Predator–prey size relationships in North American dabbling ducks

1984 ◽  
Vol 62 (10) ◽  
pp. 2002-2008 ◽  
Author(s):  
Thomas D. Nudds ◽  
James N. Bowlby
Keyword(s):  
Prey Size ◽  
Taxonomic Composition ◽  
Size Distributions ◽  
Dabbling Ducks ◽  
Predator Prey ◽  
Caloric Density ◽  
Bill Morphology ◽  
Bill Length ◽  
Niche Dimension ◽  
Solitary Species

Diets of dabbling ducks (Anas: Anatidae) usually have been recorded only with respect to taxonomic composition and not prey size. Interspecific diet overlap thus has been termed large. However, using published taxonomic diet lists for seven species of ducks, measurements of bill morphology from museum specimens, and "handbook" data on the sizes and caloric density of invertebrates, prey size distributions were found to differ among species (P < 0.001). Also, the sizes of prey in each species' diet differed from that found in the environment. The number of lamellae per centimetre of bill negatively correlated with mean prey size (P < 0.001); body size and bill length did not. Based on the similarity of environmental and dietary prey size distributions, species were classified as specialist or generalist foragers. This classification corresponded well with one generated from analyses of foraging behaviour alone. An explanation for the diminuitive sizes of ducks on islands was advanced: if interspecific competition for food selects for niche divergence among coexisting dabbling ducks along a prey size niche dimension, then in the absence of competition from small species on islands, large solitary species have evolved to a smaller size which may be optimal for the distribution of energy among prey size classes in the environment.

Sexual size dimorphism in relation to resource partitioning in North American dabbling ducks

1984 ◽  
Vol 62 (10) ◽  
pp. 2009-2012 ◽  
Author(s):  
Thomas D. Nudds ◽  
Richard M. Kaminski
Keyword(s):  
North American ◽  
Resource Partitioning ◽  
Sexual Size Dimorphism ◽  
Prey Size ◽  
Dabbling Ducks ◽  
Male And Female ◽  
Size Dimorphism ◽  
Bill Morphology ◽  
Size Dimension ◽  
Bill Length

Data from museum specimens were used to examine patterns of sexual size dimorphism in bill morphology in relation to resource partitioning in seven species of North American dabbling ducks (Anas sp.). All species were dimorphic with respect to bill length. Male and female bill length distributions were skewed in opposite directions in five of seven species (P < 0.01). Four of seven species were dimorphic with respect to lamellar density, but male and female distributions were skewed in opposite directions in only two species. The four dimorphic species were positioned between other species along a prey size dimension; species which were not dimorphic had only one neighbour on the prey size dimension. These results are consistent with the hypothesis that intersexual competition for food promotes niche divergence between sexes and contributes to sexual size dimorphism in ducks.

scholarly journals The mechanics of predator–prey interactions: First principles of physics predict predator–prey size ratios

2018 ◽  
Vol 33 (2) ◽  
pp. 323-334 ◽  
Author(s):  
Sébastien M. J. Portalier ◽  
Gregor F. Fussmann ◽  
Michel Loreau ◽  
Mehdi Cherif
Keyword(s):  
First Principles ◽  
Prey Size ◽  
Predator Prey

scholarly journals The impact of large terrestrial carnivores on Pleistocene ecosystems

2015 ◽  
Vol 113 (4) ◽  
pp. 862-867 ◽  
Author(s):  
Blaire Van Valkenburgh ◽  
Matthew W. Hayward ◽  
William J. Ripple ◽  
Carlo Meloro ◽  
V. Louise Roth
Keyword(s):  
Prey Size ◽  
Habitat Degradation ◽  
Terrestrial Ecosystems ◽  
Growth Data ◽  
Predator Prey ◽  
Body Sizes ◽  
Population Sizes ◽  
Potential Impact ◽  
The Impact ◽  
Ground Sloths

Large mammalian terrestrial herbivores, such as elephants, have dramatic effects on the ecosystems they inhabit and at high population densities their environmental impacts can be devastating. Pleistocene terrestrial ecosystems included a much greater diversity of megaherbivores (e.g., mammoths, mastodons, giant ground sloths) and thus a greater potential for widespread habitat degradation if population sizes were not limited. Nevertheless, based on modern observations, it is generally believed that populations of megaherbivores (>800 kg) are largely immune to the effects of predation and this perception has been extended into the Pleistocene. However, as shown here, the species richness of big carnivores was greater in the Pleistocene and many of them were significantly larger than their modern counterparts. Fossil evidence suggests that interspecific competition among carnivores was relatively intense and reveals that some individuals specialized in consuming megaherbivores. To estimate the potential impact of Pleistocene large carnivores, we use both historic and modern data on predator–prey body mass relationships to predict size ranges of their typical and maximum prey when hunting as individuals and in groups. These prey size ranges are then compared with estimates of juvenile and subadult proboscidean body sizes derived from extant elephant growth data. Young proboscideans at their most vulnerable age fall within the predicted prey size ranges of many of the Pleistocene carnivores. Predation on juveniles can have a greater impact on megaherbivores because of their long interbirth intervals, and consequently, we argue that Pleistocene carnivores had the capacity to, and likely did, limit megaherbivore population sizes.

scholarly journals Paleogene community change among terrestrial vertebrates of the Western Hemisphere

1992 ◽  
Vol 6 ◽  
pp. 282-282
Author(s):  
Richard K. Stucky
Keyword(s):  
North America ◽  
South America ◽  
Community Change ◽  
Taxonomic Composition ◽  
Western Hemisphere ◽  
Dental Morphology ◽  
Predator Prey ◽  
Terrestrial Vertebrates ◽  
Morphological Adaptations ◽  
Dinosaur Extinction

Paleogene vertebrate communities in North and South America show dramatic changes in taxonomic composition and ecological organization. Worldwide, mammals diversified substantially following dinosaur extinction (Fig. 1). Most families of living vertebrates appear by the end of the Paleogene. In North America, placental omnivores, herbivores and carnivores dominate mammalian communities, but in South America marsupial carnivores and omnivores and placental herbivores dominate them. Immigration from Asia and Europe to North America of taxa from several placental orders (Perissodactyla, Primates, Artiodactyla, Rodentia, Carnivora, Mesonychia, Creodonta) occurred periodically during the Paleogene. South America, however, was completely isolated from the Paleocene to the Oligocene when Rodentia and perhaps Primates first appear. Despite the independent evolutionary histories of these continents, their constituent species show remarkable convergences in morphological adaptations including body size distributions, dental morphology, and other features. Low resolution chronostratigraphic data for the Paleogene of South America precludes correlation with North American faunas. In North America, patterns of diversification and extinction appear to be related to climatic events. Morphological convergences appear to be related to climate and concomitant habitat change, but may also be a function of coevolution via predator-prey interactions and diffuse competition among guild members.

Feeding Habits and Predator-Prey Size Relationships in the Whiptail LizardCnemidophorus ocellifer(Teiidae) in the Semiarid Region of Brazil

2012 ◽  
Vol 7 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Raul F. D. Sales ◽  
Leonardo B. Ribeiro ◽  
Jaqueiuto S. Jorge ◽  
Eliza M. X. Freire
Keyword(s):  
Prey Size ◽  
Feeding Habits ◽  
Semiarid Region ◽  
Predator Prey

The direct and indirect effects of temperature on a predator–prey relationship

2001 ◽  
Vol 79 (10) ◽  
pp. 1834-1841 ◽  
Author(s):  
Michael T Anderson ◽  
Joseph M Kiesecker ◽  
Douglas P Chivers ◽  
Andrew R Blaustein
Keyword(s):  
Indirect Effects ◽  
Prey Capture ◽  
Prey Size ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Predator Prey ◽  
Prey Mass ◽  
Effects Of Temperature ◽  
Logistic Regression Equation ◽  
Probability Of Capture

Abiotic factors may directly influence community structure by influencing biotic interactions. In aquatic systems, where gape-limited predators are common, abiotic factors that influence organisms' growth rates potentially mediate predator–prey interactions indirectly through effects on prey size. We tested the hypothesis that temperature influences interactions between aquatic size-limited insect predators (Notonecta kirbyi) and their larval anuran prey (Hyla regilla) beyond its indirect effect on prey size. Notonecta kirbyi and H. regilla were raised and tested in predator–prey trials at one of three experimentally maintained temperatures, 9.9, 20.7, or 25.7°C. Temperature strongly influenced anuran growth and predator success; mean tadpole mass over time was positively related to temperature, while the number of prey caught was negatively related. At higher temperatures tadpoles attained greater mass more quickly, allowing them to avoid capture by notonectids. However, the probability of capture is a function of both mass and temperature; temperature was a significant explanatory variable in a logistic regression equation predicting prey capture. For a given prey mass, tadpoles raised in warmer water experienced a higher probability of capture by notonectids. Thus, rather than being static, prey size refugia are influenced directly by abiotic factors, in this case temperature. This suggests that temperature exerts differential effects on notonectid and larval anurans, leading to differences in the probability of prey capture for a given prey mass. Therefore, temperature can influence predator–prey interactions via indirect effects on prey size and direct effects on prey.

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