Feeding ecology of thirteen syntopic species of anurans in a seasonal tropical environment.
TL;DR: Investigating the diets and patterns of coexistence in this group of ecologically similar species of anurans at the Río Llullapichis in Amazonian Perú finds similarity in diet within guilds tends to be lowest in the dry season when food is less abundant, suggesting that food is in short supply in thedry season.
Abstract: Thirteen species of anurans belonging to three families forage diurnally for arthropods in the leaf litter of the lowland rainforest at the Rio Llullapichis in Amazonian Peru. This paper investigates the diets and patterns of coexistence in this group of ecologically similar species. All thirteen species use the forest floor habitat without apparent differentiation. Most species take prey in proportions significantly different from those occurring in the leaf litter and comprise two specialist guilds: dendrobatids and bufonids that eat hard-bodied, slow-moving arthropods such as ants and mites; and leptodactylids that eat soft-bodied, mobile arthropods, primarily orthopterans and large spiders. Dendrobates femoralis (Boulenger) is a generalist, taking prey in proportions not significantly different from those in the leaf litter. Within specialist guilds, body sizes of species vary and are correlated with the size of prey taken. Foraging behavior and predator defense also correlate with the type and sizes of prey taken. Ant specialists tend to be poisonous and active searchers, taking many small prey per day. Non-ant specialists are cryptic, sit-and-wait foragers that take few large prey per day. Similarity in diet within guilds tends tobe lowest in the dry season when food is less abundant, suggesting that food is in short supply in the dry season.
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TL;DR: A new, monophyletic taxonomy for dendrobatids is proposed, recognizing the inclusive clade as a superfamily (Dendrobatoidea) composed of two families (one of which is new), six subfamilies (three new), and 16 genera (four new).
Abstract: The known diversity of dart-poison frog species has grown from 70 in the 1960s to 247 at present, with no sign that the discovery of new species will wane in the foreseeable future. Although this growth in knowledge of the diversity of this group has been accompanied by detailed investigations of many aspects of the biology of dendrobatids, their phylogenetic relationships remain poorly understood. This study was designed to test hypotheses of dendrobatid diversification by combining new and prior genotypic and phenotypic evidence in a total evidence analysis. DNA sequences were sampled for five mitochondrial and six nuclear loci (approximately 6,100 base pairs [bp]; x¯ = 3,740 bp per terminal; total dataset composed of approximately 1.55 million bp), and 174 phenotypic characters were scored from adult and larval morphology, alkaloid profiles, and behavior. These data were combined with relevant published DNA sequences. Ingroup sampling targeted several previously unsampled species, including Ar...
577 citations
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...…et al., 2001; Pröhl and Berke, 2001; Pröhl, 2003; Narins et al., 2003, 2005; Summers and McKeon, 2004), diet specialization (Silverstone, 1975a, 1976; Toft, 1980,1995; Donnelly, 1991; Caldwell, 1996; Parmelee, 1999; Darst et al., 2005), predation (Test et al., 1966), resource use and…...
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01 Jan 1985
TL;DR: The results suggest that fruit—eating birds face many of the constraints imposed on other gape—limited foragers, but have an unusual minimum—size relationship with their food because of the unique characteristics of fruits.
Abstract: In most animals, especially those that must swallow food items whole, prey size is related directly to predator size. This paper examines gape limitation and the influence of fruit size on diet in fruit-eating birds, drawing on data gathered over a 5-yr period on 70 bird species and 171 plant species in the lower montane forests of Monteverde, Costa Rica. The results suggest that fruit- eating birds face many ofthe constraints imposed on other gape-limited foragers, but have an unusual minimum-size relationship with their food because ofthe unique characteristics of fruits. Fruit-eating birds with broad gapes consumed more lauraceous fruit species and a larger mean and maximum size of fruits overall than narrow-gaped birds. However, the size of the smallest fruits eaten was not correlated with gape width; large-gaped species commonly fed on diminutive fruits. Birds effectively selected among individual fruits within a tree on the basis of fruit size, dropping bulky fruits beneath the tree. Effective size selectivity also occurred among trees of different species in the same family and among plant species in various families. The diet of broad-gaped birds was not comprised dif- ferentially of large fruit species. For example, Three-wattled Bellbirds favored medium-sized fruits, whereas Long-tailed Manakins took individual fruits in the same proportions as they took fruit species of different mean fruit diameters. Gape limitations and effective size selectivity have obvious con? sequences for seed dispersal patterns: plants with large fruits attracted fewer species of birds than plants with small fruits. Moreover, the broad-gaped bird species on which large-fruited plants spe- cialized were those with the most generalized diets.
518 citations
TL;DR: Constraints imposed by the structure of the vegetation and by the types and abundances of prey determine the available foraging opportunities and may affect the foraging traits of birds that can successfully exploit a particular habitat, and hence influence the patterns of bird habitat selection and community structure.
Abstract: The different searching tactics of passerine birds foraging for arthropods among the foliage of a northern hardwoods forest result in the capture of different kinds of prey. Five major searching modes are employed by the 11 foliage-foraging bird species in the Hubbard Brook Exper- imental Forest, New Hampshire. These are distinguished primarily by the rates and distances moved by the searching birds and by the types and forms of their prey-attacking maneuvers. These in turn reflect how large an area is scanned, how thoroughly it is searched, and how the bird moves from perch to perch in its search for prey. Mean searching and prey-attacking flight distances are positively correlated, indicating that birds move just far enough on average to take them into areas they have not previously searched visually. Likewise, birds that move rapidly while searching make significantly more prey attacks per unit time and hence encounter prey more often. Slow searchers scrutinize substrates more thoroughly and seem to take more cryptic and often larger prey. The results suggest that there are limitations on the ways that birds can search for and capture arthropod prey among foliage. We hypothesize that constraints imposed by the structure of the vegetation and by the types and abundances of prey determine the available foraging opportunities. Such habitat parameters may affect, in ecological or evolutionary time, the foraging traits of birds that can successfully exploit a particular habitat, and hence influence the patterns of bird habitat selection and community structure.
511 citations
TL;DR: The authors examined gape limitation and the influence of fruit size on diet in fruit-eating birds, drawing on data gathered over a 5-yr period on 70 bird species and 171 plant species in the lower montane forests of Monteverde, Costa Rica.
Abstract: In most animals, especially those that must swallow food items whole, prey size is related to predator size. This paper examines gape limitation and the influence of fruit size on diet in fruit—eating birds, drawing on data gathered over a 5—yr period on 70 bird species and 171 plant species in the lower montane forests of Monteverde, Costa Rica. The results suggest that fruit—eating birds face many of the constraints imposed on other gape—limited foragers, but have an unusual minimum—size relationship with their food because of the unique characteristics of fruits. Fruit—eating birds with broad gapes consumed more lauraceous fruit species and a larger mean and maximum size of fruits overall than narrow—gaped birds. However, the size of the smallest fruits eaten was not correlated with gape width; large—gaped species commonly fed on diminutive fruits. Birds effectively selected among individual fruits within a tree on the basis of fruit size, dropping bulky fruits beneath the tree. Effective size selectivity also occurred among trees of different species in the same family and among plant species in various families. The diet of broad—gaped birds was not comprised differentially of large fruit species. For example, Three—wattled Bellbirds favored medium—sized fruits, whereas Long—tailed Manakins took individual fruits in the same proportions as they took fruit species of different mean fruit diameters. Gape limitations and effective size selectivity have obvious consequences for seed dispersal patterns: Plants with large fruits attracted fewer species of birds than plants with small fruits. Moreover, the broad—gaped bird species on which large—fruited plants specialized were those with the most generalized diets.
508 citations
TL;DR: A variety of factors may cause community-wide patterns such as resource partitioning, and the relative importance of these factors may differ among taxa and among communities at different geographic locations.
Abstract: patterns result from three categories of causes, of which competition is just one; the other two are predation and factors that operate independently of interspecific interactions, such as physiological constraints. Moreover, in each of the case histories presented below, we find two or more mechanisms interacting in complex ways. In no case does a single factor, for example competition, ever act alone. These case histories therefore provide an admonishment to single-minded tests of community-wide patterns that pit competition against everything (or nothing) else. Rather, a variety of factors may cause community-wide patterns such as resource partitioning, and the relative importance of these factors may differ among taxa and among communities at different geographic locations.
471 citations
References
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Book•
01 Jan 1956
TL;DR: This is the revision of the classic text in the field, adding two new chapters and thoroughly updating all others as discussed by the authors, and the original structure is retained, and the book continues to serve as a combined text/reference.
Abstract: This is the revision of the classic text in the field, adding two new chapters and thoroughly updating all others. The original structure is retained, and the book continues to serve as a combined text/reference.
35,552 citations
TL;DR: The total number of species is proportional to the total range of the environment divided by the niche breadth of the species, which is reduced by unequal abundance of resources but increased by adding to the dimensionality of the niche.
Abstract: 1. There is a limit to the similarity (and hence to the number) of competing species which can coexist. The total number of species is proportional to the total range of the environment divided by the niche breadth of the species. The number is reduced by unequal abundance of resources but increased by adding to the dimensionality of the niche. Niche breadth is increased with increased environmental uncertainty and with decreased productivity. 2. There is a different evolutionary limit, L, to the similarity of two coexisting species such that a) If two species are more similar than L, a third intermediate species will converge toward the nearer of the pair. b) If two species are more different than L, a third intermediate species will diverge from either toward a phenotype intermediate between the two.
3,946 citations
"Feeding ecology of thirteen syntopi..." refers background in this paper
...How do these species coexist? Is there a limit to how similarly they can use common resources that may often be in short supply (MacArthur and Levins, 1967)? According to the ~ theory of limiting similarity," species ought to show regular, not random, differences in their use of resources; empirical work shows that species differ most commonly in three ways: in the space they occupy, in what they eat; or when they are active (Schoener, 1974a)....
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TL;DR: The address of the president of a society, founded largely to further the study of evolution, at the close of the year that marks the centenary of Darwin and Wallace's initial presentation of the theory of natural selection.
3,717 citations
TL;DR: To conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way.
Abstract: To understand resource partitioning, essentially a community phenomenon, we require a holistic theory that draws upon models at the individual and population level. Yet some investigators are still content mainly to document differences between species, a procedure of only limited interest. Therefore, it may be useful to conclude with a list of questions appropriate for studies of resource partitioning, questions this article has related to the theory in a preliminary way. 1) What is the mechanism of competition? What is the relative importance of predation? Are differences likely to be caused by pressures toward reproductive isolation? 2) Are niches (utilizations) regularly spaced along a single dimension? 3) How many dimensions are important, and is there a tendency for more dimensions to be added as species number increases? 4) Is dimensional separation complementary? 5) Which dimensions are utilized, how do they rank in importance, and why? How do particular dimensions change in rank as species nuimber increases? 6) What is the relation of dimensional separation to difference in phenotypic indicators? To what extent does the functional relation of phenotype to resource characteristics constrain partitioning? 7) What is the distance between mean position of niches, what is the niche standard deviation, and what is the ratio of the two? What is the niche shape?
3,626 citations
Book•
01 Jan 1975
TL;DR: This chapter discusses the evolution of Species Abundance and Diversity in Communities Near Equilibrium and some Mechanisms Producing Structure in Natural Communities, as well as some mechanisms producing structure in natural communities.
Abstract: Introduction Martin L. Cody and Jared M. Diamond Bibliography of Robert MacArthur I. The Evolution of Species Abundance and Diversity 1. Evolution in Communities Near Equilibrium Richard Levins 2. Population Fluctuations, Community Stability, and Environmental Variability Egbert G. Leigh, Jr. 3. Environmental Fluctuations and Species Diversity John W. MacArthur 4. Patterns of Species Abundance and Diversity Robert M. May 5. On Continental Steady States of Species Diversity Michael L. Rosenzweig II. Competitive Strategies of Resource Allocation 6. Selection for Optimal Life Histories in Plants William M. Schaffer and Madhav D. Gadgil 7. Prey Characteristics and Predator Niche Width Henry A. Hespenheide 8. The Temporal Component of Butterfly Species Diversity Arthur M. Shapiro 9. Markovian Processes of Forest Succession Henry S. Horn III. Community Structure 10. Towards a Theory of Continental Species Diversities Martin L. Cody 11. Ecomorphological Configurations and Convergent Evolution James R. Karr and Frances C. James 12. Niche Relations of Desert Lizards Eric R. Pianka 13. Geographical Ecology of Desert Rodents James H. Brown 14. Assembly of Species Communities, Jared M. Diamond 15. Structure of Stream Communities Ruth Patrick 16. Some Mechanisms Producing Structure in Natural Communities Joseph H. Connell IV. Outlook 17. Variations on a Theme by Robert MacArthur G. Evelyn Hutchinson 18. Applied Biogeography Edward 0. Wilson and Edwin 0. Willis Index Contributors
1,767 citations