Evaluating body condition in small mammals

2001 ◽  
Vol 79 (6) ◽  
pp. 1021-1029 ◽  
Author(s):  
A I Schulte-Hostedde ◽  
J S Millar ◽  
G J Hickling

Body condition (energy reserves) can have important fitness consequences. Measuring condition of live animals is typically done by regressing body mass on measures of body size and using the residuals as an index of condition. The validity of this condition index was evaluated by determining whether it reflected measured fat content of five species of small mammals (yellow-pine chipmunks (Tamias amoenus Allen), bushy-tailed wood rats (Neotoma cinerea Ord), deer mice (Peromyscus maniculatus Ord), red-backed voles (Clethrionomys gapperi Vigors), and meadow voles (Microtus pennsylvanicus Ord)). We also determined whether body water could predict fat content, enabling the use of hydrogen-isotope dilution for estimating condition. For all five species, condition estimates weakly predicted fat content and more accurately predicted variation in lean dry mass and water content. The relationship between body water and fat content was inconsistent among the five species, discouraging against the general use of isotope dilution in these animals. Although ecologically important, these indices are best interpreted as explaining variation in all constituents of body composition.

2001 ◽  
Vol 79 (6) ◽  
pp. 1016-1020 ◽  
Author(s):  
A I Schulte-Hostedde ◽  
J S Millar ◽  
G J Hickling

Differences in reproductive roles between the sexes may lead to sexual dimorphism in body composition. Body size and composition of three species of small mammals (bushy-tailed wood rats (Neotoma cinerea Ord), deer mice (Peromyscus maniculatus Wagner), and red-backed voles (Clethrionomys gapperi Vigors)) were analyzed to test the predictions that (i) males will have more muscle mass than females and (ii) females will have more fat than males. Results supported the first prediction but not the second. For all three species, males had more lean dry mass relative to body size than females, but females did not have relatively more fat than males. Muscle mass of males may aid in mate-searching and mate-guarding activities, but fat content may not differ between the sexes because female small mammals depend on increased ingestion rates, rather than fat stores, to support reproduction.


2003 ◽  
Vol 81 (4) ◽  
pp. 591-595 ◽  
Author(s):  
Albrecht I Schulte-Hostedde ◽  
John S Millar ◽  
Graham J Hickling

Intraspecific variation in testis size is usually interpreted in the context of sperm competition, yet an unconsidered consequence of increased testis size may be an increase in the production of testosterone, which can affect the growth of muscle mass. After muscle mass is corrected for body size, male small mammals have more muscle mass than females, which suggests that it may be a sexually selected trait. An enhanced musculature may have fitness consequences with respect to male mate-searching activities and male–male competition for access to females. We tested the prediction that males with large testes have more muscle mass (measured as lean dry mass) by examining testis size and body composition in three species of small mammals (bushy-tailed wood rat (Neotoma cinerea), deer mouse (Peromyscus maniculatus), and red-backed vole (Clethrionomys gapperi)) from the Kananaskis Valley, Alberta. In all three species, males with relatively large testes had relatively more lean dry mass than males with relatively small testes. This suggests that a secondary consequence of relatively large testes may be a relative increase in muscle mass. Further research should investigate alternative effects of intraspecific variation in testis size on individual fitness within wild populations to gain further insight into sexual selection.


1993 ◽  
Vol 41 (4) ◽  
pp. 317 ◽  
Author(s):  
CJ Krebs ◽  
GR Singleton

Estimates of body condition in mammals may be constructed from measures of skeletal size and body mass. We illustrate the methodology for doing this using data from two populations of feral house mice (Mus domesticus) in Australia, and point out an erroneous method that has commonly been used in the literature. Indices of condition for individual house mice were not correlated with the fat content of their carcasses. Indices of condition for house mice have a relatively low repeatability because of variation from day to day in body mass and because of variation in length measurements taken by different observers. Bias in measurements among observers must be eliminated to make indices of condition from live animals useful.


1997 ◽  
Vol 24 (6) ◽  
pp. 649 ◽  
Author(s):  
Andrew P. Woolnough ◽  
William J. Foley ◽  
Christopher N. Johnson ◽  
Murray Evans

Several indirect methods for measuring body composition in a large herbivore, the southern hairy-nosed wombat (Lasiorhinus latifrons), were evaluated. Body composition was determined by whole-body chemical analysis of 15 wild-caught wombats, and compared with several indices of body fat: total body water measured by isotope dilution, bioelectrical impedance analysis (BIA), body-mass index, and a body- condition score. Total body water and total body fat (by soxhlet analysis) were highly correlated (r2 = 0.97, intercept s.e. = 1.00). Total body water measured by desiccation was highly correlated with isotope dilution space (r2 = 0.97, intercept s.e. = 0.43 for deuterium; r2 = 0.95, intercept s.e. = 0.44 for H218O). Percentage body fat by soxhlet analysis was highly correlated with total body water measured as deuterium dilution space (r2 = 0.83, intercept s.e. = 2.46). Multiple linear regression models using BIA plethysmograph measurements (resistance and impedance) and total body mass, were successful in predicting body fat (r2 = 0.90, s.e. = 1.99) and total body water (r2 = 0.90, s.e. = 1.64). Isotope-dilution techniques are the most accurate means of indirectly measuring total body water and total body fat, but at considerable expense of time and money. BIA offers reduced accuracy but at less cost and may be useful for measuring changes in body composition in populations of herbivores. Body-condition indices and scores correlate poorly with body fat, suggesting that their application as a means to predict body fat is limited.


2019 ◽  
Vol 50 (3) ◽  
pp. 594 ◽  
Author(s):  
Erin M. Newman ◽  
Matthew C. Allender ◽  
Dan Thompson ◽  
Gary A. Glowacki ◽  
Marina Ivančić ◽  
...  

2012 ◽  
Vol 39 (4) ◽  
pp. 301 ◽  
Author(s):  
Gina M. Morgan ◽  
Travis E. Wilcoxen ◽  
Michelle A. Rensel ◽  
Stephan J. Schoech

Context Anthropogenic disturbances induce physiological and behavioural responses in numerous species. The negative effects of human disturbance are of special concern to threatened and endangered species. Aims The present study aims to compare physiological stress measures and reproductive success of Florida scrub-jays (Aphelocoma coerulescens) living near roads with jays that live away from roads. Specifically, it aims to test whether roads are stressful. Methods We assessed physiological measures that can serve as indicators of ‘stress’ to determine whether a highway that bisects our study site had physiological effects on adult male Florida scrub-jays. We captured male breeders from three territory types, including scrub habitat that (1) bordered a highway with a grassy shoulder that created an ‘edge’ habitat (roadside), (2) bordered human-maintained habitat (a plowed firebreak of sand with adjacent pasture) that served as a control for the edge-effect of the road (pasture) and (3) contained only natural scrub habitat (interior). We measured baseline concentrations of the stress hormone corticosterone (CORT), body mass, and a suite of longitudinal body measures to generate a body condition index in males from each territory type over three breeding seasons. Key results Roadside jays had greater body mass than did interior and pasture jays, although there were no differences in overall baseline CORT concentrations or body condition among territory classes. There was no difference in clutch initiation date or size and nestling and independent-young survival. Conclusions Our results suggest that the road through our study site has physiological effects on Florida scrub-jays; however, there is mixed evidence as to whether it acts as a chronic stressor. Implications Our findings provide evidence that roads and road-associated disturbance has neutral or potentially beneficial physiological effects of roads on Florida scrub-jays. Knowledge of these effects of roads and disturbance on jays will hopefully provide additional opportunities to improve conservation of this species.


PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e66399 ◽  
Author(s):  
Nicolas Tête ◽  
Clémentine Fritsch ◽  
Eve Afonso ◽  
Michaël Coeurdassier ◽  
Jean-Claude Lambert ◽  
...  

Author(s):  
Danise Benatti ◽  
Luis Felipe Andrietti ◽  
José Flávio Cândido Júnior ◽  
Alexandre Vogliotti ◽  
Marcela Figueirêdo Duarte Moraes ◽  
...  

Abstract Rodents are small mammals that can be parasitized by various helminths. This study aimed to identify and describe the ecological indicators of infection in rodents captured in fragments of the Atlantic Forest in the western region of Paraná State, Brazil. Sixty-eight specimens of five rodent species were collected, necropsied, and inspected in search of helminths. The parasites were stored in 70% ethanol, morphologically identified, and counted for calculation of infection indicators. Fourteen species of helminths and one species of Crustacea were recorded: ten in Akodon montensis, four in Mus musculus, two in Thaptomys nigrita, two in Oligoryzomys nigripes, and one in Euryoryzomys russatus. The registered species of parasites were: Rodentolepis akodontis, Angiostrongylus sp., Protospirura numidica criceticola, Trichuris navonae, Syphacia alata, Syphacia criceti, Syphacia evaginata, Trichofreitasia lenti, Stilestrongylus aculeata, Stilestrongylus eta, Stilestrongylus gracielae, Stilestrongylus franciscanus, Stilestrongylus moreli, Stilestrongylus sp., and Pentastomida gen. sp. A positive correlation between the intensity of infection of T. navonae and T. lenti was observed with the body condition index of the host A. montensis. For all species, this study represents a new register of locality, and for eight of them a new host.


2016 ◽  
Vol 2 (1) ◽  
pp. 67-76
Author(s):  
Yasser Ahmed ◽  
Armin Fabritzek ◽  
Neviaty P. Zamani ◽  
Karen Von Juterzenka ◽  
Mark Lenz

Pergerakan organisme dipengaruhi oleh penyebaran alami dan aktivitas manusia.Beberapa spesies yang terbawa, memiliki sebaran yang melebihi distribusi batas normal oleh pengaruh tertentu (vector).Penelitian ini melakukan pengujian pada skala laboratorium untuk melihat survival rate yang terkait dengan body condition index selama diberikan stress suhu yang terkait perubahan iklim dan ini juga dapat dijadikan sebagai simulasi transportasi kapal, sehingga dapat diketahui pergerakan organisme.Distribusi organisme tersebut mempengaruhi kemampuan bertahan hidupselama transportasi.Oleh karena itu, perlu dilakukan penelitian dengan mengekspose grup pra-stress dan grup non stress sebelum masuk ke fase stress dan membandingkan survival rate dan body condition index (BCI) pada organisme tersebut. Organisme yang dipilih adalah Kerang Hijau (P. viridis) dengan menggunakan stress suhu.Pengukuran respon variabel dari organisme tersebut yaitu survival rate dan body condition index (BCI).Penelitian ini menunjukkan bahwa survival rate dan body condition index memiliki korelasi linier.


2007 ◽  
Vol 55 (4) ◽  
pp. 249 ◽  
Author(s):  
Louise Mortimer ◽  
Alan Lill

Some birds facing energy ‘bottlenecks’ display elevated oxidative metabolism and oxygen delivery to tissues and could be particularly susceptible to chronic stress. We examined whether there was evidence for such trends in little penguins (Eudyptula minor) over the period from breeding to the post-moulting stage and particularly during the onshore moult-fast. Penguin parents contribute equally to incubation, brooding and brood provisioning. A few weeks post-breeding, adults undergo a protracted, terrestrial moult-fast and then make brief visits to the colony during the post-moulting stage. Provisioning nestling(s) and moulting could theoretically be particularly energetically and nutritionally demanding. We determined for adults whether mass, a body condition index and blood parameters influencing vascular oxygen carrying capacity (hematocrit, Hct; whole blood haemoglobin, Hb) and indicating chronic stress (leukocyte count, WBC; heterophil/lymphocyte ratio, H/L) varied from August to May in a manner reflecting likely variation in energy and nutrient demand. Female mass and body condition index decreased significantly between the incubation and guard stages, before returning to incubation levels between the guard and post-guard nestling stages. Both parameters declined to their lowest levels between the post-guard and moult stages, before increasing to levels comparable with those during nestling care between the moult and post-moult stages. Blood parameters in both sexes exhibited temporal variation similar to that in female mass and body condition index, declining to their lowest levels during moult and increasing after the moult to levels comparable with those during breeding. Results indicated that the period of most intense provisioning of nestlings was associated with a decrease in blood oxygen carrying capacity, but no pronounced change in chronic stress indicators. However, the penguin’s moult-fast involved a loss of female body condition and, in both sexes, a reduction in body mass, vascular oxygen carrying capacity and possibly specific immune competence. Thus, regulation of human disturbance in accessible little penguin colonies may be particularly important during moult.


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