The Allometry of primate skeletal weight

There is a widely held assumption that skeletal weights of mammals increase disproportionately with increased body size. Recent empirical studies have supported this assumption, and it has been suggested that this might account for the fact that metabolic rate scales to body weight with a negative allometry. Other studies, however, have suggested that skeletal weight in primates is directly proportionate to body weight. The results of this study support this latter interpretation and also indicate that the same is true for two other orders of mammals that were a part of the earlier allometric studies. The evidence suggests that skeletal weight scales isometricallywith body weight within individual mammalian orders. From this it is concluded that skeletal weight does not play any part in determining the negatively allometric scaling of metabolic rate.     

Active and resting metabolism in birds: allometry, phylogeny and ecology

Variation in resting metabolic rate is strongly correlated with differences in body weight among birds. The lowest taxonomic level at which most of the variance in resting metabolic rate and body weight is evident for the sample is among families within orders. The allometric exponent across family points is 0.67. This exponent accords with the surface area interpretation of metabolic scaling based on considerations of heat loss. Deviations of family points from this allometric line are used to examine how resting metabolic rates differ among taxa, and whether variation in resting metabolic rate is correlated with broad differences in ecology and behaviour. Despite the strong correlation between resting metabolic rate and body weight, there is evidence for adaptive departures from the allometric line, and possible selective forces are discussed.
The allometric scaling of active metabolic rate is compared with that of resting metabolic rate. The allometric exponents for the two levels of energy expenditure differ, demonstrating that active small-bodied birds require proportionately more energy per unit time above resting levels than do active large-bodied birds. No consistent evidence was found to indicate that the different methods used to estimate active metabolic rate result in systematic bias. Birds require more energy relative to body size when undertaking breeding activities than at other stages of the annual cycle.     

Simplified Resting Metabolic Rate—Predicting Formulas for Normal‐Sized and Obese Individuals

Objective: Resting metabolic rate (RMR) is known to be proportional to body weight and to follow allometric scaling principles. We hypothesized that RMR can be predicted from an allometric formula with weight alone as an independent variable. Research Methods and Procedures: An allometric, power‐law scaling model was fit to RMR measurements obtained from a cohort of patients being treated for weight loss. This, as well as many of the commonly used RMR‐predicting formulas, was tested for RMR prediction ability against a large publicly available RMR database. Bland‐Altman analysis was used to determine the efficacy of the various RMR‐predicting formulas in obese and non‐obese subjects. Results: Power law modeling of the RMR—body weight relationship yielded the following RMR‐predicting equations: RMR_Women = 248 × Weight^0.4356 ? (5.09 × Age) and RMR_Men = 293 × Weight^0.4330 ? (5.92 × Age). Partial correlation analysis revealed that age significantly contributed to RMR variance and was necessary to include in RMR prediction formulas. The James, allometric, and Harris‐Benedict formulas all yielded reasonable RMR predictions for normal sized and obese subjects. Discussion: A simple power formula relating RMR to body weight can be a reasonable RMR estimator for normal‐sized and obese individuals but still requires an age term and separate formulas for men and women for the best possible RMR estimates. The apparent performance of RMR‐predicting formulas is highly dependent on the methodology employed to compare the various formulas.     

The Relation of Energy Metabolism and Body Weight in Bivalves (Mollusca: Bivalvia)

On the basis of experimental and published data, the interspecific and intraspecific (ontogenetic) dependence of energy metabolism on body weight in bivalves was calculated. Changes in the parameters of intraspecific allometric dependence under the effect of environmental factors were analyzed. The rate of comparable standard metabolism (coefficient a at k = 0.76) was shown to vary in different taxonomic and zoogeographic groups of bivalves.     

Growth and oxygen consumption in embryonic and early postembryonic development of European pond turtle <Emphasis Type="Italic">Emys orbicularis</Emphasis> (Reptilia: Emydidae)

Experiments on developing eggs of European pond turtle (Emys orbicularis) demonstrated S-shaped changes in the rate of oxygen consumption and body weight during embryonic development. The rate of oxygen consumption and weight progressively increased within 70 days after hatching. During embryogenesis, the mass-specific rate of oxygen consumption decreased. After hatching, it increased but then decreased to a certain level, which remained constant to the end of the studied period. We observed unidirectional changes in the mass-specific rate of oxygen consumption and specific weight gain during embryonic development and this pattern was maintained after hatching. The coefficients of the allometric relationship between oxygen consumption and body weight were a = 0.33 and k = 0.52 during embryonic development and a = 0.17 and k = 0.89 during postembryonic development.Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 2, 2005, pp. 214–220.Original Russian Text Copyright © 2005 by Vladimirova, Alekseeva, Nechaeva.     

Sample size and mass range effects on the allometric exponent of basal metabolic rate

The controversial relationship between body mass and basal metabolic rate in animals revolves around two questions: what is the allometric scaling exponent and what is the functional basis for it? For mammals, the first question could be resolved if measurements from all 4600 extant species were available, but this study shows that data for only 150 species, spanning three to four orders of magnitude variation in body mass, are sufficient to accurately determine the exponent. Because the currently available data set includes about 600 species that vary over five orders of magnitude in body size, further increases in sample size are unlikely to change the estimate of the scaling exponent.     

Equations describing changes in weight and mass-specific rate of oxygen consumption in animals during postembryonic development

Equations describing growth and respiration rate of animals during postembryonic development have been derived on the basis of thermodynamics of linear irreversible processes. The conditions for equation application are specified as well as the conditions when growth equation can be reduced to the von Bertalanffy equation and when the relationship between the mass-specific rate of oxygen consumption and body weight becomes an allometric relationship.     

Cephalisation bei Caniden

Cephalisation in Canidae Studied were the intraspecific and interspecific relationships between brain weight and body weight in Canidae. Inclination values of the allometric lines: intraspecific – 0,25, interspecific 0,571. Most of the studied species have nearly the same degree of cephalisation, deviations from the interspecific allometric line are small; the cephalisation of Nyctereutes and Otocyon is less developed than in the other canid species. There is no difference in cephalisation between most canids and felids. Mustelids show a high variability in cephalisation. Criticized were the data of Bauchot (1985) and Gittleman (1986) on brain weight and body weight.     

Scaling of follicular sizes in mammalian ovaries

The scaling of ovarian follicle and oocyte sizes according to body weight ( M , ranging from 0005–500 kg) has been analysed using data obtained from 22 mammalian species in nine orders. The diameters of non-growing (primordial) follicles were correlated significantly with body weight, the relationship being described by the allometric formula y = 0028 M ^0.10. The mean size at which growing follicles began to accumulate extracellular fluid was approximately the same in all species, 0–3 mm diameter. Graafian follicle sizes varied allometrically with body weight as a result of differences in the volumes of follicular fluid rather than those of oocytes, which were relatively similar in eutherian mammals. The statistical significance of the correlation between Graafian and body sizes was increased when the dimensions for an ovulatory quota of follicles were combined because follicles in polyovulating species were disproportionately small. The total Graafian surface areas and volumes were then predicted from body weight by 58–4 M ^0.65 and 18–5 M ^1.06, respectively. Follicular dimensions in the three species of primates were significantly greater than predicted by the allometric relationship. The exponents of these relationships show that the total volume of a set of preovulatory follicles varies approximately isometrically with body weight and, therefore, with the presumptive hormone distribution volume ( M ^1.0). The hypoallometric relationship of follicular surface area demonstrates that, during the course of the evolution of body size, the surface area for secretion has not increased to match the dilution of hormones in the body pool.     

Relative growth and sexual dimorphism in the hermit crab Clibanarius signatus Heller, 1861 (Anomura,Diogenidae) from the northern coast of the Persian Gulf,Iran

The purpose of this study was to investigate the relative growth and sexual dimorphism in the hermit crab Clibanarius signatus. The evaluation was done with 955 specimens (494 males, 251 females, and 210 intersexes) captured in Persian Gulf (Iran) during January to December 2015. Animals were submitted to measurements related to weight (BW, total wet weight) and body size related to cephalic shield (SW, width; and SL, length) and propodus of both chelipeds (CPL, length; and CPW, width). Males were larger and heavier than females and intersexes. Both males and females showed a negative allometric growth for the SL–BW and SL–SW relationships, but a positive allometric growth to intersex specimens. To SL–CPL relationship, a negative allometric growth was confirmed in males and females independent of the laterality of the CPL, whereas a contrast was verified in intersexes, with a positive allometric growth occurred for both hands. To SL–CPW relationship, a negative allometric growth (b < 1) occurred in females, independent of the laterality of the CPW, while in males, a positive allometric pattern was confirmed. In intersexes, this relationship was positive except for the right CPW which was isometric. Sexual dimorphism was evident in Clibanarius signatus, with males being the largest and females the smallest specimens in the population.     

Within-species brain-body weight variability: A reexamination of the Danish data and other primate species

A restudy of the Danish brain weight data published by Pakkenberg and Voigt ('64), using partial correlation techniques, confirms and extends their earlier conclusions regarding a much stronger allometric relationship between height and brain weight than between body weight and brain weight. The relationship is particularly strong in males, and not in females, which is hypothesized to be related to higher fat components in the latter. Comparative data for smaller samples of Pan, Gorilla, Pongo, Macaca, Papio, and Saimiri using body weights, suggest that such relationship also hold more strongly in males than females, although more reliable data are greatly needed. In addition to providing within-species ranges of variability for variously derived neural statistics (e.g., encephalization quotients, “extra neurons,” etc.), for “normal” primates, it is suggested that while allometric trends do exist within species, and particularly males, evolutionary pressures leading to larger brain size were probably very diverse, and that any one homogenistic theory is unlikely.     

Direct and correlated responses to artificial selection on lipid and glycogen contents in Drosophila melanogaster

A large outbred population of Drosophila melanogaster was subjected to artificial selection on lipid and glycogen storage. In three separate experiments, two replicates underwent sib selection for both increased and decreased storage. In the first study, flies were selected on the basis of total triacylglycerol for ten generations. This experiment resulted in no significant direct response, but there was a significant change in total body weight, underscoring the importance of concern for the allometric relationship between body weight and lipid content. In the second study, selection was performed for 15 generations on the percentage of body composition that was triacylglycerol. A significant direct response was obtained, and the two replicates revealed heritability estimates of 0.40 and 0.43. The third study selected glycogen content for 15 generations, and produced a significant response with heritabilities of 0.25 and 0.31. A series of 12 biochemical and enzyme kinetic traits was examined at five generation intervals in all experiments, and a number of correlated responses were detected. The results are interpreted with respect to the evolutionary constraints on energy storage evolution and the genetic basis of the allometric relationship between body weight and fat content.     

Differential growth of crayfish Procambarus alleni in relation to hydrological conditions in marl prairie wetlands of Everglades National Park, USA

Environmental conditions influence crustacean growth by affecting molt intervals and incremental increases in length and weight. In the seasonally-flooded marl prairie wetlands of eastern Everglades National Park, U.S.A., hydropattern exerts considerable influence on aquatic primary productivity, and so may influence the availability of food resources for higher trophic levels. The seasonal hydroperiod has been drastically altered by anthropogenic factors, but the impacts on the aquatic community are not well known. We studied whether differences in growth of crayfish Procambarus alleni could be detected in habitats with different hydroperiods. We first described growth patterns based on incremental increases in length and weight of crayfish on a high protein diet in the laboratory. Regression analyses indicated that growth patterns in males and females were similar. Although the intermolt period increased with age, the proportional increases in length and weight were similar through successive molts. The relationship between length and weight of crayfish was best described by a power equation for allometric growth. We then compared growth curves for crayfish subpopulations from different areas of the marl prairie. In habitats with the longest hydroperiods, crayfish weight-at-size was not significantly different from that in laboratory crayfish on the high protein diet. However, weight gain per unit increase in length in short hydroperiod sites was significantly less than in long hydroperiod sites or in the laboratory. These results indicate that crayfish productivity may be associated with hydroperiod in these stressed wetlands, and this may contribute to observed source-sink population regulation.     

The intrinsic rates of increase of insects of different sizes

ABSTRACT.

• 1 A negative relationship between intrinsic rate of increase, r, and body size has only clearly been shown using data for species drawn from a number of phyla and covering several orders of magnitude in size. Analyses for more closely related species are equivocal.
• 2 Data for ninety-one species of insects, from nine orders, were used to examine the correlation between intrinsic rate of increase and size.
• 3 Intrinsic rate of increase was negatively correlated with both length and weight across orders, but no relationship could be shown within orders.
• 4 Generation times were positively related to body size, but there was no relationship between net reproductive rate (R_Q) and size.
• 5 These results support the hypothesis that documented relationships between species size and colonization success in insects could be a consequence of the scaling of intrinsic rate of increase with size.

     

ARTIFICIAL SELECTION ON HORN LENGTH-BODY SIZE ALLOMETRY IN THE HORNED BEETLE ONTHOPHAGUS ACUMINATUS (COLEOPTERA: SCARABAEIDAE)

Males of the horned beetle Onthophagus acuminatus Har. (Coleoptera: Scarabaeidae) exhibit horn length dimorphism due to a sigmoidal allometric relationship between horn length and body size: the steep slope of the allometry around the inflection of the sigmoid curve separates males into two groups; those larger than this inflection possess long horns, and those smaller than this inflection have short horns or lack horns. I examined the genetic basis of the allometric relationship between horn length and body size by selecting males that produced unusually long horns, and males that produced unusually short horns, for their respective body sizes. After seven generations of selection, lines selected for relatively long horns had significantly longer horn lengths for a given body size than lines selected for relatively short horns, indicating a heritable component to variation in the allometry. The sigmoidal shape of the allometry was not affected by this selection regime. Rather, selected lines differed in the position of the allometry along the body size axis. One consequence of lateral shifts in this allometric relationship was that the body size separating horned from hornless males (the point of inflection of the sigmoid curve) differed between selection lines: lines in which males were selected for relatively long horns began horn production at smaller body sizes than lines selected for relatively short horns. These results suggest that populations can evolve in response to selection on male horn length through modification of the growth relationship between horn length and body size.     

Length–weight relationship and condition factor of Lepidocephalichthys goalparensis Pillai and Yazdani, 1976 in Assam,India

The present study describes the length–weight relationship (LWR), condition factor (K) and size at first maturity of a cobitid loach, Lepidocephalichthys goalparensis Pillai and Yazdani, 1976 of the family Cobitidae in Assam, India. A total of 716 specimens (males = 324, females = 392) ranging from 3.06 to 7.01 cm total length (TL) and 0.17–2.27 g body weight (BW) were analyzed. The overall value of the allometric coefficient b for the LWR indicated negative allometric growth (<3.00) for both males (2.774) and females (2.993). The size at first maturity (TL₅₀) for female L. goalparensis was estimated to be 5.6 cm TL. The condition factor values ranged from 0.56 to 1.35 in mature females. This is the first time that the biological parameters have been studied in this species.     

Allometry and variability of resource allocation to reproduction in a wild reindeer population

The differential allocation of energy to either reproductionor survival represents a major conflict with important implicationsfor patterns of life history. Here, we explore how covariationbetween maternal body weight and fetal weight vary accordingto fetal sex in a wild reindeer (Rangifer tarandus) populationduring two contrasting years. Maternal weights differed duringthe 2 years, probably because of a difference in populationdensity. We could not detect any change in the allocation toreproduction depending on female phenotypic distribution. Malefetuses were heavier than female fetuses, with the same relativedimorphism in both years. There was no support for a correlationbetween the sex of the fetus carried by a female and her weight.Our results suggest that the level of resource allocation toreproduction during the prenatal period is strongly determinedby female body weight and the allometric relationship betweenbody weight and metabolic rate. We discuss the consequencesof our results for population dynamics. We call for an integrationof inter- and intraspecific allometric approaches to betterunderstand constraints and variation in life-history traits.     

Estimating consumable biomass from body length and order in insects and spiders

1. Current models used to estimate insect prey biomass for diet studies use whole weight. However, a large proportion of an arthropod's body is taken up by an indigestible exoskeleton, leading to erroneous estimation of the food intake of insectivorous animals. 2. Linear mixed effect models were used to obtain equations to predict consumable biomass from body length for a variety of Neotropical insects and spiders. These data were obtained by feeding taxa of various orders to groups of 100 social spiders and comparing pre‐ and post‐consumption weights using size‐matched controls. 3. Significant linear relationships were found relating body size to consumed biomass for all orders, with slopes ranging from 1.276 to 4.011 and R² values from 0.476 to 0.929. For orders other than spiders and Orthoptera, the increase in weight with size exhibited negative allometric scaling, suggesting a decrease in tissue density, or an increase in internal air space, with size. 4. Although there were significant differences across taxonomic orders in the proportion of biomass consumed, within most orders the proportion consumed did not differ significantly with body size. The estimated regression coefficients may be used by other workers to estimate consumable biomass of arthropod prey for studies requiring large sample sizes or non‐lethal sampling of rare or endangered species.     

Postembryonal morphological variation of <Emphasis Type="Italic">Daphnia galeata</Emphasis> in water bodies of different types

Despite many ecological studies the population morphological variability within the freshwater crustacean genus Daphnia is poorly investigated, especially during postembryonic development. Unusual phenotypic plasticity of some Daphnia species results in tremendous difficulties in morphological species delineation. The ontogenetic morphological variation of this species was studied, revealing the general trends in body shape variation in different populations. The morphotypes of size and age groups of D. galeata turned out to be more variable at the mouth of the Kargat River (Lake Chany basin) than in Lake Todzha (Bol’ shoi Yenisei River basin); however, the growth of characters such as the helmet and tail spine was described by an allometric function and their absolute sizes decreased with age in Daphnia from both water basins. It is shown that the first mature size-and-age group of D. galeata is most suitable for investigating population morphological variation.     

Protein, lipid, water and caloric contents of immature rainbow trout, Salmo gairdneri Richardson, growing at different rates

Protein, lipid, water and caloric contents of immature rainbow trout, relative to size of whole fish, growing at different rates were examined by use of allometric analysis (y = ax^b, Huxley, 1932). Fish grew at different rates as a result of differences in ration size (satiation, or 4–5% of dry body weight), temperature (7 and 12°C) and bGH (bovine growth hormone) administration. In fingerlings, protein, lipid and caloric contents tended to increase (v. body weight) as a percentage of body composition, whereas above fingerling size, protein decreased while lipid and caloric contents still increased. These trends occurred regardless of growth rate differences. The correlations between protein, lipid, caloric contents and body weight were high so reliable estimates of body components can be made from body weight for all experimental treatments. At satiation rations (7 and 12°C), there were no significant differences in protein content, but lipid and caloric contents were significantly higher in control fish. At low rations, protein and caloric contents were lower than those at satiation rations and lipid was lower than in the control group. On a dry weight basis, in uninjected fish at 12°C, ration size did not influence the percentage composition (protein and lipid) but the low ration group had lower energy values per unit of body dry weight. At low temperature (7°C satiation), fish had lower lipid and higher protein content (dry weight basis) than their controls (12°C satiation), thereby resembling bGH injected fish at satiation rations. Values of caloric content estimated from protein and lipid values by use of standard conversion factors differed sufficiently from caloric values directly determined by bomb calorimetry to suggest that caloric values of lipids may change during growth. The increase in body caloric content during growth apparently results mainly from an increase in the percentage of lipid. The similarity of body composition between different growth rate groups implied a tendency for conservation of relative proportions of components such that body composition can be approximated from body weight. Equations were also given to describe the relationship between water content and body constituents, and the relationship between condition factor (K) and both the body dry weight and lipid content.