Modelling the nutritional ecology of ungulate herbivores: evolution of body size and competitive interactions

Oecologia ◽  
1992 ◽  
Vol 89 (3) ◽  
pp. 428-434 ◽  
Author(s):  
A. W. Illius ◽  
I. J. Gordon
Keyword(s):  
Body Size ◽  
Nutritional Ecology ◽  
Competitive Interactions

scholarly journals Nutritional ecology provides insights into competitive interactions between closely-related marten species

2019 ◽  
Author(s):  
Andrea Gazzola ◽  
Alessandro Balestrieri
Keyword(s):  
Interspecific Competition ◽  
Food Item ◽  
Resource Competition ◽  
Feeding Habits ◽  
Nutritional Ecology ◽  
Metabolizable Energy ◽  
Competitive Interactions ◽  
Stone Marten ◽  
Pine Marten ◽  
Nutrient Profiles

AbstractFor generalist, closely-related predators as those belonging to the genusMartes, it is a hard task to differentiate the effects on feeding habits of variation in food availability from those of resource competition. To overcome this obstacle, we reviewed dietary studies that assessed the relative bulk of each food item, as either percent biomass or percent mean volume, in the diet of both the pine-(M. martes) and stone-(M. foina) marten, and calculated the nutrient profiles (intakes of protein, lipids and carbohydrates, expressed as percentages of total metabolizable energy) of each diet. Both martens’ diets tightly clustered (average values: 47% protein-, 39% lipid- and 14% carbohydrate energy), but, most interestingly, in allopatry the nutritional niches of the two species did not differ, while the stone marten ate more carbohydrates and less protein when sympatric with the pine marten. Our data suggest that stone marten frugivory is the result of interspecific competition.

scholarly journals Food Web Structure Informs Potential Causes of Bimodal Size Structure in a Top Predator

2018 ◽  
Vol 11 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Peter C. Searle ◽  
Joshua A. Verde ◽  
Mark C. Belk
Keyword(s):  
Body Size ◽  
Yellow Perch ◽  
Lake Trout ◽  
Large Body ◽  
Somatic Growth ◽  
Salvelinus Namaycush ◽  
Trophic Niche ◽  
Competitive Interactions ◽  
Large Body Size ◽  
Small Lake

Background: Assemblages of fishes in lakes and reservoirs in the western USA are dominated by non-native, large-bodied, piscivorous fishes that lack a shared evolutionary history. Top predators in these crowded systems are often characterized by unstable population dynamics and poor somatic growth rates. One such assemblage is in Fish Lake, located in southern Utah, USA, in which introduced lake trout (Salvelinus namaycush, Walbaum) exhibit a bimodal growth pattern. A few lake trout in Fish Lake grow rapidly to large size typical of the species; whereas, most never grow beyond 600 mm total length. Objective: To inform competitive interactions in this evolutionarily novel fish assemblage that might cause the low recruitment to large body size in lake trout, we characterized trophic niche (from stable isotope analysis of C and N) of all fishes in the lake. Methods: We used a Bayesian mixing model to describe the trophic niche and infer diet of lake trout and their potential prey, and we used Bayesian ellipse analysis to identify potential areas of high competition within the food web. Large lake trout feed mostly on small lake trout and splake (Salvelinus namaycush, Walbaum x Salvelinus fontinalis, Mitchill) despite availability of abundant yellow perch. (Perca flavescens, Mitchill). Small lake trout and splake feed mostly on zooplankton and exhibit substantial overlap of their trophic niche implying competition for food. Yellow perch and Utah chub (Gila atraria, Girard; formerly an important food item for lake trout in Fish Lake) exhibit extreme overlap of their trophic niche implying strong competitive interactions. Results: Our data suggest that lack of recruitment to large body size in lake trout may result from a reduction in availability of Utah chub resulting from competitive interactions with yellow perch, and increased competition from introduced splake for available prey. Conclusion: Management actions that may help ameliorate the poor somatic growth rates of most lake trout include efforts to reduce perch populations or increase vulnerability of perch to predation by lake trout, and removal of splake as a competitor of small lake trout.

scholarly journals The Role of Body Size and Shape in Understanding Competitive Interactions within a Community of Neotropical Dung Beetles

2011 ◽  
Vol 11 (13) ◽  
pp. 1-14 ◽  
Author(s):  
Malva I. M. Hernández ◽  
Leandro R. Monteiro ◽  
Mario E. Favila
Keyword(s):  
Body Size ◽  
Dung Beetles ◽  
Competitive Interactions ◽  
Size And Shape

scholarly journals The evolution of size-dependent competitive interactions promotes species coexistence

2021 ◽  
Author(s):  
Jaime M Anaya-Rojas ◽  
Ronald D Bassar ◽  
Tomos Potter ◽  
Allison Blanchette ◽  
Shay Callahan ◽  
...  
Keyword(s):  
Body Size ◽  
Interspecific Competition ◽  
Poecilia Reticulata ◽  
Species Coexistence ◽  
Somatic Growth ◽  
Competitive Interactions ◽  
Growth Data ◽  
Sympatric Populations ◽  
Size Dependent ◽  
Niche Shifts

Theory indicates that competing species coexist in a community when intraspecific competition is stronger than interspecific competition. When body size determines the outcome of competitive interactions between individuals, coexistence depends also on how resource use and the ability to compete for these resources change with body size. Testing coexistence theory in size-structured communities, therefore, requires disentangling the effects of size-dependent competitive abilities and niche shifts. Here, we tested the hypothesis that the evolution of species and size-dependent competitive asymmetries increased the likelihood of coexistence between interacting species. We experimentally estimated the effects of size-dependent competitive interactions on somatic growth rates of two interacting fish species, Trinidadian guppies (Poecilia reticulata) and killifish (Rivulus hartii). We controlled for the effects of size-dependent changes in the niche at two competitive settings representing the early (allopatric) and late (sympatric) evolutionary stages of a killifish-guppy community. We fitted the growth data to a model that incorporates species and size-dependent competitive asymmetries to test whether changes in the competitive interactions across stages increased the likelihood of species coexistence from allopatry to sympatry. We found that guppies are competitively superior to killifish but were less so in sympatric populations. The decrease in the effects of interspecific competition on the fitness of killifish and increase in the interspecific effect on guppies` fitness increased the likelihood that sympatric guppies and killifish will coexist. However, while the competitive asymmetries between the species changed consistently between allopatry and sympatry between drainages, the size-dependent competitive asymmetries varied between drainages. These results demonstrate the importance of integrating evolution and trait-based interactions into the research of how species coexistence.

Adolescent Gender Differences in Weight, Activity, and Body-Size Perception

2012 ◽  
Author(s):  
Judith R. Mccalla ◽  
Katie E. Chipungu ◽  
Patrice G. Saab ◽  
Amanda J. Countryman ◽  
Erin N. Etzel ◽  
...  
Keyword(s):  
Gender Differences ◽  
Body Size ◽  
Size Perception ◽  
Body Size Perception
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