107 different species of trees, shrubs, and ground plants from 58 genera and 28 families. Food items included young leaves, mature leaves, flowers, fruits/seeds, buds, and insects. Among these food items, there were at least 13 evergreen species of tree and liana, 3 species of grasses, and at least 2 kinds of invertebrates collected from decayed wood. Diet varied markedly throughout different seasons. Overall, diet composition (based on feeding records) was 15.3% buds, 25.5% young leaves, 21.8% mature leaves, 9.4% flowers, 21.6% fruits/seeds, and 6.3% other items. The monkeys feed mainly on young leaves and flowers in spring, unripe fruits/seeds and young leaves in summer, ripe fruits/seeds in autumn, and mature leaves and buds in winter. We propose that when inhabiting forests of lower elevation and greater vegetation complexity, R. brelichi is characterized by expanded diet breadth and includes a greater diversity of food types and plant species in its diet. One food type that appears critical to the diet of this species, especially during the winter, are the buds of Magnolia sprengeri. To protect this resource we advocate working with local communities to limit the collection of M. sprengeri, which is used in traditional Chinese medicine and has high economic value for people in the reserve.     

Blood sugar formation due to abnormally elevated gluconeogenesis: aberrant regulation in a parasitized insect, Manduca sexta Linnaeus.

Alterations of carbohydrate metabolism associated with parasitism were examined in an insect, Manduca sexta L. In insect larvae maintained on a low carbohydrate diet gluconeogenesis from [3-13C]alanine was established from the fractional 13C enrichment in trehalose, a disaccharide of glucose and the blood sugar of insects and other invertebrates. After transamination of the isotopically substituted substrate to [3-13C]pyruvate, the latter was carboxylated to oxaloacetate ultimately leading to de novo glucose synthesis and trehalose formation. Trehalose was selectively enriched with 13C at C1 and C6 followed by C2 and C5. 13C enrichment of blood sugar in insects parasitized by Cotesia congregata (Say) was significantly greater than was observed in normal animals. The relative contributions of pyruvate carboxylation and decarboxylation to trehalose labeling were determined from the 13C distribution in glutamine, synthesized as a byproduct of the tricarboxylic acid cycle. The relative contribution of carboxylation was significantly greater in parasitized larvae than in normal insects providing additional evidence of elevated gluconeogenesis due to parasitism. Despite the increased gluconeogenesis in parasitized insects the level of blood sugar was the same in all animals. Because de novo glucose synthesis does not normally maintain blood sugar level in insects maintained under these dietary conditions the findings suggest an aberrant regulation over gluconeogenesis. The 13C labeling in trehalose was nearly symmetric in all insects but the mean C1/C6 13C ratio was higher in parasitized animals suggesting a lower activity of the pentose phosphate pathway that brings about a redistribution of 13C in trehalose following de novo glucose synthesis. Additional studies with insects maintained on a high carbohydrate diet and administered [1,2-13C2]glucose confirmed a decreased level of pentose cycling during parasitism consistent with a lower level of lipogenesis. It is suggested, however, that the pentose pathway may facilitate the synthesis of trehalose from dietary carbohydrate by directing hexose phosphate cycled through the pathway to the production of energy.     

Mycophagy and its influence on habitat use and ranging patterns in Callimico goeldii

Mycophagy has been documented in a number of species of marmosets and lion tamarins (Callitrichinae) but its effect on ranging behavior is not known. We present the results of 10 years of research on five groups of Goeldi's monkey (Callimico goeldii) at a field site in northwestern Bolivia. We studied the diet and ranging behavior of two of the groups. On average, groups contained 4.5 individuals (range 2.0–9.0), but they gradually decreased in size until only the breeding female remained in the home range. The annual diet was composed of fungi (31.1–34.9%), fruits (34.0–40.6%), prey (17.4–30.1%), and exudates (1.0–10.9%). They had large home ranges (114–150 ha) and over time individuals tended to shift their core areas of use. They used secondary and bamboo forest and forest with dense understories more than expected based on availability. We suggest that the large home ranges and shifting core areas used by C. goeldii are components of a foraging strategy to track patchy, low density, and ephemeral fungal fruiting bodies. Our results, along with data published on other callitrichines, indicate that groups of Leontopithecus, Callithrix, and Callimico that eat fungi have larger home ranges than those that do not. Mycophagy is one of the several factors that evidently affect home range size in callitrichines. Fungi are clearly an important food source for a number of populations, but additional studies are needed to determine why some eat fungi frequently while others do not. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.     

Social organization, reproduction and rearing strategies of Callimico goeldii: new clues from the wild

The callitrichines are a specialized radiation of primates that are characterized in part by variable social systems and cooperative infant care. Callimico goeldii, unlike the other callitrichines, have single rather than twin offspring, reducing the need for allocare and permitting synchronous breeding within groups. Low mortality rates among offspring and unstable social groups are suggested to be possible factors that have led to single births among C. goeldii. Single offspring may benefit from greater maternal investment and more frequent food sharing than twin offspring, factors that may help to explain why C. goeldii reaches sexual maturity more rapidly than other callitrichines. In addition, increased breeding opportunities for young C. goeldii females may have selected for rapid maturation rates among this species. Postpartum ovulation and aseasonal resource availability appear to permit females to have biannual birth seasons, further increasing the potential reproductive output.     

Ingestion and diet destination in Culiseta inornata: responses to water, sucrose and cellobiose

ABSTRACT. At ambient temperature, contact with free liquids containing sugar induces Culiseta inornata Williston (Diptera: Culicidae) females to adopt the nectar-feeding mode of behaviour. While in this mode, two distinct control mechanisms appear to operate: one controlling the amount of ingestion, the other diet destination. Mosquitoes were exposed to water and various concentrations of sucrose and cellobiose in water. Only small or taste amounts of water were imbibed, and it was directed to the midgut. Cellobiose solutions of less than 0.1M were treated as water. Cellobiose was phagostimulatory; as the concentration increased from 0.1 to 0.5 M the percentage of insects ingesting large amounts rose from 11% to 68%. Cellobiose diets were directed primarily to the midgut. Sucrose was also phagostimulatory. As the concentration increased from 0.025 to 0.2 M, the percentage of insects ingesting large amounts increased from 20 to 92. At lower sucrose levels, insects ingesting large amounts put it mainly into the crop, while insects ingesting smaller amounts put the diet into the midgut or both the crop and midgut. At sucrose concentrations of 0.4 M or more, most insects took large amounts and directed it to the crop. Different combinations of sucrose and cellobiose with a total concentration of 0.5 M all caused insects to take mainly large meals. At sucrose concentrations of 0.2M and above, the insects responded as they would to sucrose alone, directing the diet to the crop. At sucrose concentrations of 0.1M or less, diet destination patterns were more complex, with individual animals depositing the diet in the crop, the midgut, or in both. A behavioural model is presented which postulates different receptors for sucrose and cellobiose, control of diet destination via differential control of midgut and crop valves, and variation of threshold values according to endogenous factors.     

Multitrophic web of insects associated with <Emphasis Type="Italic">Piptadenia gonoacantha</Emphasis> (Mart.) Macbr. (Fabaceae) and their relationship with resource traits

We describe for the first time the food web of insects associated with fruits and seed of Piptadenia gonoacantha (Fabaceae), and analyze their relationships with resource traits, such as biomass and fruit area. A total of 440 fruits of P. Gonoacantha were sampled in the city of Lavras, Minas Gerais, Brazil. We found twenty-one species of insects distributed in three trophic levels. The most widely sampled species was Acanthoscelides clitellarius (Coleoptera, Chrysomelidae, Bruchinae), the main consumer species of seeds. It was also verified the presence of Lepidoptera larvae consuming both seeds and the internal fruit tissue. Other species of herbivorous insects were found in low numbers. The food web was subdivided into one sub-web of 10 parasitoid species and one hyperparasitoid species associated to A. clitellarius and another one sub-web of four parasitoid species associated with Lepidoptera. For the parasitism rates, we obtained the following: 19.11% for the total food web, 17.93% for the A. clitellarius parasitism, and 36% for the Lepidoptera parasitism. The resource traits had influence on the oviposition behavior of A. clitellarius, where fruits with larger area showed more eggs of this species. Fruits with higher biomass showed greater abundance and richness of insects as well as more interactions. Seeds with higher biomass were more often used by herbivorous insects. The larval forms of Lepidoptera caused the greatest damage in seed biomass among herbivores. Seeds with parasitoids did not show a significant difference in biomass when compared to predated seeds.     

Foraging strategies of yakushima macaques (Macaca fuscata yakui )

I investigated the activity budget and diet of Yakushima macaques (Macaca fuscata yakui,)in warm temperate broad- leaved forest of Yakushima, Japan. Both time spent feeding and time spent moving varied considerably between half- months. However, total time spent in active behaviors— feeding time plus moving time— was stable. The composition of the diet also showed considerable variation between half- months. The macaques fed mainly on fruits, seeds,mature leaves, fallen seeds, flowers, and young leaves, each of which accounted for more than 30% of feeding time in at least 1 half- month. They also ate insects and fungi, but each of them comprised ≤ 25 and ≤ 8% of feeding time in any half- month, respectively. Time spent feeding on mature leaves, young leaves, flowers, or fallen seeds is positively correlated with total time feeding and is negatively correlated with time moving. In contrast, time feeding on fruits, seeds, insects or fungi is negatively correlated with time feeding and is positively correlated with time moving. Foraging on foods that have a low energy content, a high density, and a relatively even distribution— mature leaves— or that need much manipulation to be processed— flowers and fallen seeds— increased feeding time, while foraging on foods for which monkeys must search intensively in the forest— fruits, seeds, insects, and fungi— led to increased moving time. I examined foraging strategies of Yakushima macaques in terms of moving costs and the quality of food items. Regarding time feeding on fruits, which have more energy and may need less manipulation than other foods, as a benefit, and moving time as a cost, they seemed to employ a strategy that balanced the costs and benefits of foraging.     

Trichomycete fungi (Zygomycota) associated with the digestive tract of Simulium goeldii Cerqueira & Nunes de Mello and Simulium ulyssesi (Py-Daniel & Coscarón) (Diptera: Simuliidae) larvae,in Central Amazônia,Brazil

Trichomycete fungi are associated with digestive tract of black fly larvae. These fungi have not been studied in Brazil, knowing them and their relationship with black flies could be an alternative to control vector populations. The objectives of this study were to survey the Trichomycete fungi associated with larvae of Simulium goeldii and S. ulyssesi, and to determine if there is specificity and/or difference in the infection rates in these species. Black flies were collected in Central Amaz?nia, Brazil. Three genera of Trichomycetes were found: Harpella, Genistellospora and Smittium. All these fungi were common to both black fly species.     

青木川自然保护区川金丝猴食性的季节性变化

2005 ～2008 年于陕西省青木川自然保护区使用瞬时扫描法观察了川金丝猴的食性。结果表明,川金丝猴冬季和夏季共取食42 种植物,可鉴定植物归属23 科34 属。川金丝猴食物类型包括果实、花、树叶、树皮、树芽。夏季取食21 种植物的果实或树叶;冬季取食25 种植物。树叶是其冬季主要食物,取食频次占总取食频次的73.0% ;夏季取食果实的频次占总取食频次的72.2% ,灯台树果实是其主要食物。啃食树皮行为主要发生在落叶阔叶林、针叶林与落叶阔叶混交林;在常绿和落叶阔叶混交林中,树皮啃食强度则相对较小。与其它地区金丝猴的食性比较,该地区川金丝猴食物谱较宽。蔷薇科和壳斗科植物在川金丝猴食物组成中最多,杨柳科、桦木科、山茱萸科、槭树科和忍冬科植物也取食较多。     

Effects of Serum Lipid Smoothness on the Progression and Vulnerability of Atherosclerotic Plaques in Rabbits

Objective

We aimed to explore the effects of lipid smoothness on the progression and vulnerability of atherosclerotic plaques.

Approach

24 rabbits were divided into three groups randomly. Group 1 was given standard chow diet; group 2 was fed with cholesterol-rich diet; for group 3, subjects were planned to take cholesterol-rich diet at the first phase for 12 weeks and during the second phase, low-fat and cholesterol-rich diet was then applied alternately every three weeks till the end of the experiment. Lipid profiles, inflammatory factors, endothelium functions, pathological and histological changes were examined. Expressions of matrix metalloproteinase-9 and lectin-like oxidized LDL receptor-1 were measured by immunohistochemical staining.

Results

According to data collected during the whole experiment, lipid smoothness index of group 3 was the lowest. Compared with group 2, statistics of the group 3 indicated that: the development of plaques progressed faster; the plaque area and plaque thickness (53.53[22.6]% vs 33.90[24.91]% , 800.38[98.25]µm vs 675.00[109.67]µm) were higher while the fibrous cap thickness (103.50[45.66]µm vs 295.83[97.90]µm) was lower; hs-CRP (0.53[0.07]mg/dL vs 0.45[0.06]mg/dL), interleukin-18 (186.01[8.41]ng/L vs 158.08[2.37]ng/L), OX-LDL (177.15[5.93]µg/L vs 139.57[2.35] µg/L) and endothelin-1 (164.66[9.54]ng/L vs 131.52[4.39]ng/L) were higher while nitric-oxide (22.41[1.69]µmol/L vs 27.23[1.36]µmol/L) was lower; expressions of matrix metalloproteinase-9 (IOD: 37375.87[5634.52] vs 20956.57[4616.93]) and lectin-like oxidized LDL receptor-1 (IOD: 45213.04[16653.81] vs 21921.68[6142.32]) were higher.

Conclusions

Lipids fluctuation could accelerate the progression and vulnerability of atherosclerotic plaques through worsening arterial endothelium dysfunction and inflammatory reactions.     

Feeding ecology of the northern Ryukyu fruit bat, Pteropus dasymallus dasymallus, in a warm-temperate region

The warm-temperate fruit bat, Pteropus dasymallus dasymallus consumed at least 17 species of fruits, five of flowers, nine of leaves, one of bark and eight of insects. Soft fruits formed the bulk of its diet. Ficus eaten by the bat fruited asynchronously among individuals of the same species. In these species, the ratios of trees bearing ripe fruit to all trees cxamined each month were very low except for F. erecta. On the other hand, some plant species showed synchronous fruit production over a short period. Both types of plants supply fruits in every season. Seasonal dietary shifts and food choice were evident, and flowers, leaves or insects formed a small but nutritionally important component of the diet of the bat. The frequency of mastication was 124–155 per one pellet produced within a few minutes. The bat extracted and swallowed 61 82% ofthe fruits' wet weight and 58–73% of the insects' weight. The swallowed juice passed through the digestive systems in only 34 min on average. The bat ingested 0.5 times its body weight in figs per day. It is probablc that such a low food intake is adapted for the seasonal changes of food availability in the warm temperate region.     

Seasonal Food Use Strategies of <Emphasis Type="Italic">Semnopithecus vetulus nestor</Emphasis>, at Panadura and Piliyandala,Sri Lanka

Field studies on Semnopithecus vetulus have shown high folivory and the ability to feed heavily on mature leaves, which are constantly available. In research spanning 19 mo, I examined the feeding behavior of 2 free-ranging groups of Semnopithecus vetulus nestor in home gardens and rubber monocultures at Panadura (PT1 group) and Piliyandala (R1 group), Sri Lanka. Overall, results showed that >80% of their diet comprised seasonal plant parts, largely fruits. Despite differences in spatial and temporal food availability in their respective habitats, seasonal plant parts dominated the diets of both groups except briefly (2 mo) for R1 when mature leaf petioles were the main plant food. Both groups increased their use of seasonal foods with heightened seasonal food availability, and increased dietary diversity with declining use of their highest-ranked specific item of diet: fruits of Artocarpus heterophyllus (jakfruit, Moraceae). PT1, which was in a species-rich environment, maintained a high intake of seasonal foods year round by exploiting a large number of species, mainly for fruits. In contrast, R1, in a habitat with significantly lower tree species richness, had a less diverse diet but maintained an equally high intake of seasonal foods, primarily fruits and seeds, by exploiting a few species heavily. My study also highlights the dietary flexibility of a single colobine species in space and time. Such information is useful for conservation planning because rapidly occurring changes are taking place in natural colobine habitats.     

Spatial and seasonal changes in the diet of Oligosarcus hepsetus (Characiformes, Characidae) in a Brazilian reservoir.

We assessed spatial and seasonal changes in the diet of Oligosarcus hepsetus in order to describe the strategy developed by this species that allows their very high abundance in Lajes reservoir, Rio de Janeiro, Brazil. Fish samplings were carried out using gill nets, deployed during ca. 12 and 24 hours, between April 2001 and May 2002. A total of 289 individuals were examined, of which 97 showed gut contents. We used the index of relative importance (IRI) to compare probable dietary shifts, and the frequency of occurrence (% OC) to analyze possible ontogenetic influences on feeding. O. hepsetus showed carnivorous habits, feeding preferably on fish and insects, the latter of which occurred in 71.0% of the guts presenting contents. O. hepsetus consumed different items along the three reservoir zones: insects (61.0% IRI) and Cichla monoculus (38.9% IRI) in the lower zone; Lepidoptera (57.0% IRI) in the middle zone; and C. monoculus (77.0% IRI) in the upper zone. Food items changed seasonally with C. nonloculus predominating in autumn 2001, and Hymenoptera and Lepidoptera in the winter. In spring almost all food was Lepidoptera (99.8% IRI), while in the summer Hemiptera dominated in the diet. In autumn 2002 Hemiptera (97.0% IRI) was dominant, in significant contrast with the previous autumn. Individuals smaller than 190 mm SL fed heavily on insects, while fishes predominated in the diet of individuals larger than 190 mm SL. Shifts in prey-capture ability among length classes suggest decreasing intraspecific competition. A higher food plasticity seems to be the strategy employed by this opportunist species, which used food resources available in the reservoir.