Evaluation of morphological indices and total body electrical conductivity to assess body composition in big brown bats

Pearce, Roger D.; O’Shea, Thomas J.; Wunder, Bruce A.

doi:10.3161/150811008x331171

Cited by 29 publications

(22 citation statements)

References 34 publications

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“…Bats were sexed and weighed to the nearest 0.01g (Durascale-100, MyWeigh, Vancouver, BC, Canada), and their forearm length was measured to the nearest 0.05mm. We defined body condition index (BCI) as mass divided by forearm length (Pearce et al, 2008;Reynolds et al, 2009). We classified individuals as adult or youngof-the-year based on ossification of metacarpal-phalangeal joints and evidence of prior reproduction (Davis and Hitchcock, 1965;Racey, 1974).…”

Section: Allmentioning

confidence: 99%

Hibernation energetics of free-ranging little brown bats

Jonasson

Willis

2012

Journal of Experimental Biology

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SUMMARYHibernation physiology and energy expenditure have been relatively well studied in large captive hibernators, especially rodents, but data from smaller, free-ranging hibernators are sparse. We examined variation in the hibernation patterns of free-ranging little brown bats (Myotis lucifugus) using temperature-sensitive radio-transmitters. First, we aimed to test the hypothesis that age, sex and body condition affect expression of torpor and energy expenditure during hibernation. Second, we examined skin temperature to assess whether qualitative differences in the thermal properties of the hibernacula of bats, compared with the burrows of hibernating rodents, might lead to different patterns of torpor and arousal for bats. We also evaluated the impact of carrying transmitters on body condition to help determine the potential impact of telemetry studies. We observed large variation in the duration of torpor bouts within and between individuals but detected no effect of age, sex or body condition on torpor expression or estimates of energy expenditure. We observed the use of shallow torpor in the midst of periodic arousals, which may represent a unique adaptation of bats for conservation of energy during the most costly phase of hibernation. There was no difference in the body condition of hibernating bats outfitted with transmitters compared with that of control bats captured from the same hibernaculum at the same time. This study provides new information on the energetics of hibernation in an underrepresented taxon and baseline data important for understanding how white-nose syndrome, a new disease devastating populations of hibernating bats in North America, may alter the expression of hibernation in affected bats. Supplementary material available online at

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Section: Allmentioning

confidence: 99%

Hibernation energetics of free-ranging little brown bats

Jonasson

Willis

2012

Journal of Experimental Biology

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“…When measured simultaneously, multidimensional indices such as body shape are generally found to be a better predictor of body composition than body mass alone (Woodall 1978, Iverson and Vohs 1982, Johnson et al 1985, Pearce et al 2008. In our study, body mass was the strongest predictor of total body water and significantly influenced lean dry mass and total body fat, whereas body mass index was only significant in estimating percentage of lean dry mass, and body shape was only significant in estimating lean body mass.…”

Section: ) and Mammals (mentioning

confidence: 43%

“…Some nondestructive techniques developed in recent years are potentially as accurate and precise as direct analyses and may be used repeatedly on the same individuals with minimal harm. Among the several nondestructive methods available, total body electrical conductivity (TO-BEC) has been shown to accurately estimate body composition in free-ranging birds, reptiles, and small mammals (Bachman 1994, Froncisz et al 1994, Lukaski et al 1994, Zuercher et al 1997, Angilleta 1999, including bats (Koteja et al 2001, Pearce et al 2008.…”

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confidence: 99%

Evaluation of Total Body Electrical Conductivity to Estimate Body Composition of a Small Mammal

Reynolds¹,

Sullivan

Kunz

2009

J Wildl Manag

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The ability to measure body composition is critical for studying the physiological ecology of animals. This is particularly true for small mammals that have a high metabolic rate. We evaluated a nondestructive method of body composition analysis that would allow accurate assessment of body fat, body water, and lean mass. We used total body electrical conductivity (TOBEC) to estimate body composition in the little brown myotis (Myotis lucifugus). In a sample of 46 individuals, TOBEC was both accurate and precise in estimating total body water and lean mass but was less effective at estimating total body fat. Mass‐independent or whole‐body compartments (i.e., total body water, total body fat, lean dry mass, and lean body mass) were more accurately estimated than mass‐dependent or mass‐specific body composition compartments (i.e., water content, fat index, and % lean dry mass). The TOBEC measurements we made using an SA‐3000 analyzer were influenced by extremes in body temperature, as well as by aluminum and incoloy wing bands. Our study also presents a new method of restraint especially suited for small mammals and birds that increases precision of TOBEC measurements. This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.

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“…We released bats back in their roost box after all data were collected. Body condition was calculated as mass divided by forearm length [28, 29]. We use forearm length as our measured indicator of size as this is the most commonly collected measure of bats.…”

Section: Methodsmentioning

confidence: 99%

Common Noctule Bats Are Sexually Dimorphic in Migratory Behaviour and Body Size but Not Wing Shape

et al. 2016

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Within the large order of bats, sexual size dimorphism measured by forearm length and body mass is often female-biased. Several studies have explained this through the effects on load carrying during pregnancy, intrasexual competition, as well as the fecundity and thermoregulation advantages of increased female body size. We hypothesized that wing shape should differ along with size and be under variable selection pressure in a species where there are large differences in flight behaviour. We tested whether load carrying, sex differential migration, or reproductive advantages of large females affect size and wing shape dimorphism in the common noctule (Nyctalus noctula), in which females are typically larger than males and only females migrate long distances each year. We tested for univariate and multivariate size and shape dimorphism using data sets derived from wing photos and biometric data collected during pre-migratory spring captures in Switzerland. Females had forearms that are on average 1% longer than males and are 1% heavier than males after emerging from hibernation, but we found no sex differences in other size, shape, or other functional characters in any wing parameters during this pre-migratory period. Female-biased size dimorphism without wing shape differences indicates that reproductive advantages of big mothers are most likely responsible for sexual dimorphism in this species, not load compensation or shape differences favouring aerodynamic efficiency during pregnancy or migration. Despite large behavioural and ecological sex differences, morphology associated with a specialized feeding niche may limit potential dimorphism in narrow-winged bats such as common noctules and the dramatic differences in migratory behaviour may then be accomplished through plasticity in wing kinematics.

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Evaluation of morphological indices and total body electrical conductivity to assess body composition in big brown bats

Cited by 29 publications

References 34 publications

Hibernation energetics of free-ranging little brown bats

Hibernation energetics of free-ranging little brown bats

Evaluation of Total Body Electrical Conductivity to Estimate Body Composition of a Small Mammal

Common Noctule Bats Are Sexually Dimorphic in Migratory Behaviour and Body Size but Not Wing Shape

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