Testing models of biological scaling with mammalian population densities

2003 ◽  
Vol 81 (5) ◽  
pp. 844-851 ◽  
Author(s):  
F Stephen Dobson ◽  
Bertram Zinner ◽  
Marina Silva
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Mammalian Species ◽  
Fractal Dimensions ◽  
Scaling Exponent ◽  
Population Densities ◽  
Biological Variables ◽  
Terrestrial Habitats ◽  
Broad Variety ◽  
The Relationship

Two hypotheses have been suggested to explain the form of interspecific scaling of organismal characteristics to body size, such as the well-known increase in total metabolism with body mass. A hypothesis based on simple Euclidean geometry suggests that the scaling of many biological variables to body size should have a scaling exponent of 2/3, or [Formula: see text]0.667. On the other hand, according to a hypothesis based on fractal dimensions, the relationship between biological variables and body mass should have a scaling exponent of 0.750. We conducted a power analysis of the predicted exponents of scaling under the Euclidean and fractal hypotheses, using average adult body masses and population densities collected from the published literature on mammalian species. The collected data reflect 987 mammal populations from a broad variety of terrestrial habitats. Using statistical methods we determined the sample sizes required to decide between the values of the scaling exponent of the density-to-mass relationship based on the Euclidean (–0.667) and fractal (–0.750) hypotheses. Non-linearities in the dataset and insufficient power plagued our tests of the predictions. We found that mammalian species weighing less than 100 kg had a linear scaling pattern, sufficient power to reveal a difference between the scaling coefficients –0.667 and –0.750, and an actual scaling coefficient of –0.719 (barely significantly different from –0.667 but not from –0.750). Thus, our results support the fractal hypothesis, though the support was not particularly strong, which suggests that the relationship between body mass and population density should have a scaling exponent of –0.750.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

The Relationship between Body Mass Index and Body Size Dissatisfaction in Young Adolescents: Spline Function Analysis

2010 ◽  
Vol 110 (7) ◽  
pp. 1098-1102 ◽  
Author(s):  
Samuele Cortese ◽  
Bruno Falissard ◽  
Yolande Pigaiani ◽  
Claudia Banzato ◽  
Giovanna Bogoni ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Size ◽  
Body Mass ◽  
Spline Function ◽  
Function Analysis ◽  
Young Adolescents ◽  
Body Size Dissatisfaction ◽  
The Relationship

Size Matters: Body Size is Correlated with Longevity in Speckled Cockroaches (Nauphoeta cineria).

2021 ◽  
Vol 14 ◽  
Author(s):  
Sami Badwan ◽  
James Harper
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Body Length ◽  
Individual Species ◽  
Time Of Death ◽  
Large Size ◽  
The Status ◽  
Males And Females ◽  
The Relationship ◽  
Individual Body

Background: A relationship between body size and longevity has long been appreciated within eukaryotes, especially vertebrates. Introduction: In general, large size is associated with increased longevity among species of mammals and birds but is associated with decreased longevity within individual species such as dogs and mice. In this study, we examined the relationship between measures of individual body size and longevity in a captive population of speckled cockroaches (Nauphoeta cineria). Method: Newly molted adults of both sexes were removed from a mass colony housed in multiple terraria and housed individually with food and water provided ad libitum for the duration of their lifespan. Thrice weekly, the status (i.e. live/dead) of individual cockroaches was noted for the duration of the study. Individuals found dead were weighed and measured to obtain body mass and morphometric measures and the age at the time of death was recorded. The relationship between body size and lifespan was assessed. Result: Contrary to what is commonly seen within vertebrates, large cockroaches were longer-lived than their smaller counterparts. Specifically, body mass, body length and pronotum width were all significantly correlated with the age at death in a mixed population of males and females (n = 94). In addition, we found that the longevity of a historically larger population in terms of both body mass and body length were significantly longer-lived than the population used in this study. Conclusion: These data indicate there is a significant interaction between body size and aging in this species and that increased size results in a survival advantage. There is evidence in the literature indicating that a positive relationship between size and longevity may be common in insects.

The influence of body size on measurements of overall cardiac function

2005 ◽  
Vol 289 (5) ◽  
pp. H2059-H2065 ◽  
Author(s):  
Paul D. Chantler ◽  
R. E. Clements ◽  
L. Sharp ◽  
K. P. George ◽  
L.-B. Tan ◽  
...  
Keyword(s):  
Body Size ◽  
Cardiac Function ◽  
Body Mass ◽  
Scaling Exponent ◽  
Allometric Model ◽  
Physiological Variable ◽  
Men And Women ◽  
Cardiac Power ◽  
Age Range ◽  
Separate Regression

The purpose of this study was to determine the best scaling method to account for the effects of body size on measurements of overall cardiac function and subsequently the interpretation of data based on cardiac power output (CPO). CPO was measured at rest (CPOrest) and at maximal exercise (CPOmax) on 88 and 103 healthy but untrained men and women, respectively, over the age range of 20–70 yr. Cardiac reserve (CR) was calculated as CPOmax − CPOrest. CPOrest, CPOmax, and CR were all significantly related to body mass (BM), body surface area (BSA), and lean body mass (LBM). The linear regression model failed to completely normalize these measurements. In contrast, the allometric model produced size-independent values of CPO. Furthermore, all the assumptions associated with the allometric model were achieved. For CPOrest, mean body size exponents were BM0.33, BSA0.60, and LBM0.47. For CPOmax, the exponents were BM0.41, BSA0.81, and LBM0.71. For CR, mean body size exponents were BM0.44, BSA0.87, and LBM0.79. LBM was identified (from the root-mean-squares errors of the separate regression models) as the best physiological variable (based on its high metabolic activity) to be scaled in the allometric model. Scaling of CPO to LBM b (where b is the scaling exponent) dramatically reduced the between-gender differences with only a 7% difference in CPOrest and CPOmax values. In addition, the gender difference in CR was completely removed. To avoid erroneous interpretations and conclusions being made when comparing data between men and women of different ages, the allometric scaling of CPO to LBM b would seem crucial.

The Relationship Between Perceived and Ideal Body Size and Body Mass Index in 3rd-Grade Low Socioeconomic Hispanic Children

2005 ◽  
Vol 21 (4) ◽  
pp. 224-228 ◽  
Author(s):  
Allison Fisher ◽  
Mary Anne Lange ◽  
Virginia Young-Cureton ◽  
Daryl Canham
Keyword(s):  
Body Mass Index ◽  
Body Size ◽  
Body Mass ◽  
Body Satisfaction ◽  
Healthy Weight ◽  
Ideal Self ◽  
Body Images ◽  
Low Socioeconomic ◽  
Self Image ◽  
The Relationship

Very little is known about body satisfaction among minority children. This study examined the relationship between perceived and actual body size and Body Mass Index among 43 low-socioeconomic Hispanic 3rd-graders. Researchers measured participants’ Body Mass Index; students self-reported Perceived Ideal Self Image and Perceived Actual Self Image using Collins’ (1991) pictorial instrument scale of seven child body images that illustrate body weight from very thin to obese. The majority of students chose body images from the scale that depicted a healthy weight for both their Perceived Ideal Self Image and Perceived Actual Self Image. More boys than girls chose underweight as their Perceived Ideal Self Image. Thirty percent of the students were found to be overweight and 30 percent were at risk for being overweight. A small positive correlation between Perceived Actual Self Image and Body Mass Index was found.

Does size matter? The effects of body size and declining oxygen tension on oxygen uptake in gastropods

2011 ◽  
Vol 92 (7) ◽  
pp. 1603-1617 ◽  
Author(s):  
Islay D. Marsden ◽  
Sandra E. Shumway ◽  
Dianna K. Padilla
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Oxygen Uptake ◽  
Body Mass ◽  
Food Type ◽  
Scaling Exponent ◽  
Physiological Variables ◽  
Tissue Weight ◽  
Oxygen Conditions ◽  
Size Matter

Metabolic rate is one of the most frequently measured physiological variables and the relationship between oxygen uptake and body mass is one of the most controversial issues in biology. The present study used closed chamber respirometry to compare the oxygen uptake of 32 species of benthic British gastropod molluscs of a wide size-range (from less than 0.001 g to greater than 10 g dry tissue weight). We investigated the effects of body size on the respiratory rate at 10°C to explore the evolutionary and phylogenetically determined patterns of metabolic scaling both among different gastropods groups, and within siphonate and asiphonate caenogastropods. Resting oxygen uptake (O2) increased with body mass (W) with a slope value of 0.6 using both ordinary least squares (OLS) and standard major axis (SMA) where N = 488, over a 6 fold range of body mass. The slopes b of the regression lines relating oxygen uptake to body mass were similar for all heterobranch molluscs and most caenogastropods. Highest mass-specific rates for oxygen consumption were found for the smallest littorinid species. Trophic mode significantly affected the amount of oxygen consumed with higher oxygen uptake in herbivores than other groups, including detritivores and predators. All of the gastropods reduced their oxygen consumption when exposed to declining oxygen conditions; however, about a third of the species exhibited partial regulation at higher oxygen partial pressures. When exposed to 20% normal saturation levels, smaller gastropods respired at approximately 25% of their rates in fully saturated seawater whereas larger species (above 0.1 g dry tissue weight) respired at approximately 35% of the values recorded at full saturation. Our study suggests that a scaling exponent relating O2 to body mass of 0.6 is typical and may be ‘universal’ for gastropods. It is below the 0.75 scaling exponent which has been proposed for ectothermic invertebrates. It is concluded that size does matter in determining the metabolic patterns of gastropods and that the quantity of oxygen consumed and the energy balance of gastropods is affected by activity, food type and exposure to declining oxygen conditions.

The influence of habitat on body size and tooth wear in Scottish red deer (Cervus elaphus)

2015 ◽  
Vol 93 (1) ◽  
pp. 61-70 ◽  
Author(s):  
F.J. Pérez-Barbería ◽  
S.L. Ramsay ◽  
R.J. Hooper ◽  
E. Pérez-Fernández ◽  
A.H.J. Robertson ◽  
...  
Keyword(s):  
Body Size ◽  
Cervus Elaphus ◽  
Red Deer ◽  
Mammalian Species ◽  
Tooth Wear ◽  
Fitness Consequences ◽  
Habitat Differences ◽  
Mineral Components ◽  
Mandible Length ◽  
The Relationship

Body size has profound implications for ecology and life-history traits of mammalian species. Tooth wear is an indicator of food-processing investment and diet properties, with fitness consequences through differences in comminution efficiency, nutrient gain, and senescence. We investigate the relationships between mandible length (a proxy of skeletal body size), molar dentine thickness (a measure of tooth wear), and faecal neutral detergent fibre with residual ash (NDF–ash, a combined proxy of fibre and mineral components in the diet) in 874 male and female red deer (Cervus elaphus L., 1758) from 21 locations in moorland and woodland habitats across Scotland. Significant differences in mandible length occurred between habitats: woodland deer having larger mandibles than moorland deer. Within habitats, larger mandibles were related to higher rates of dentine wear, suggesting increased body size was associated with greater intake and processing of food. Both dentine wear and faecal NDF–ash were higher in moorland deer than in woodland deer, suggesting that fibre and (or) mineral abrasives in the diet may have contributed towards habitat differences in dentine wear. Between habitats, higher dentine wear was not associated with larger mandibles, in contrast to the relationship within habitats, indicating the precedence of additional environmental factors between habitats.

scholarly journals Scaling of movements with body mass in a small opossum: evidence for an optimal body size in mammals

2019 ◽  
Vol 100 (6) ◽  
pp. 1765-1773
Author(s):  
Marcus V Vieira ◽  
Diogo Loretto ◽  
Bernardo Papi
Keyword(s):  
Body Size ◽  
Home Range ◽  
Body Mass ◽  
Rio De Janeiro ◽  
Linear Models ◽  
General Pattern ◽  
Information Criteria ◽  
Scaling Exponent ◽  
Minimum Convex Polygon ◽  
Day Range

Abstract Movement by mammals generally increases with body size, described by a positive exponent scaling with either home range area or day range distances. Below ca. 100 g, however, interspecific comparisons suggest a negative scaling, increasing movement with decreasing body size. Such a pattern is expected from the rising costs of thermoregulation below ca. 100 g, implying that it should also be observed in intraspecific comparisons. We tested this hypothesis by investigating the scaling exponent of daily home range with body mass for a small (< 100 g) marsupial, the gray slender mouse opossum, Marmosops incanus. We tracked 85 opossums (56 M, 29 F) with a spool-and-line device between August 1998 and October 2005 in the Serra dos Órgãos National Park, a region of Atlantic Forest in the State of Rio de Janeiro, Brazil. Individual paths were mapped and daily home ranges quantified by the minimum convex polygon encompassing each path. We formulated linear models and compared them using Akaike information criteria. The best-supported model for females had only climatic season as a main determinant of daily home range, whereas the best model for males had body mass and reproductive season as the main effects. As predicted, the scaling exponent of daily home range with body mass of males was negative, in contrast with positive intraspecific exponents for opossums > 100 g estimated in a previous study. The inversion in scaling relationships around 100 g in opossums supports the rising costs of thermoregulation as the main cause of this general pattern in mammals. Effects of body mass are generally weak in intraspecific comparisons, but might still be detected after standardizing other effects, opening new possibilities for testing macroecological models at smaller scales. Espera-se que a quantidade de movimento de mamíferos aumente com o tamanho corporal, descrita por um expoente de escala positivo, tanto para área de vida quanto para distâncias diárias de deslocamento. Abaixo de ca. 100 g, comparações interespecíficas sugerem um expoente negativo, áreas de movimento aumentando com menores tamanhos de corpo. Este padrão é apoiado pelo custo crescente de termorregulação abaixo de ca. 100 g, que implica que também ocorreria em comparações intraespecíficas. Testamos esta hipótese investigando o expoente de escala da área de vida diária com a massa corporal em um pequeno (< 100 g) marsupial, Marmosops incanus. Indivíduos foram rastreados com carretel-de-rastreamento entre agosto de 1998 e outubro de 2005, no Parque Nacional da Serra dos Órgãos, uma região de Mata Atlântica no Estado do Rio de Janeiro, Brasil. Trajetórias individuais foram mapeadas e sua área de vida diária medida pelo polígono convexo mínimo envolvendo cada trajetória. Oitenta e cinco indivíduos foram rastreados, sendo 29 fêmeas e 56 machos. Modelos lineares foram formulados e comparados com o Critério de Informação de Akaike. O modelo com maior suporte para fêmeas teve apenas estação climática como determinante principal da área de vida diária, enquanto o melhor modelo para machos teve massa corporal e estação reprodutiva como efeitos principais. O expoente de escala de área de vida diária com massa corporal de machos foi negativo, contrastando como os expoentes positivos para marsupiais > 100 g estimados em um estudo anterior. A inversão de relações de escala em torno de 100 g nestes marsupiais apoia que custos crescentes de termorregulação sejam a causa principal deste padrão geral em mamíferos. Os efeitos da massa corporal são geralmente fracos em comparações intraespecíficas, mas podem ser detectados após a exclusão de outros efeitos, abrindo novas possibilidades para testar modelos macroecológicos em escalas menores.

Host body size and the abundance of chewing lice (Phthiraptera: Amblycera, Ischnocera) infesting eight owl species (Aves: Strigiformes) in Manitoba, Canada

2019 ◽  
Vol 151 (5) ◽  
pp. 621-628 ◽  
Author(s):  
Robert J. Lamb ◽  
Terry D. Galloway
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Louse Infestation ◽  
Mean Intensity ◽  
Chewing Lice ◽  
Host Body ◽  
Abundant Genus ◽  
Louse Species ◽  
The Relationship ◽  
Host Body Mass

AbstractSpecimens (n = 508) of eight species of owl (Aves: Strigiformes) collected from 1994 to 2017 in Manitoba, Canada, were weighed and examined for chewing lice (Phthiraptera: Amblycera, Ischnocera). The relationship between host body mass and infestation by 12 species of lice was examined. Host body mass explained 52% (P = 0.03) of the variation in mean intensity of louse infestation among hosts, due primarily to a high abundance of lice on the heaviest owl species. The relationship was due to the mean intensity of lice, and neither species richness nor the prevalence of lice was related to host body mass. For individual louse species, the relationship was due primarily to Kurodaia acadicae Price and Beer, Kurodaia magna Emerson, and an undetermined species of Kurodaia Uchida (Phthiraptera: Menoponidae) (R2 = 0.997), but not the nine Strigiphilus Mjöberg (Phthiraptera: Philopteridae) species (R2 = 0.27). Louse intensity did not increase with body size for individual birds of any of the owl species. Mean intensity is expected to increase in proportion with the size, specifically the surface area, of the host. Why that relationship holds only for one louse genus, and not for the most abundant genus of lice on owls, and weakly compared with other families of birds, has yet to be determined.

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