Feeding Ecology Research Papers - Academia.edu (original) (raw)

Portuguese sole, Synaptura lusitanica, were collected from the Portuguese coast, between April 2001 and March 2002, to examine feeding habits, age and growth, and sexual cycle. Synaptura lusitanica fed on few prey items, its diet mainly composed of polychaeta, bivalvia and cephalochordata. Signi¢cant di¡erences were found between the proportion of prey items according to season, length class of ¢sh and coastal area. The main di¡erences related to ¢sh size were the higher ingestion of bivalvia by larger ¢sh, in the west coast area, and the increase in the important cephalochordata for ¢sh larger than 300 mm total length, in the south coastal areas. Polychaeta presented a lower importance in the spring^summer period while bivalvia increased its values in the autumn^winter period. Cephalochordata were more important in the autumn^winter period, but only for ¢sh larger than 300 mm total length and in the south coastal areas. Vacuity was extremely high (mean value of 52%). Ages of S. lusitanica were determined from sagittae otoliths. The length of ¢sh analysed varied from 157 mm to 480 mm, and the oldest ¢sh was age 8. The von Bertalan¡y growth equation parameters di¡ered little between sexes, being the asymptotic length obtained for females higher compared to males. The highest values of the gonadosomatic index were obtained in summer, which was the period when the highest percentage of individuals in the spawning stage were recorded. Therefore, the spawning season seems to be from mid-spring (May) until the end of summer (September).

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- Zoology, Plant Biology, Ecology, Feeding Ecology

The big (Raja binoculata), California (R. inornata), longnose (R. rhina), and sandpaper (Bathyraja kincaidii), skates are commonly found on soft-bottom regions of the central California continental shelf and upper slope. The feeding ecology of this assemblage was compared to evaluate the degree of trophic separation among species, based on the results of previous speciesspecific diet studies. Specimens were collected from fishery independent trawl surveys conducted during September 2002-March 2003 at depths of 9-536 m. Using single and compound measures, diet composition of small (£60 cm TL) and large (>60 cm TL) individuals were compared within continental shelf (£200 m) and slope (>200 m) regions using traditional, multivariate, and novel techniques. Diet compositions within size classes were similar in both regions. Diet compositions between size classes generally differed, however, with fishes more important and crustaceans (especially shrimps and euphausiids) less important in the diets of large individuals. Crabs contributed substantially to skate diet compositions on the shelf, but were uncommon prey items at deeper depths, probably because of their relative scarcity in slope waters. Conversely, cephalopods were common prey items at slope depths, but were rarely ingested at shelf depths. The studied skate assemblage appears to consist primarily of generalist crustacean and fish predators that exhibit high dietary overlap at similar sizes. It is possible that resource competition among skates and groundfish species has been reduced because of considerable recent declines in the biomass of upper trophic level groundfishes. Skates may therefore play important roles in contemporary benthic food web dynamics off central California.

- by Joseph Bizzarro
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- Zoology, Ecology, Composition, Feeding Ecology

The brown hare, a Leporid widespread in the world, is now dispersed across Argentina after its introduction at the end of the 19th century. Studies on hare feeding ecology are important to evaluate a potential competition with domestic and native wild herbivores. This study analyses the brown hare diet in relation to food availability, and dietary overlaps with several herbivores in northern Patagonia. Food availability was estimated by point-quadrat transects, and hare diet by microhistological analysis of faeces, carried out in five habitats in five seasonal samplings. Significant differences were detected by Kruskall-Wallis ANOVA with multiple comparisons by Tukey test. Feeding selection was detected by w 2 test, and dietary preferences by the confidence interval of Bailey. Grasses and chamaephytes were the most available plant categories, with Stipa, Panicum and Acantholippia as main species. Grasses and phanerophytes were the main dietary categories, including Poa, Panicum, Bromus, Adesmia and Prosopidastrum. The phanerophytes Prosopidastrum and Ephedra were more eaten in winter, when the main food item (Poa) presented lower availability. A higher dietary proportion of the chamaephyte Acantholippia occurred in rocky habitats, where the coarse dominant grasses were always avoided. Hares shared most food items with several wild and domestic herbivores in northern Patagonia. The lack of preference for forbs differentiates brown hares from other herbivores. However, hares exhibited important dietary similarities with plain and mountain vizcachas, goats and horses, and an interspecific competition for food is highly probable.

- by Fernando Videla
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- Zoology, Ecology, Seasonality, Feeding Ecology

The marine otter (Lutrafelina) lives exclusively along exposed rocky shorelines on the South American Pacific coast from Peru (6'9, to Cape Horn, Chile (56'S), and Isla de 10s Estados, Argentina. L. felina diet and its relationship to prey availability and energy content was assessed by spraint and prey remains analysis, direct observation, and the use of crab pots and fish traps, at four sites on the Valdivian coast in the south of Chile, between June 1999 and June 2000. Based on spraints analysis, the diet was composed of 25 species; 52% (13/25) of the species identified were crustaceans, 40% (10/25) were fish, and 8% (2/25) were mollusks. Crustaceans were found in 78% of 475 spraints, 100% of 929 prey remains, and 90.8% of prey determined by direct observation, fish in 20% of spraints and 9.0% of prey determined by direct observation, and mollusks in 2% of spraints and 0.2% of prey determined by direct observation. Observed seasonal variation in prey availability was reflected in the otter diet. Fourteen prey species were trapped; 43% (6114) were crustaceans and 57% (8/14) fish, crustaceans were 93% of 566 trapped individuals, fish 7%. L. felina showed opportunistic feeding behavior, selecting prey seasonally according to their availability rather than to their energy input.

- by Gonzalo Medina Vogel
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- Zoology, Ecology, Feeding Ecology, Marine Mammal Science

The silver arawana, Osteoglossum bicirrhosum, hunts along shorelines and within flooded forests in the Amazon River basin and supplements its limited consumption of aquatic vertebrates by leaping from the water to obtain terrestrial and arboreal prey. We offered O. bicirrhosum prey both suspended above and submerged below the surface of the water. From high-speed digital recordings, we measured kinematic variables associated with the jaws, cranium, pectoral fins, and body during orientation and prey capture. Aquatic and aerial feeding events were kinematically distinct, with aerial events generally involving faster, larger movements and a distinct delay in the onset of lower jaw depression until the head had left the water. The comparatively large gape during leaping may facilitate prey capture by overcoming variability in the apparent position of the prey due to refraction, while the delayed onset of mouth opening may serve to reduce the effects of drag. This distinctive leaping behaviour allows exploitation of the terrestrial prey base, especially during seasonal inundation of the Amazon River basin when the aquatic food base is widely dispersed.

- by Dayv Lowry
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- Zoology, Ecology, Feeding behaviour, Seasonality

Установлено, что из общей биомассы сообществ беспозвоночных в водоемах личинки сибирского углозуба (Hynobius keyserlingii Dyb.) используют лишь незначительную часть. Избираемость добычи личинками определяется характером ее движения, структурной защищенностью, размерной и пространственной доступностью. Обсуждается роль пищевого поведения в развитии личинок сибирского углозуба в онтогенетической динамике их питания.

- by Sergius Kuzmin
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- Amphibian Biology, Trophic Ecology, Feeding Ecology, Amphibia
- by Sergius Kuzmin
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- Caudatans, Evolutionary Ecology, Amphibian Biology, Trophic Ecology

The diet of Black-necked swans, Cygnus melancoryphus (Anatidae), was studied in two southern Chilean wetlands in 1993-1995; the Cruces River Sanctuary and the Chihuao-Pichoy River, both near Valdivia. The diet of swans was analyzed by using microhistologic techniques of cell remains in feces collected in the field. The analysis showed that swans were eating predominantly the most abundant submerged aquatic plant, Brazilian waterweed, Egeria densa (Hydrocharitaceae), at both Cruces River (91.9% of diet) and Chihuao-Pichoy River (71.7%). The foraging action of this species was estimated using four forage exclosures in the Chihuao-Pichoy River wetland free from swan grazing, which were compared with foraged controls. Aquatic plant biomass taken in the exclosures was significantly higher (p < 0.05) than biomass sampled outside the exclosures. Cygnus melancoryphus might play an important role as a regulator of aquatic plant biomass, thus contributing to cause a delay in ecological succession. The potential impact of this slowing down is discussed in terms of a natural ecological process in wetland environments.

- by Paulo Corti
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- Zoology, Feeding Ecology

Five captive adult female degus (Octodon degus) were offered leaves and twigs to eat from three woody (Adesmia bedwellii, Porlieria chilensis and Proustia pungens) and two suffruticose (Baccharis paniculata and Chenopodium petiolase) shrubs that provide cover in their natural habitat. The degus discriminated among the plant species, consuming lower amounts of P. chilensis. Daily body mass losses of degus were significantly higher when they were fed upon P. pungens and P. chilensis. The nutritional value of plants, concomitant with degu nutritional requirements, may explain changes in shrub cover previously found to follow removal of degus from experimental plots.

- by Francisco Bozinovic
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- Earth Sciences, Arid environments, Biological Sciences, Feeding Ecology
- by Sergius Kuzmin
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- Caudatans, Trophic Ecology, Feeding Ecology, Ecology of Amphibians and Reptiles

Blubber biopsy samples from eastern North Pacific killer whales Orcinus orca were analyzed for fatty acids, carbon and nitrogen stable isotopes and organochlorine contaminants. Fatty acid profiles were sufficiently distinct among the 3 reported ecotypes ('resident,' 'transient' or 'offshore') to enable individual animals to be correctly classified by ecotype and also by mitochondrial DNA (mtDNA) haplotype. Profiles of PCBs also enabled unambiguous classification of all 3 killer whale ecotypes, but stable isotope values lacked sufficient resolution. Fatty acid, stable isotope and PCB profiles of the resident and transient ecotypes were consistent with those expected for these whales based on their reported dietary preferences (fish for resident whales, marine mammals for transients). In addition, these ecotype profiles exhibited broad similarity across geographical regions, suggesting that the dietary specialization reported for resident and transient whales in the well-studied eastern North Pacific populations also extends to the less-studied killer whales in the western Gulf of Alaska and Aleutian Islands. Killer whales of the same ecotype were also grouped by region of sample collection. The mean stable isotope ratios of various regional groups differed considerably, suggesting that the prey preferences of these North Pacific killer whales may be both region and ecotype specific. Furthermore, 3 specific ecotypes of killer whales were found to have measured stable isotope values that were consistent with dietary preferences reported in the literature. Finally, although the offshore population had blubber fatty acid profiles implicating fish as its primary prey, contaminant and stable isotope results were equally congruent with predation on marine mammals.

- by Lance Barrett-Lennard
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- Zoology, Marine Ecology, Ecology, Feeding Ecology

The bill is a sexually dimorphic structure in many bird species and implicated in numerous functions. Sexual differences may arise from sexual selection or ecological divergence. Here, we examined differences in bill size and shape between males and females and explored to what extent these relate to feeding ecology of each sex in Cory's shearwater (Calonectris diomedea). We applied linear measurements and geometric morphometric methods to examine sexual differences in bill size and shape. We investigated feeding ecology by tracking foraging movements during the breeding period and by analysing stable isotope signatures in blood during the breeding period and in feathers grown during the non-breeding period. Bill traits were all sexually dimorphic, both in absolute and relative terms, and scaled hypermetrically with body mass in several characters in males. However, males and females did not differ in their feeding areas or isotopic signatures and no significant correlation was observed between these traits and bill dimorphism. Therefore, we discard the foraging-niche divergence hypothesis, and suggest that sexual dimorphism in bill size in this species is more likely driven by sexual selection related to antagonistic interactions.

- by Antigoni Kaliontzopoulou
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- Zoology, Sexual Selection, Natural Selection, Sexual dimorphism

The feeding of 2 sympatric larval myctophids, Diogenichthys laternatus and Triphoturus mexicanus aff. oculeus, was analyzed in an upwelling area off northern Chile (23° S, 71° W). Diel feeding period, feeding incidence, feeding selectivity and diet overlap was estimated under different environmental conditions: coastal and oceanic areas and 2 depth strata in summer and winter 1997. Analyses were based on

- by Humberto González
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- Zoology, Marine Ecology, Ecology, Feeding Ecology

SummaryThe north-west European population of Bewick’s Swan Cygnus columbianus bewickii declined by 38% between 1995 and 2010 and is listed as ‘Endangered’ on the European Red List of birds. Here, we combined information on food resources within the landscape with long-term data on swan numbers, habitat use, behaviour and two complementary measures of body condition, to examine whether changes in food type and availability have influenced the Bewick’s Swan’s use of their main wintering site in the UK, the Ouse Washes and surrounding fens. Maximum number of Bewick’s Swans rose from 620 in winter 1958/59 to a high of 7,491 in winter 2004/05, before falling to 1,073 birds in winter 2013/14. Between winters 1958/59 and 2014/15 the Ouse Washes supported between 0.5 and 37.9 % of the total population wintering in north-west Europe (mean ± 95 % CI = 18.1 ± 2.4 %). Swans fed on agricultural crops, shifting from post-harvest remains of root crops (e.g. sugar beet and potatoes) in November and...

- by Eileen Rees
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- Behavioral Sciences, Conservation Biology, Animal Behavior, Conservation

We determined the diet of the poorly-studied Middle Eastern wolves (Canis lupus) in central Iran in [2009][2010]. Food items consisted mainly of farmed chicken and domestic goat (i.e., anthropogenic resources) using both qualification and quantification methods. In contrast, we identified the remains of wild ungulates in negligible quantities. Our data simulations showed that poultry and goats are both primary food items of wolves in the study area. The relative importance of main prey items did not vary seasonally, and, although there were some minor differences in secondary food items, we did not reveal any seasonal effect in diet composition. The negligible consumption of wild prey strongly suggests that wolves are not, at present, a limiting factor for wild prey in our study area. Appropriate management of illegal dumping, in conjunction with excluding wolves and other carnivores from human refuse, would minimize the chance of human-carnivore encounters, wolf-livestock conflicts and, in turn, the persecution of carnivores. Our study contributed to our knowledge of the feeding ecology of the Middle Eastern wolves in areas with a relatively high abundance of anthropogenic foods and a moderately low abundance of wild prey.

- by Paolo Ciucci
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- Zoology, Mammalia, Feeding Ecology, Canis lupus
- by Lucas Milmann
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- Feeding Ecology, Dolphin behavior

The feeding ecology and trophic organization of 32 fish species found in an highly impacted waters from four sites of the eastern Johor Strait, Singapore has been studied. Among the wide variety of prey consumed, calanoid copepod (46.9% domination) was the most important dietary component of fishes in this ecosystem. In general, fishes show a narrow range in adaptive radiation of feeding habits, with only three main guilds identified. Spatially, a more complex guild was recorded for the habitat with more complex structure, although the number of guilds was consistent at three to four guilds. Seasonally, a change of guild organization was observed. Many fish species placed in one guild might be classified in another guild during a different season. This information facilitates the examination of complex associations of fishes and identifies groups of species that use similar resources within a specific community and can serve as a reference for feeding ecology of fishes in highly impacted tropical habitats.

- by SUKREE HAJISAMAE
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- Earth Sciences, Biological Sciences, Seasonality, Feeding Ecology
- by Sergius Kuzmin
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- Caudatans, Trophic Ecology, Feeding Ecology, Ecology of Amphibians and Reptiles

The dietary structure and distribution patterns of red foxes Vulpes vulpes in situations of different food supply in the coniferous-deciduous (mostly small-leaved) woodlands of northern Belarus were investigated. A total of 1526 scats of red foxes was analysed, and snowtracking of the species was performed each winter. Abundance of the main prey (small rodents, perching birds and hares) and wild ungulates supplying carrion for red foxes in the cold season were monitored. The results suggest that in northern Belarus red foxes had a diversified diet, consisting basically of different combinations of bank voles, Microtus voles, and wild ungulate carrion. The importance of carrion much increased in winter, while the proportions of birds and fruits grew during the warm season. In the ecologically rich woodland harbouring on clay soil, red foxes relied more on small rodents, while carrion and fruits appeared to be more important food item of the predator in the barren forested terrain dwelling on poor sandy deposits. During Microtus population outbreaks, red foxes more frequently fed on this prey. One-sixth lower density of red foxes was attributable to the forested terrain on sandy deposits compared to the woodland on clay soil, and a pronounced landscaperelated difference in the habitat selection by the predator was found.

- by Anna Sidorovich
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- Zoology, Population Dynamics, Seasonality, Feeding Ecology

Nitrogen inputs to coastal environments can considerably alter the abundance of primary producers. However, how herbivores modify their trophic signatures and adjust to changes in food resource conditions remains controversial. Here, we assess the effect of nutrient availability on the diet shifts of the two main Mediterranean herbivores, the Sparid fish Sarpa salpa L. and the sea urchin Paracentrotus lividus (Lmk.) that feed mostly on the seagrass Posidonia oceanica L. (Delile), epiphytes and benthic macroalgae. To do this, we (1) investigate the patterns of isotopic composition (d 13 C and d 15 N signatures) of the two herbivores and their potential food sources in three areas of contrasting nutrient conditions and, (2) we assess the diet shift along this nutrient gradient by estimating the isotopic nutrient enrichment (i.e., the contribution of d 13 C and d 15 N signatures in consumers' tissues relative to potential food sources). Food web signatures of d 13 C were similar among the three study sites, and no patterns of d 13 C shift were observed in their diets. In contrast, there was a consistent increase in N contents and d 15 N along the nutrient gradient for all primary producers and their consumers. The rate of d 15 N enrichment was also clearly distinctive between the two herbivores: in P. lividus it increased by 61% along the nutrient gradient, while in S. salpa it remained constant. Our results suggest that sea urchins behave as facultative omnivores and feed on vegetable or mixed diets depending on the trophic status of the system. It is unclear, however, if this modification is behavioral or the consequence of mere changes in the availability of food items, as animal epiphytes (e.g., hydrozoans, bryozoans and ascidians) can also became more abundant on seagrass leaves under increased nutrient conditions. In contrast, adult fish appear to feed on vegetal material independent of nutrient availability in the ecosystem.

- by Javier Romero
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- Marine Biology, Biological Sciences, Feeding Ecology, Environmental Sciences

We observed a group of capped langurs for 12 mo in the Pakhui Wildlife Sanctuary, Arunachal Pradesh, India. We recorded the time of feeding on different food plant species, food categories, and the feeding heights of monkeys in trees. Capped langurs spent 68% of their feeding time on leaves, 16% on flowers, and 16% on fruits. Feeding on leaves was consistently high (p<0.01) during the year, with the highest feeding in May (85%) and the lowest in January (47%). The seasonal difference in feeding on leaves is significant (p<0.05): it was higher in summer and during monsoon. The feeding time on flowers was maximal (35%) in March and that on fruits and seeds was minimal (38%) in January. Langurs ate 52 plant species throughout the year. The largest number of plants (6) were species of Moraceae, and langurs spent more feeding time (20%) on them alone. The number of plants eaten per month varied significantly (p<0.05). Langurs ate Gmelina arborea, Albizzia lucida, Ficus glomereta, and Makania micrantha throughout the year. They spent 44% of their feeding time in terminal canopies and their average feeding height was 30-35 m. This is the first study to examine the feeding ecology of capped langurs and provides baseline data for the species.

- by G. S. Solanki
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- Zoology, Primatology, Seasonality, Feeding Ecology

Although the role of macroinvertebrates in the nutrient cycling of the Indo-Pacific mangrove ecosystems is now a paradigm of ecological research, most of the research and scientific assumptions deal with decapod crustaceans alone. However, decapods are not the only representatives of mangrove macrobenthos and in certain mangals they are surely outnumbered by gastropods, especially by potamidids of the genus Terebralia. This paper aims at bridging the gap in the knowledge of the ecological role of the largest and most abundant potamidid species of the Indo-Pacific mangals, the semiterrestrial T. palustris. In particular we studied size structure and distribution in relation to micro-environmental factors and feeding ecology, both in terms of diet composition and grazing rate, of two populations of this gastropod colonising a Kenyan mangrove creek. In contrast to what has been described by various authors concerning other mangals, in our study site juveniles and adults of T. palustris were present throughout the whole forest, from the landward belt to the seaward fringe, locally reaching very high densities at various levels. Both life stages showed a preference for patches characterised by soil with high organic content; thus the habitat of juveniles largely overlapped with that of the adults, although they are known to occupy different ecological niches. Indeed, gut-content analysis confirmed that juveniles are detritivorous and adults are mainly leaf-litter consumers. In situ experiments on the grazing activity of the adult snails showed that, in contrast to the litter-consuming crabs, they feed in every light and tidal condition, for an hourly consumption rate of ~0.65 g per snail. Considering an average density of about 10.5 adults m−2, it is estimated that a total of 10.5 leaves m−2 are removed by adult snails in each tidal cycle (i.e. about every 6 h). T. palustris is the only leaf consumer capable of searching for food under water during high tide and is responsible for the removal of a great quantity of mangrove litter. The results of the present study strongly suggest that T. palustris plays a major role in the food web, mangrove litter degradation and nutrient cycling of the Kenyan mangal.

- by Sara Fratini
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- Marine Biology, Content Analysis, Ecological Niche Modeling, Biological Sciences

The ef{ects of reduced activity in the amphipod Garuruaras lossanuru on the foraging behaviour of naive and experienced cyprinid fish, Vimba elongata,,ü/ere tested experimentally. Prey mobility reduced latencies. Generally, larencies declined with increasing experience of the fish. Viruba snapped at prey and inconspicuous particles at a higher frequency when prey were mobile than when they where immobie. The frequency of snaps increased with experience. These results conform to predictions from the search rate hypothesis.

- by Franz Uiblein
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- Fish Biology, Predator-Prey Interactions, Animal Behaviour, Crustacean Biology
- by Franz Uiblein
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- Predator-Prey Interactions, Animal Behaviour, Crustacean Biology, Feeding Ecology

The teeth of every primate, living and extinct, are covered by a hard, durable layer of enamel. This is not unique: Almost all mammals have enamel-covered teeth. In addition, all of the variations in enamel structure that occur in primates are also found in other groups of mammals. Nevertheless, the very complexity of enamel and the variation we see in it on the teeth of living and fossil primates raise questions about its evolutionary significance. Is the complex structure of primate enamel adaptive? What, if anything, does enamel structure tell us about primate phylogeny? To answer these questions, we need to look more closely at the characteristics of prismatic enamel in primates and at the distribution of those characteristics, both in relation to our knowledge of primate dental function and feeding ecology and from a phylogenetic perspective.

- by Elizabeth Dumont
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- Evolutionary Biology, Archaeology, Anthropology, Evolutionary Anthropology

Several authors have proposed that papionin baboons provide appropriate analogs for early hominin niche differentiation. Savanna-dwelling baboons and australopiths both radiated around the same time after Neogene expansion of C 4 grasslands, likely experiencing similar environmental changes and faced with solving similar ecological problems. We explore the insights baboons may provide into dietary ecology of savanna-occupying hominins. We compare dietary information from stable isotope data for feces, hair, and tooth dentine collagen of modern chacma baboons (Papio ursinus) with dietary data for Plio-Pleistocene papionins and hominins from South African savannas. Results confirm that, like the australopiths, baboons consume substantial amounts of C 4 food sources. However, the magnitude of inter-and intraindividual variation in baboon diets across different seasons and habitats is less than that from specimens of Australopithecus africanus and Paranthropus robustus analyzed to date. Hominins also consumed greater amounts of C 4 resources. Thus, though the data demonstrate that the radiation of both primate groups was closely linked with the spread of C 4 grasslands, hominins Int J Primatol (were even more extreme ecological generalists than baboons were. The absence of a fixed-diet in papionins implies that it was unlikely that the more ecologically flexible hominins evolved specializations for any one food type, an interpretation consistent with recent carbon isotope, dental microwear, and ecomorphological studies. We propose that researchers place less emphasis on resolving the foods that were most important for hominin differentiation; instead, future research should focus on questions related to ecological generalism.

- by matt sponheimer
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- Zoology, Primatology, Feeding Ecology, Niche Differentiation

The mara is a near threatened Caviomorph, endemic to Argentina. Studies on feeding ecology allow assessment of the dietary adaptability of maras to habitat changes. The mara diet and food availability on two sampling sites, belonging to distinct landscapes of Northern Patagonia, were estimated using microhistological analysis and point-quadrat transects, over four seasons, and besides during an extended drought. Significant

- by Silvia Puig and +2
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- Zoology, Seasonality, Feeding Ecology, Patagonia

Domestic cats (Felis catus) have been introduced on many islands in the world and are responsible for much damage to native insular faunas. The worldwide success and spread of this opportunistic predator is generally associated with its trophic adaptability. We examined the diet of a long-established feral cat population on a small Mediterranean island through the analysis of 1,219 scats collected during a 4-year period. Our results confirm that feral cats are generalist predators, able to feed on a wide range of prey. However, only a few prey species formed the major part of its diet. Two introduced mammals and a Mediterranean endemic seabird provided 93% of the yearly biomass consumed by cats (ship rats, 70%; wild rabbits, 7%; and yelkouan shearwaters, 6%). Ship rats remained by far the staple prey for cats throughout the year, but the diet of feral cats was more diversified in spring and early summer, frequently including insects, reptiles, and migrant birds. Endemic yelkouan shearwaters were preyed upon most frequently in autumn and winter, that is, during the shearwaters' prelaying period. Because rats provide the majority of the food of cats, they could help to maintain or inflate this alien predator population with deleterious consequences to the endemic shearwater. A cat eradication campaign would help protect the population of shearwaters on this island.

- by Eric Vidal
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- Mammalogy, Biological Sciences, Feeding Ecology, Environmental Sciences

Page 1. Primary Research Paper Stable carbon isotope ratios for the gray whale (Eschrichtius robustus) in the breeding grounds of Baja California Sur, Mexico Javier Caraveo-Patino1,* &amp;amp;amp; Luis A. Soto2 1Centro de... more

- by Luis Soto
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- Earth Sciences, Biological Sciences, Feeding Ecology, Environmental Sciences

The food composition and feeding ecology of the Egyptian Mongoose Herpestes ichneumon populations inhabiting different localities of Egypt was studied using stomach contents analysis between February 2008 and June 2010. Laboratory analysis of twelve mongoose stomach contents showed that the food of the Egyptian Mongoose is highly diverse and includes mammals, birds, reptiles, fishes, insects (mainly of order Coleoptera), fruits and other vegetable materials. Diet composition shows seasonal and geographical variations that are apparently associated with changes in the availability of different food items.

- by Walid Fathy
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- Food composition, Feeding Ecology

Fraser's and spinner dolphins are known to feed on mesopelagic prey, bur their diets and feeding ecologies have not been compared in areas where they are observed together. In this study we examined the stomach contents of both species caught incidentally in a driftnet fishery for tuna in the eastern Sulu Sea. Importance of prey items was determined using the percent occurrence, percent number, and volumetric methods. Mesopelagic fishes, particularly myctophids (mainly Ceratoscopelus warmingi, Diaphus spp. and Myctophum asperum), were the most important component in the diet of spinner dolphins, whereas in Eraser's dolphins, mesopelagic cephalopods (Abraliopsis, Onychoteuthis, Histioteuthis, and Chiroteuthis), and crustaceans (Notostomos elegans, Acanthephyra quadrispinosa, and Acanthephyra carinata) appeared to be equally important as the myctophid species. Fraser's dolphins appeared to feed preferentially on larger prey and had more diversified prey (Shannon's diversity index = 1.2) than spinner dolphins (diversity index = 0.9). Vertical distributions of the prey items summarized from published literature indicate that spinner dolphins forage in the upper 200 m and probably occasionally to as deep as 400 m, whereas Fraser's dolphins have a wider vertical foraging range, from near the surface to probably as deep as 600 m.

- by Louella Dolar
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- Zoology, Ecology, Feeding Ecology, Marine Mammal Science

Aim: To evaluate the impact on food safety and health of consumers of mycotoxins contaminating many foods and increasing the incidence of serious diseases. Furthermore, to approach the environmental sustainability of the food system.
Methods: Review of the scientific literature on the topic.
Results: The current situation, with reference to contaminated foods and the descending health risks could be aggravated by the increase in global temperatures resulting from climate change induced by human activities. Practices for prevention, food strategies and detoxification are being studied with the aim to reduce the impact of the phenomenon.
Conclusions: The resulting image is serious and requires the start of the great food transformation invoked by the scientists but remaining largely only an intention of the international community.

- by David Grassi
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- Nutrition, Feeding Ecology, Mycotoxins, Enviromental Suistainability
- by Joanna Lambert
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- Evolutionary Biology, Archaeology, Anthropology, Evolutionary Anthropology

The Florida manatee (Trichechus manatus latirostris) is one of the most endangered marine mammals in the US To protect this species, it is important to understand the feeding ecology to de ne critical habitats. Manatees generally are considered to be strictly herbivious mammals that only incidentally consume animal species. This concept is based on the preponderence of freshwater vegetation, seagrasses, and algae that is found in most stomach content and fecal analyses.

- by Graham Worthy
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- Zoology, Feeding Ecology, Marine Mammal, Aquatic Mammals

In this paper we compare some socio-ecological traits of feral dogs and wolves in order to assess the social ecology of feral dogs in terms of its adaptive value in the natural environment, and to evaluate to what extent the domestication process altered the wolf's socio-ecological patterns. Referring to feral dogs as those dogs living in a wild state with no food and shelter intentionally provided by humans, and showing a continuous and strong avoidance of direct human contacts, we review the currently available information on feral dog ecology, and particular reference is made to a 3-year term project on feral dog ecology in Abruzzo, Italy. Through comparison of relevant behavioural and ecological features of both wolves and feral dogs, we hypothesize that some aspects of the feral dogs' ecology, having escaped natural selection pressures, represent primarily expression of "evolutionary inertia" or an epiphenomena of artificial selection. Fitness-related measures of sociality, demography, reproduction, space-use, activity patterns, and feeding ecology in feral dogs tend to support our original hypothesis: feral dogs are not reproductively self-sustaining, suffer from high rates of juvenile mortality, depend indirectly upon humans for food, co-optable individuals, and space, and their demography appears dominated by unpredictable mechanisms. However, further research is needed, especially concerning different ecological conditions and multi-generational time-scales, as well as the role that dominant breed-types and cross-breeding history within feral dog groups might play in the expression of the analyzed socio-ecological features.

- by Paolo Ciucci
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- Zoology, Natural Selection, Feeding Ecology, Space Use

La diversidad funcional permite analizar los papeles ecológicos de las especies y cómo su interacción influye sobre la estructura de los ecosistemas. Esta aproximación se constituye como un componente clave en el entendimiento de las dinámicas ecológicas de ecosistemas estratégicos para la conservación, como las sabanas inundables de la Orinoquia. Las sabanas han estado sometidas a cambios en su composición y estructura como consecuencia de la introducción de especies vegetales foráneas, de ganadería extensiva y de la quema indiscriminada. En este trabajo se realiza una aproximación a la diversidad funcional de los mamíferos de las sabanas inundables de Cravo Norte y Puerto Rondón. A partir de muestreos entre 2016 y 2018, se registraron 63 especies de mamíferos asociados a las sabanas inundables. Para estimar la diversidad funcional, se compilaron los atributos ecológicos de cada especie, incluyendo gremio trófico y categoría de amenaza nacional. En general, las sabanas están principalmente dominadas por procesos de regulación llevados a cabo por insectívoros, herbívoros y carnívoros, principalmente. Los gremios están compuestos de especies especialistas y altamente vulnerables a disturbios antrópicos. Estas especies, a través de sus papeles funcionales, están influyendo directa e indirectamente en la estructura vegetal de las sabanas inundables, moldeando así mismo la dinámica ecosistémica.

- by Angela Alviz
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- Conservation Biology, Conservation, Colombia, Functional Ecology

Understanding the ecological role of a species in an ecosystem and the dynamics of the communities depends largely on knowledge of the trophic relationships. We evaluated the feeding habits and the trophic ecology of the endemic Colombian stingray Potamotrygon magdalenae, integrating stomach content and isotopic analyses (13 C and 15 N). The samples were collected in the middle Magdalena River basin, Colom-bia, during artisanal fishing operations in the dry and rainy seasons. The stomach content analysis indicated that P. magdalenae fed on a high number of occasional items, such as seeds, Planariidae, Teleostei and Nema-toda, with Diptera being the dominant food component at the population level. There were no significant differences in diet between males and females. In contrast, isotopic analysis showed that Coleoptera was the most important food source assimilated by the species, followed by Ephemeroptera; Chironomidae and Tri-choptera made the lowest contributions. No significant differences in δ 13 C and δ 15 N were observed between the sexes or hydrological seasons. Estimates of the isotopic niche indicated that P. magdalenae has a narrower tro-phic niche than the teleost fishes present in the study area. The trophic level was identified as intermediate, suggesting that Potamotrygon magdalenae plays a role as a mesopredator in the food web in the study area.

- by Andrés Navia
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- Food webs, Feeding Ecology

The diet and feeding ecology of 12 cyprinid fishes were studied in the Thalayanai stream of southern India. The diet of Barbodes sarana, Danio aequipinnatus and Rasbora daniconius were specialized in terrestrial and aquatic insects. Hypselobarbus dobsoni and Garra mullya consumed vegetative matter and unicellular algae as their most important dietary component, respectively. Hypselobarbus curmuca and Hypselobarbus dubius specialized in crustaceans and molluscs. Puntius amphibious, Puntius bimaculatus, Puntius dorsalis, Puntius filamentosus and Puntius tambraparniei fed on variety of food resources (aquatic insects, algae and detritus) and their feeding intake varied between wet to dry seasons. Levin’s index of diet breadth showed the broadest diets for P. dorsalis in both seasons, whereas G. mullya had a narrow feeding spectrum in both seasons. Among co-existing species, diet overlaps were substantially low during both wet and dry season. These results suggest that feeding specialization and low diet overlap reduce inter-specific competition, allowing co-existence of these cyprinid fishes in this highly structured stream assemblage.

- by muthukumarasamy Arunachalam
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- Zoology, Ecology, Aquatic Insects, Seasonality

Objectives: The proximate and ultimate determinants that may have prompted some primates to shift from an arboreal to terrestrial feeding niche, whether due to environmental change, seasonality, and/or predation pressure, are poorly understood. Within a fragmented littoral forest in southeast Madagascar, an arboreal strepsirrhine population spends a large proportion of time on the ground, thus we aimed to identify which factors influence terrestrial feeding.
Methods: From January to December 2013, we conducted 103 full-day focal follows on three social groups of southern bamboo lemurs H. meridionalis. We continuously recorded feeding time on all arboreal and terrestrial items, as well as whether the focal individual was under the canopy or exposed, and the distance to their nearest conspecific neighbor. All observed food items were collected and analyzed for macronutrient content. Daily climatic variables (temperature, precipitation), resource seasonality, daily path length (DPL), along with dietary and predation risk proxies, were used as fixed effects in a linear mixed model, with the daily proportion of terrestrial feeding as the dependent variable.
Results: Our model indicated that daily terrestrial feeding increased at cooler temperature, was associated with reduced DPL, and the intake of dietary metabolizable energy increased as terrestrial feeding increased. All other fixed effects were not significant predictors.
Discussion: Our study provides a window into the ultimate determinants of niche expansion: ancestral primates, in absence of their primary resources, may have initially descended to the ground in peripheral population range areas where the benefits (e g., nutritional pay-off) outweighed the costs.

- by Timothy M Eppley and +1
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- Primatology, Animal Behavior, Behavioral Ecology, Primates
- by Richard Merritt
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- Zoology, Entomology, Aquatic Insects, Feeding Ecology

The Indo-Pacific lionfishes, Pterois miles and P. volitans, are now established along the U.S. southeast coast, Bermuda, Bahamas, and are becoming established in the Caribbean. While these lionfish are popular in the aquarium trade, their biology and ecology are poorly understood in their native range. Given the rapid establishment and potential adverse impacts of these invaders, comprehensive studies of their biology and ecology are warranted. Here we provide a synopsis of lionfish biology and ecology including invasion chronology, taxonomy, local abundance, reproduction, early life history and dispersal, venomology, feeding ecology, parasitology, potential impacts, and control and management. This information was collected through review of the primary literature and published reports and by summarizing current observations. Suggestions for future research on invasive lionfish in their invaded regions are provided.

- by A. Barse and +1
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- Invasive Species, Feeding Ecology

Howler monkeys exploit diffi cult-to-digest and potentially toxic food items such as mature leaves and unripe fruits; persist across an extreme range of habitat types, including highly disturbed forests; and have the most widespread geographical distribution of any genus of New World primate. Given evidence of dietary variability in the amount of monthly fruit, leaf, and fl ower consumption, howler monkeys provide an instructive model for examining relationships among foraging strategies, activity budgets, and patterns of habitat utilization. In this chapter we examined evidence for interspecifi c differences in dietary patterns and nutritional ecology within the genus Alouatta and identifi ed three dietary "syndromes" that are generally consistent with howler monkey phylogeny and biogeography. Specifi cally, we show that Mesoamerican howler monkeys and A. seniculus are characterized by a balanced leaf and fruit diet, Amazonian species by a fruit enriched diet, and Atlantic Forest and southern howler monkeys by a leaf-enriched diet. Finally, to be able to identify species-specifi c dietary strategies and syndromes across the primate Order, we recommend an approach that includes collecting data on feeding rates and the nutritional composition of the diet.

- by Nicoletta Righini
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- Primatology, Feeding Ecology, Nutritional Ecology, Feeding Biology

Hexaplex trunculus (Linnaeus, 1758) is one of the most abundant and widespread muricid gastropods in the Northern Adriatic Sea, but relatively little is known about the feeding ecology of this predator. We examined the activity of H. trunculus on a sublittoral mussel bed at 24 m depth through in situ time-lapse observations and bulk samples. The camera photographed a 0.25 m2 section of the mussel bed at 6-min intervals for ~ 23 h. Photos were examined frame-by-frame for gastropod movement and activities, especially interactions between H. trunculus and Mytilus galloprovincialis (Lamarck, 1819). Our survey indicates high activity-levels of H. trunculus on the sea floor: all gastropods made minor movements, most made major movements, and most left the field of view during the study-interval. On average, individuals remained stationary for only 7.3 h. Two predation attempts on Mytilus involving conspecific competition were documented, and one Hexaplex was consuming a mussel at the onset of the deployment. Additionally, 487 M. galloprovincialis from four diver-taken 0.25 m2 quadrates were measured and examined for traces of marginal chipping and drilling predation. Mytilus from surface samples ranged from 11.1 mm to 95.5 mm in length, and one of the four samples had a significantly different average shell length from the others. 114 H. trunculus were collected and measured. Hexaplex ranged from 22.1 mm to 86.1 mm and the mean shell length did not differ among samples, though they were overwhelmingly medium and large. Predation frequency (the ratio of successfully preyed upon bivalves to the total number of bivalves sampled) is high at the studied site (> 55%), and large gastropods preferred a chipping mode of predation to drilling, supporting earlier laboratory studies showing a preference for M. galloprovincialis and this predation strategy. Prey effectiveness (the ratio of failed predatory attacks to total predatory attacks) is also high (63.8%), and no evidence of a size refuge was found. Feeding in H. trunculus is highly facultative, calling for caution when using drill holes to estimate predation intensities; whenever possible, traces of multiple predation modes should be considered.

Studies of food relations are important to our understanding of ecology at the individual, population and community levels. Detailed documentation of the diet of large-bodied, widespread snakes allows us to assess size-dependent and geographical variation in feeding preferences of gape-limited predators. Furthermore, with knowledge of the food habits of sympatric taxa we can explore possible causes of interspecific differences in trophic niches. The feeding ecology of the North American gopher snake, Pituophis catenifer , was studied based on the stomach contents of more than 2600 preserved and free-ranging specimens, and published and unpublished dietary records. Of 1066 items, mammals (797, 74.8%), birds (86, 8.1%), bird eggs (127, 11.9%), and lizards (35, 3.3%) were the most frequently eaten prey. Gopher snakes fed upon subterranean, nocturnal and diurnal prey. The serpents are primarily diurnal, but can also be active at night. Therefore, gopher snakes captured their victims by actively searching underground tunnel systems, retreat places and perching sites during the day, or by pursuing them or seizing them while they rested at night. Gopher snakes of all sizes preyed on mammals, but only individuals larger than 40 and 42 cm in snout-vent length took bird eggs and birds, respectively, possibly due to gape constraints in smaller serpents. Specimens that ate lizards were smaller than those that consumed mammals or birds. Gopher snakes raided nests regularly, as evidenced by the high frequency of nestling mammals and birds and avian eggs eaten. Most (332) P. catenifer contained single prey, but 95 animals contained 2-35 items. Of the 321 items for which direction of ingestion was determined, 284 (88.5%) were swallowed head-first, 35 (10.9%) were ingested tail-first, and two (0.6%) were taken sideways. Heavier gopher snakes took heavier prey, but heavier serpents ingested prey with smaller mass relative to snake mass, evidence that the lower limit of prey mass did not increase with snake mass. Specimens from the California Province and Arid Deserts (i.e. Mojave, Sonoran and Chihuahuan Deserts) took the largest proportion of lizards, whereas individuals from the Great Basin Desert consumed a higher percentage of mammals than serpents from other areas, and P. catenifer from the Great Plains ate a greater proportion of bird eggs. Differences in prey availability among biogeographical regions and unusual circumstances of particular gopher snake populations may account for these patterns. Gopher snakes have proportionally longer heads than broadly sympatric Rhinocheilus lecontei (long-nosed snake), Charina bottae (rubber boa) and Lampropeltis zonata (California mountain kingsnake), which perhaps explains why, contrary to the case in P. catenifer , the smaller size classes of those three species do not eat mammals.

- by Javier A Rodríguez-Robles
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- Feeding Ecology, Snakes, Feeding Behavior

Algal flora of the sandy substrate and faeces of clypeasteroids Scaphechinus mirabilis and Echinarachmus parma in Troitsa Bay Japan Sea are studied. 52 microalgae species, among which was dominated by representatives of Bacillariophyta (44), was registered. More low composition species of diatoms faeces (29 species), compared with a sandy substrate (52), as well as the predominance of their cells with chloroplasts, testifies about selective in clypeasteroids feeding. High similarity of algae flora in S. mirabilis and E. parma faeces (0.97) indicates the similarity in food specialization of these clypeasteroids living in the same ecological niche. Largely confirmed the assumption about essential role of diatoms in feeding clypeasteroid S. mirabilis.

- by Y. Elkin and +1
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- Feeding Ecology, Benthic Diatoms, Sea Urchins

Abstract
The aim of the present study was to work out the natural food and feeding habits of Macrobrachium
dayanum in Gho-Manhasa Stream Jammu. Samples were collected monthly between January 2004 and
December 2004. A total of 480 specimens of Macrobrachium dayanum (M. dayanum) were analysed by
categorizing them into four categories based on size and sex. Out of total 480 analysed specimens 214
(44.58%) guts were found to be empty while about 266 (55.41%) contained food. The frequency of
empty stomachs decreased with increasing size. Index of preponderance revealed that detritus was the
dominant food item of M. dayanum. Algae, the second most dominant food item was found to decrease
with increase in size. After detritus and algae other important food items were found to be insecta, sand,
annelids, macrophytes, mollusca, unidentified matter, crustacean and Rotifers. Based on overall analysis
of different size groups the M. dayanum has been categorized as detriti-omnivore feeding on both animal
and plant matter with detritus as dominant food item.
Keywords: Macrobrachium dayanum, natural food, gut content analysis, index of preponderance,
Jammu.

- by Yahya Bakhtiyar
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- Feeding Ecology

Different foods require different digestive processing. This simple fact has led to a wide adaptive variety in digestive systems. This chapter considers the relationship between the size of three digestive organs (stomach, intestine, and liver) and food intake, diet type (e.g. degree of softness/hardness in the case of carnivores and fiber-content in the case of herbivores), and seasonal factors. Our arguments are based on comparisons of diet-organ size associations within ecologically and phylogenetically uniform groups and on analyses of organ size changes within species and individuals. The phenotypic flexibility of the digestive organs is considerable; changes of 10-100% in organ size in response to changing conditions are found in a wide range of bird groups. Experimental work has shown changes in gizzard size of 50-100% in just 5-7 days. Ease of breakdown of food (a function of the strength of protective hard parts or the amount of fibrous ingredients) and total food intake determine the size of the stomach (and more specifically, its muscular part, the gizzard). Food intake also influences the size of the small intestine and the liver. Among waders (Suborder Charadrii), taxa consuming and crushing hard-shelled mollusks also have a heavier intestine (but not liver) than taxa eating softer foods. Much work remains to be done investigating the fine-tuning of capacities among the different digestive organs, the precise trade-offs involved in organ size changes, and the genetic basis of organ size and flexibility.

- by Theunis Piersma
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- Feeding, Feeding Ecology, Digestive Tract