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Prey Capture (prey + capture)

Distribution by Scientific Domains

Life Sciences	76%

Selected Abstracts

KILLER WHALE ATTACKS ON MINKE WHALES: PREY CAPTURE AND ANTIPREDATOR TACTICS

MARINE MAMMAL SCIENCE, Issue 4 2005
John K. B. Ford
Abstract We describe nine incidents of predation or attempted predation of minke whales (Balaenoptera acutorostrata) by mammal-hunting "transient" killer whales (Orcinus orca) in coastal waters of British Columbia, Washington, and southeastern Alaska. Pursuits of minke whales were characterized by prolonged chases on a straight heading at velocities of 15,30 km/h. In four of the nine cases the adultsized minke whale gradually outdistanced the killer whales, which abandoned the high-speed pursuit after 0.5,1 h. In one case the minke beached itself and died. Four attacks were successful. In one instance a subadult minke was killed in open water following a chase. In two cases the fleeing minke entered a confined bay and was killed by the killer whales. One adult minke was taken after apparently attempting to seek cover beside a large sailboat. Minke whales made no attempt to physically defend themselves and were killed by repeated ramming or by asphyxiation. Although killer whales are capable of sprinting speeds greater than those of minke whales, it appears that adult minkes can maintain higher sustained speeds and evade capture if sufficient space for an extended escape trajectory is available. Successful predation of minke whales in coastal waters is rare compared to pinnipeds and small cetaceans, the main prey of transient killer whales. [source]

Effects of the toxic dinoflagellate, Alexandrium fundyense on three species of larval fish: a food-chain approach

JOURNAL OF FISH BIOLOGY, Issue 1 2008
J. C. Samson
Sublethal behavioural effects of exposure to paralytic shellfish toxins (PST; saxitoxin and its derivatives) from the toxic dinoflagellate Alexandrium fundyense were investigated in newly settled winter flounder Pseudopleuronectes americanus, larval sheepshead minnow Cyprinodon variegatus and larval mummichog Fundulus heteroclitus through an A. fundyense,copepod,fish food chain. Consumption of as few as six to 12 toxin-containing copepods was lethal to the fishes. After consuming fewer toxin-containing copepods, all three fish species exhibited sublethal effects from vector-mediated exposure. Prey-capture ability of mummichogs was reduced in larvae that had consumed toxic copepods, Coullana canadensis. After consuming toxic C. canadensis or mixed copepods, mummichog larvae had reduced swimming performance. Swimming activity was also significantly reduced in winter flounder after consuming toxic copepods, including time spent in motion and distance travelled. Prey capture and predator avoidance were reduced in first-feeding sheepshead minnow larvae that had consumed toxic dinoflagellate cells. Adverse effects on prey capture or predator avoidance may reduce larval survival and facilitate the transmission of PST through the food web. This study provides baseline information on sublethal effects of PST exposure on fishes using a novel food-chain approach with zooplankton as vectors. [source]

Strategy-switching in the gaffing bat

JOURNAL OF ZOOLOGY, Issue 1 2007
V. L. G. Todd
Abstract Foraging in Daubenton's bats Myotis daubentonii, at two altitudinal locations along a river gradient in North Wales was investigated in relation to aerial insect density and to the density of prey on the water surface. Prey capture in Daubenton's bats consisted of aerial hawking, where prey was taken in the air, and trawling, where bats gaffed invertebrates from the water surface. Aerial hawking accounted for 86% of all prey capture attempts, despite aerial insect availability falling close to zero for much of the night. Conversely, prey density on the water surface was an order of magnitude higher than aerial prey density and increased through the night due to aquatic invertebrate drift. At the higher altitude site, M. daubentonii switched prey capture strategy to gaffing, possibly to reflect this change in prey availability on the water's surface, but at the lower altitude site, they maintained aerial hawking as the preferred strategy. The switch to gaffing may be inhibited by the significant downstream accumulation of large numbers of inedible exuviae of caddis flies, Trichoptera, at the low-altitude site, which form both acoustic clutter and increase the probability of capturing inedible prey, making foraging less efficient. These small altitudinal differences in foraging strategy should be factored into the design of future altitudinal bat foraging studies and if found to be a widespread strategy, taken into consideration by conservation planners when reviewing the habitat requirements of Daubenton's bats in river valleys within the United Kingdom. [source]

Diet-induced phenotypic plasticity in the skull morphology of hatchery-reared Florida largemouth bass, Micropterus salmoides floridanus

ECOLOGY OF FRESHWATER FISH, Issue 4 2005
A. P. Wintzer
Abstract , Hatchery-reared Florida largemouth bass, Micropterus salmoides floridanus, feed on inert pellet food while their wild counterparts capture elusive prey. Differences in levels of prey elusivity often mandate the use of alternate methods of prey capture. This study examines whether elusivity-based variation in prey capture translates to a phenotypic change during skull development, and if this change results in a functional difference in the feeding mechanism. The developmental pattern of the skull was conserved between hatchery and wild bass until 80,99 mm TL. At this point, wild bass quickly developed morphological changes of the jaw apparatus including a more fusiform head and elongated jaw structures. Natural development in hatchery bass, however, was retarded at this size. Post-release, the skulls of hatchery fish converged towards those of wild bass by 135 mm TL. Despite variation in skull development, no theoretical advantage in food capture was found between these two groups. Resumen 1. Los individuos de Micropterus salmoides floridanus criados en cautividad se alimentan de cápsulas inertes de comida mientras que sus congéneres salvajes capturan presas elusivas. A menudo diferencias en los niveles de elusividad de las presas permiten la utilización de métodos alternativos para capturar presas. Este estudio examina si la variación basada en la elusividad de la captura de presas se traduce en un cambio fenotípico durante el desarrollo del cráneo y si este cambio resulta en una diferencia funcional en el mecanismo de alimentación. 2. El patrón de desarrollo del cráneo se mantuvo entre individuos criados en cautividad y en individuos salvajes hasta los 80,99 mm longitud total. En este punto, los individuos salvajes desarrollaron rápidamente cambios en el aparato mandibular incluyendo una cabeza más fusiforme y estructuras mandibulares mas alargadas. Sin embargo, en individuos de cautiverio, el desarrollo natural se retrasó en este tamaño. 3. Tras una suelta, los cráneos de individuos procedentes de cautiverio convergieron hacia los individuos salvajes en los 135 mm longitud total. A pesar de la variación en el desarrollo del cráneo, no encontramos ninguna ventaja teórica en la captura de alimento entre estos dos grupos. [source]

SOCIALITY IN THERIDIID SPIDERS: REPEATED ORIGINS OF AN EVOLUTIONARY DEAD END

EVOLUTION, Issue 11 2006
Ingi Agnarsson
Abstract Evolutionary ,dead ends' result from traits that are selectively advantageous in the short term but ultimately result in lowered diversification rates of lineages. In spiders, 23 species scattered across eight families share a social system in which individuals live in colonies and cooperate in nest maintenance, prey capture, and brood care. Most of these species are inbred and have highly female-biased sex ratios. Here we show that in Theridiidae this social system originated eight to nine times independently among 11 to 12 species for a remarkable 18 to 19 origins across spiders. In Theridiidae, the origins cluster significantly in one clade marked by a possible preadaptation: extended maternal care. In most derivations, sociality is limited to isolated species: social species are sister to social species only thrice. To examine whether sociality in spiders represents an evolutionary dead end, we develop a test that compares the observed phylogenetic isolation of social species to the simulated evolution of social and non-social clades under equal diversification rates, and find that sociality in Theridiidae is significantly isolated. Because social clades are not in general smaller than their nonsocial sister clades, the spindly phylogenetic pattern,many tiny replicate social clades,may be explained by extinction rapid enough that a nonsocial sister group does not have time to diversify while the social lineage remains extant. In this case, this repeated origin and extinction of sociality suggests a conflict between the short-term benefits and long-term costs of inbred sociality. Although benefits of group living may initially outweigh costs of inbreeding (hence the replicate origins), in the long run the subdivision of the populations in relatively small and highly inbred colony lineages may result in higher extinction, thus an evolutionary dead end. [source]

MICRO- AND MACROEVOLUTIONARY DECOUPLING OF CICHLID JAWS: A TEST OF LIEM'S KEY INNOVATION HYPOTHESIS

EVOLUTION, Issue 10 2006
C. D. Hulsey
Abstract The extent to which elements of functional systems can change independently (modularity) likely influences the diversification of lineages. Major innovations in organismal design, like the pharyngeal jaw in cichlid fishes, may be key to a group's success when they relax constraints on diversification by increasing phenotypic modularity. In cichlid fishes, pharyngeal jaw modifications that enhanced the ability to breakdown prey may have freed their oral jaws from serving their ancestral dual role as a site of both prey capture and prey processing. This functional decoupling that allowed the oral jaws to become devoted solely to prey capture has been hypothesized to have permitted the two sets of cichlid jaws to evolve independently. We tested the hypothesis that oral and pharyngeal jaw mechanics are evolutionarily decoupled both within and among Neotropical Heroine cichlids. In the trophically polymorphic species Herichthys minckleyi, molariforms that exhibit enlarged molarlike pharyngeal jaw teeth were found to have approximately 400% greater lower jaw mass compared to H. minckleyi with the alternative papilliform pharyngeal morphology. However, oral jaw gape, lower jaw velocity ratios, anterior jaw linkage mechanics, and jaw protrusion did not differ between the morphotypes. In 40 other Heroine species, there was a weak correlation between oral jaw mechanics and pharyngeal jaw mass when phylogenetic history was ignored. Yet, after expansion of the cytochrome b phylogeny for Heroines, change in oral jaw mechanics was found to be independent of evolutionary change in pharyngeal jaw mass based on independent contrasts. Evolutionary decoupling of oral and pharyngeal jaw mechanics has likely played a critical role in the unparalleled trophic diversification of cichlid fishes. [source]

Nanostructured Materials: Microstructural and Biochemical Characterization of the Nanoporous Sucker Rings from Dosidicus gigas (Adv. Mater.

ADVANCED MATERIALS, Issue 4 2009
4/2009)
The cover image shows an SEM image of a squid tentacle, revealing the individual sucker rings. These toothed ringlike structures within the suckers provide additional gripping power during prey capture and handling. The background image depicts the nanoscale network of parallel tubular elements from which the rings are constructed. The structural, mechanical and biochemical properties of this wholly organic material is discussed in detail by David Kisailus, Henrik Birkedal, and co-workers on p. 401. [source]

Microstructural and Biochemical Characterization of the Nanoporous Sucker Rings from Dosidicus gigas

ADVANCED MATERIALS, Issue 4 2009
Ali Miserez
The individual toothed sucker rings of squid tentacles (highlighted in blue) provide additional gripping power during prey capture and handling. These rings comprise a nanoscale network of parallel tubular elements, as shown in the background image. The structural, mechanical, and biochemical properties of this wholly organic material are discussed in detail. [source]

Behavior, metamorphosis, and muscular organization of the predatory rotifer Acyclus inquietus (Rotifera, Monogononta)

INVERTEBRATE BIOLOGY, Issue 3 2010
Rick Hochberg
Abstract. The atrochid rotifer, Acyclus inquietus, is a sedentary predator that lives within the colonies of its prey, the rotifer Sinantherina socialis. After larvae infiltrate and become associated with the colony, they secrete a permanent gelatinous tube and undergo metamorphosis to the adult stage. We followed settlement and metamorphosis using bright-field microscopy to document specific larval behaviors after eclosion, and used epifluorescence and confocal microscopy of phalloidin-labeled specimens to visualize some of the morphological changes that occur during metamorphosis. Upon eclosion, larvae possess paired eyespots and a ciliated corona that functions strictly in locomotion. After leaving the parent's gelatinous tube, larvae eventually settle on unoccupied colonies of S. socialis or on other substrates if colonies are unavailable. Settlement involves a period of gliding among colony members before attachment with the foot and the secretion of a gelatinous tube. After settlement, there is a drastic reconfiguration of the corona that involves loss of the eyespots, loss of the coronal cilia, and the formation of the cup-shaped infundibulum, a deep depression in the anterior of the head that leads to the mouth. The development of the infundibulum involves the expansion of tissues around the mouth and is accompanied by a reorientation of the underlying musculature that supplies the infundibulum and allows its use in prey capture. The arrangement of the muscles in the trunk and foot regions, which contain outer circular (complete and incomplete) and inner longitudinal bands, remains unchanged between ontogenetic stages, and reflects the condition characteristic of other rotifers. [source]

Owls and rabbits: predation against substandard individuals of an easy prey

JOURNAL OF AVIAN BIOLOGY, Issue 2 2008
Vincenzo Penteriani
The interactions among the multiple factors regulating predator-prey relationships make predation a more complex process than previously thought. The degree to which substandard individuals are captured disproportionately seems to be better a function of the difficulty of prey capture than of the hunting techniques (coursing vs. ambushing predators). That is, when the capture and killing of a prey species is easy, substandard individuals will be predated in proportion to their occurrence in the prey population. In the present study, we made use of eagle owls Bubo bubo and their main prey, the rabbit Oryctolagus cuniculus: (a) the brightness of the white tails of rabbits seems to be correlated with the physical condition of individuals, (b) by using the tails of predated rabbits as an index of individual condition, we found that eagle owls seem to prefer substandard individuals (characterized by duller tails), and (c) by using information from continuous radiotracking of 14 individuals, we suggest that the difficulty of rabbit capture could be low. Although the relative benefits of preying on substandard individuals should considerably decrease when a predator is attacking an easy prey, we hypothesise that the eagle owl preference for substandard individuals could be due to the easy detection of poor individuals by a visual cue, the brightness of the rabbit tail. Several elements allow us to believe that this form of visual communication between a prey and one of its main predators could be more widespread than previously thought. In fact: (a) visual signalling plays a relevant role in intraspecific communication in eagle owls and, consequently, visual signals could also play a role in interspecific interactions, and (b) empirical studies showed that signals may inform the predator that it has been perceived, or that the prey is in a sufficiently healthy state to elude the predator. [source]

Effects of the toxic dinoflagellate, Alexandrium fundyense on three species of larval fish: a food-chain approach

Behavioural interactions between native smokey dace and introduced yellowfin shiner: implications from habitat selection theory for an ongoing invasion

JOURNAL OF FISH BIOLOGY, Issue 2003
C. M. Wagner
The occupation of adjacent, non-overlapping positions along environmental gradients by closely related and ecologically similar species has drawn considerable attention from ecologists over the past decades. Condition-specific competition, wherein competitive superiority varies with the abiotic environmental gradient, has been proposed as the major structuring force behind such distributions. These concepts, however, are generally applied to explain the contemporary distribution of organisms that share an evolutionary history. Our aim was to apply these concepts to the naive interactions between native and introduced fishes. In 1990 yellowfin shiner (Notropis lutipinnis) were introduced into the headwaters of the Little Tennessee River of western North Carolina, U.S.A. where it exhibits microhabitat preferences that overlap significantly with those of a threatened native minnow, the smokey dace (Clinostomus funduloides raneyi). Previous research has established that these drift-feeding minnows: (1) differ in their average ability to intercept drifting prey as a function of water velocity; (2) generally occupy focal-point velocities that maximize the rate of prey capture; and, (3) occasionally defend the forward positions in foraging aggregations that form in high quality patches. We present the results of a series of experiments designed to: (1) evaluate the role of aggression in the establishment and maintenance of preferred foraging positions in drift-feeding minnows; (2) test the effects of prey availability, group size, and velocity on dominance rank, spatial position in groups, and feeding rates of individuals; and, (3) evaluate the potential for condition-specific competition to establish competitive refugia for the native within the natural heterogeneity of mountain streams. [source]

Interspecific variation in sternohyoideus muscle morphology in clariid catfishes: Functional implications for suction feeding,

JOURNAL OF MORPHOLOGY, Issue 3 2007
Sam Van Wassenbergh
Abstract Depression of the hyoid apparatus plays a crucial role in generating suction, especially in fishes with a dorso-ventrally flattened head shape. It is generally assumed that shortening of the sternohyoideus muscle, which connects the hyoid to the pectoral girdle, contributes to hyoid depression. However, a recent study on the clariid catfish Clarias gariepinus has shown that this muscle does not shorten but elongates during this phase through retraction of the pectoral girdle. Here, we test whether this pattern is general among clariid catfish, or if variation in the morphology of the sternohyoideus may result in a different sternohyoideus behavior during hyoid depression. First, sternohyoideus mass, effective cross-sectional area, fiber length and fiber diameter were measured and compared for four clariid species. Next, velocity and magnitude of hyoid depression during prey capture (from high-speed videos), as well as patterns of sternohyoideus strain were analyzed (from high-speed X-ray videos) in these species. While morphology and hyoid depression performance varied considerably among these species, only the species with the most massive sternohyoideus, Gymnallabes typus, showed shortening of the sternohyoideus muscle during the initial part of the expansive phase. The data for Channallabes apus demonstrate that increasing the magnitude of hyoid depression does not necessarily require a shortening of the m. sternohyoideus, as it shows elongation of this muscle during hyoid depression. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source]

Functional morphology of prey capture in the sturgeon, Scaphirhynchus albus

JOURNAL OF MORPHOLOGY, Issue 3 2003
Andrew M. Carroll
Abstract Acipenseriformes (sturgeon and paddlefish) are basal actinopterygians with a highly derived cranial morphology that is characterized by an anatomical independence of the jaws from the neurocranium. We examined the morphological and kinematic basis of prey capture in the Acipenseriform fish Scaphirhynchus albus, the pallid sturgeon. Feeding pallid sturgeon were filmed in lateral and ventral views and movement of cranial elements was measured from video sequences. Sturgeon feed by creating an anterior to posterior wave of cranial expansion resulting in prey movement through the mouth. The kinematics of S. albus resemble those of other aquatic vertebrates: maximum hyoid depression follows maximum gape by an average of 15 ms and maximum opercular abduction follows maximum hyoid depression by an average of 57 ms. Neurocranial rotation was not a part of prey capture kinematics in S. albus, but was observed in another sturgeon species, Acipenser medirostris. Acipenseriformes have a novel jaw protrusion mechanism, which converts rostral rotation of the hyomandibula into ventral protrusion of the jaw joint. The relationship between jaw protrusion and jaw opening in sturgeon typically resembles that of elasmobranchs, with peak upper jaw protrusion occurring after peak gape. J. Morphol. 256:270,284, 2003. © 2003 Wiley-Liss, Inc. [source]

Implications of predatory specialization for cranial form and function in canids

JOURNAL OF ZOOLOGY, Issue 3 2009
G. J. Slater
Abstract The shape of the cranium varies widely among members of the order Carnivora, but the factors that drive the evolution of differences in shape remain unclear. Selection for increased bite force, bite speed or skull strength may all affect cranial morphology. We investigated the relationship between cranial form and function in the trophically diverse dog family, Canidae, using linear morphometrics and finite element (FE) analyses that simulated the internal and external forces that act on the skull during the act of prey capture and killing. In contrast to previous FE-based studies, we compared models using a newly developed method that removes the effects of size and highlights the relationship between shape and performance. Cranial shape varies among canids based on diet, and different selective forces presumably drove evolution of these phenotypes. The long, narrow jaws of small prey specialists appear to reflect selection for fast jaw closure at the expense of bite force. Generalists have intermediate jaw dimensions and produce moderate bite forces, but their crania are comparable in strength to those of small prey specialists. Canids that take large prey have short, broad jaws, produce the largest bite forces and possess very strong crania. Our FE simulations suggest that the remarkable strength of skulls of large prey specialists reflect the additional ability to resist extrinsic loads that may be encountered while struggling with large prey items. [source]

Sexual dimorphism in chelicerae size in three species of nuptial-gift spiders: a discussion of possible functions and driving selective forces

JOURNAL OF ZOOLOGY, Issue 3 2008
L. E. Costa-Schmidt
Abstract Positive allometric patterns observed for intersexual signalling characters are related to directional sexual selection, and supported by theoretical and empirical data. Recent models have shown that positive allometry may not hold as a rule if the influence of natural selection is added to the model. Here we tested these models applying traditional morphometrical techniques for the analysis of chelicerae sexual dimorphism and allometric patterns within the genus Paratrechalea: Paratrechalea azul, Paratrechalea galianoae and Paratrechalea ornata. Spider chelicerae are basically used for prey capture, but males of Paratrechalea also use the chelicerae to offer a nuptial gift during courtship, also presenting a clear size and colour sexual dimorphism supporting a possible role as a signal. Chelicerae size was male biased for all the variables studied and showed an isometric pattern, while females showed a higher variation. Our findings are in accordance with models of viability-related function for prey capture, questioning some statements proposed by the positive allometry model. [source]

Multiple measures of laterality in Garnett's bushbaby (Otolemur garnettii)

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 3 2010
David B. Hanbury
Abstract Behavioral laterality, a common measure of hemispheric specialization of the brain, has been examined in multiple tasks across several species of prosimian primates; however, there is inconsistency among findings between and within species that leaves many questions about laterality unanswered. Most studies have employed few measures of laterality, most commonly handedness. This study examined multiple measures of laterality within subjects in 17 captive-born Garnett's bushbabies (Otolemur garnettii) to assess the consistency of lateralized behaviors and to examine possible influences such as age, posture, novelty, and arousal to elucidate the relations between direction and strength of laterality. We measured reaching, turning bias, scent marking, tail wrapping, leading foot, side-of-mouth preference, and hand use in prey capture. Because autonomic arousal has been invoked as a determinant of strength of lateralization, we included multiple tasks that would allow us to test this hypothesis. All subjects were significantly lateralized on simple reaching tasks (P<0.01) and tail wrapping (P<0.01). Moreover, the number of animals lateralized on turning (P<0.01), leading limb (P<0.05), mouth use (P<0.01), and prey capture (P<0.01) was greater than would be expected by chance alone. There was consistency in the strength and direction of hand biases across different postures. Tasks requiring hand use were more strongly lateralized than tasks not involving hand use (P<0.001). The data do not support the assumption that arousal (as subjectively categorized) or novelty strengthens lateralized responding. The results of this study are discussed in terms of the effects of arousal, posture, and age on lateralized behavior. Am. J. Primatol. 72:206,216, 2010. © 2009 Wiley-Liss, Inc. [source]

The ecological morphology of darter fishes (Percidae: Etheostomatinae)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010
ROSE L. CARLSON
Darters are a species-rich radiation of small benthic and benthic-associated stream fishes that comprise approximately 20% of the diversity of the North American freshwater fish fauna. Here, we gather data from 165, or 87%, of described species and use this information to characterize the morphological diversity of the darter radiation. We focus on characters of the oral jaws known to function in prey capture and consumption in other perciform taxa in order to explicitly link morphological diversity to ecological diversity. In addition to a quantitative description of the morphospace occupied by darters, we identify several instances of significant morphological convergence. We also describe three groups of darter species that exhibit unusual jaw morphologies that are used in previously undescribed prey capture behaviours. Despite these new ecomorphs, we find that darters exhibit relatively low variation in trophic morphology when compared with two other radiations of teleost fishes, and that the observed variation is related more to differences in microhabitat use than to differences in prey type. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 30,45. [source]

Morphological correlates of ant eating in horned lizards (Phrynosoma)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2006
JAY J. MEYERS
The North American horned lizards (Phrynosoma) represent a morphologically specialized group of ant-eating lizards. Although variation in dietary fidelity is observed among the species, all appear to possess morphological specializations thought to be related to their ant-eating diets. Previous studies have examined morphological specialization in Phrynosoma, but they have not taken into account the phylogenetic relationships of its member species. In the present study, the morphological characteristics of the head, jaws and teeth that are thought to be important in prey capture and prey processing were examined to test whether variation in cranial morphology is associated with diet in lizards of the genus Phrynosoma. It is suggested that lizards of the genus Phrynosoma are indeed morphologically specialized and that ant-eating is associated with reduced dentition and an overall reduction in the robustness of morphological structures important in prey processing. Although this trend holds for the highly myrmecophagous species of Phrynosoma, a robust cranial morphology is apparent in the short-horned lizard clade (Phrynosoma ditmarsi, Phrynosoma douglasii, Phrynosoma hernandesi, Phrynosoma orbiculare), implying the ability to process a variety of dietary items. The present study suggests that additional feeding specializations exist within an already specialized clade (i.e. the short-horned lizard clade) and highlights the need for more detailed dietary and behavioural studies of feeding behaviour in this uniquely specialized group of lizards. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 13,24. [source]

Interspecific Competition and Niche Separation in Primates: A Global Analysis

BIOTROPICA, Issue 3 2009
Brian M. Schreier
ABSTRACT Primates are an extraordinarily well-known tropical forest, mammalian taxon. We investigated potential modes of niche separation in primates by identifying sympatric species with putatively similar niche characteristics and assessing potential competition using data gleaned from an extensive literature review. We defined competing species-pairs as (a) sympatric species in which (b) the body mass of the larger species was within 30 percent of the smaller species' mass and (c) the species had the same category of diet. A sample of 43 well-studied forests (7,20 per continent) provided 673 pairs of sympatric primate species. Of these, 45 pairs (7%) are potential competitors by our definition. Africa has the largest number of competing pairs (17 pairs), while Asia might have the highest percentage of competitors in each forest site (17%). Niche separation was investigated for each pair by examining them for each of eight possible modes of separation: detailed differences in diets (28% of potential competitors), use of different heights in the forest (25%), use of different types of forest (14%), use of different locations within the forest (11%), use of support branches of different diameters (7%), different ranging behavior (6%), different techniques of prey capture (4%), and differential timing of activity (4%). The use of different heights in the forest is the dominant form of potential separation in Africa (31% of competing species-pairs) and Asia (38%), while detailed differences in diet appears to be the primary mode of niche separation in the Americas (26%) and Madagascar (32%). [source]