Variation In Body Mass Research Articles

Seasonal Dynamics of Lipid Metabolism and Energy Storage in the Brazilian Free-Tailed Bat

As small, flying, mammalian endotherms, insectivorous bats are adapted to operate at high levels of energy expenditure. In response to seasonally variable challenges, we predicted that bats should balance energy budgets by flexibly adjusting aspects of their physiology or behavior in ways that elevate metabolic capacity. We examined variation in energy storage and pathways for oxidative metabolism in Brazilian free-tailed bats (Tadarida brasiliensis) related to estimated costs associated with reproduction and migration. We collected pectoral muscle and liver from female T. brasiliensis at six time points during the summer and fall and measured changes in the activity of four enzymes involved with lipid metabolism. Body mass varied substantially with life-cycle stage, suggesting that rapid accumulation and use of fat stores occurs in response to current and anticipated energy demands. Catabolic enzyme activity (carnitine palmitoyl transferase [CPT], 3-hydroxyacyl-CoA dehydrogenase [HOAD], and citrate synthase [CS]) in the muscle was increased during lactation compared with early pregnancy but exhibited no change before fall migration. While there was no temporal change in lipid biosynthetic capacity in the liver, fatty acid synthase activity was negatively correlated with body mass. Variation in body mass and enzyme activity in T. brasiliensis during the summer suggests that stored energy is mobilized and lipid oxidative capacity is increased during periods of increased demand and that lipid biosynthetic capacity is increased with depletion of fat stores. These results suggest that bats are able to flexibly adjust metabolic capacity based on energy requirement to maintain energy balance despite high levels of expenditure.

Muscle derangement and alteration of the nutritional machinery in NSCLC.

Weight loss and depletion of nutritional status are frequent presentation hallmarks in non-small cell lung cancer (NSCLC). Decline in muscle mass is a major component in weight loss and may have both a prognostic and predictive value for survival and treatment-related toxicities. Recent findings suggest that weight and skeletal muscle mass gain during treatment may represent surrogate markers for outcome in advanced NSCLC patients. Herein we present an in-depth view of the impact of nutritional status derangements on NSCLC patients' outcome, focusing on lean body mass variations during disease course. We explored the impact of malnutrition with a major attention on novel treatment options. We reviewed molecular, metabolic and immunological mechanisms underlying muscle-wasting condition, which may exhibit a meaningful targeting potential. Incorporating a specialized and accurate body composition assessment into a comprehensive, patient-centered and tailored intervention will facilitate the achievement of nutritional goals and optimal care for lung cancer patients.

Individual Spatial Consistency and Dietary Flexibility in the Migratory Behavior of Northern Gannets Wintering in the Northeast Atlantic

Migration is a fundamental behavioral process prevalent among a wide variety of animal taxa. As individuals are increasingly shown to present consistent responses to environmental cues for breeding or foraging, it may be expected that approaches to migration would present similar among-individual consistencies. Seabirds frequently show consistent individual differences in a range of traits related to foraging and space-use during both the breeding and non-breeding seasons, but the causes and consequences of this consistency are poorly understood. In this study, we combined analysis of geolocation and stable isotope data across multiple years to investigate individual variation in the non-breeding movements and diets of northern gannets Morus bassanus, and the consequences for changes in body condition. We found that individuals were highly repeatable in their non-breeding destination over consecutive years even though the population-level non-breeding distribution spanned >35° of latitude. Isotopic signatures were also strongly repeatable, with individuals assigned to one of two dietary clusters defined by their distinct trophic (δ15N) and spatial (δ13C) position. The only non-breeding destination in which the two dietary clusters co-occurred was off the coast of northwest Africa. The majority of individuals adopted a consistent foraging strategy, as they remained within the same dietary cluster across years, with little variation in body mass corrected for size among these consistent individuals. In contrast, the few individuals that switched clusters between years were in better condition relative to the rest of the population, suggesting there may be benefits to flexibility during the non-breeding period. Our results indicate that a consistent migratory strategy can be effective regardless of wintering region or diet, but that there may be benefits to those individuals able to display flexibility. This appears to be an important behavioral strategy that may enhance individual condition.

The role of autumnal swarming behaviour and ambient air temperature in the variation of body mass in temperate bat species

The role of autumnal swarming behaviour and ambient air temperature in the variation of body mass in temperate bat species

Intraspecific variation of Megalonychid sloths from Hispaniola and the taxonomic implications

ABSTRACT Megalonychid sloth fossils have been found on numerous islands across the Antilles, with most associated with the Greater Antilles. New specimens from the Dominican Republic permit exploration of intraspecific variation ranges the recognised taxa (Acratocnus, Parocnus, Megalocnus, Neocnus) of Hispaniola. Using length of upper limb bones as a proxy for body mass, sexual dimorphism and geographic variation were explored, along with additional assessments about changes to the known taxonomy resulting from intraspecific variations. Sexual dimorphism is considered to occur, at differing levels, for all Hispaniola sloths, supported by the presence of large and short morphs within individual localities. Geographically, Acratocnus exhibits differences between northern and southern paleo-island sites, suggesting the existence of two subspecies or an unrecognised new, northern paleo-island species. Megalocnus zile is considered a junior synonym of Parocnus serus, as it falls within morphological variation ranges for that taxon. Parocnus specimens from Parque Nacional del Este are ~15% smaller than all other sites, regardless of paleo-island association, and may represent a new species. Results for Neocnus demonstrate the necessity for a reassessment of the current taxonomy and recognised characters. Radiometric dates are needed for more localities in order to rule out patterns resulting from temporal variation.

Is Wobble Board Balance Performance Influenced by Sex and Anthropometric Characteristics?

It has been demonstrated that balance can be influenced by anthropometric characteristics and sex. However, controversial findings are reported, mainly due to the large variability in subjects tested and methodologies adopted. Therefore, new hi-tech approaches, able to limit this variability, are needed to accurately evaluate balance control. PURPOSE: To assess the influence of anthropometric characteristics and sex on computerized wobble board (WB) balance measures. METHODS: Forty-eight (women=24; men=24) young (age=24.0±3.0years) adults were selected to cover a wide range of anthropometrics (mass=64.6±11.5kg; height=167.3±8.5cm; body mass index [BMI]=23.0±3.2kg·m-2). Subjects performed three 30-second trials per limb on a WB equipped with a triaxial accelerometer. Time (s) spent on the platform keeping it flat at 0° was collected for subsequent analysis. Pearson’s correlation was used to evaluate the relationships between WB values and the anthropometrics (height, mass, BMI). ANOVA was used to examine WB performance differences between sex for dominant and non-dominant limbs (p<0.05). RESULTS: The measured anthropometrics did not significantly correlate with the WB performance. Although women (dominant limb=19.2±4.6s; non-dominant limb=19.8±4.9s) presented better balance than men (dominant limb=18.8±3.5s; non-dominant limb=19.1±4.1s), no significant sex differences were observed for both dominant (p=0.73) and non-dominant (p=0.60) limb. CONCLUSIONS: Interestingly, anthropometrics and sex did not affect the WB performance. Due to the close relationship previously reported between WB training and ankle muscles activity, it could be hypothesized that the WB performance is affected by their strength, stiffness or activity. WB improvements after training protocol using WB exercises, can be understood as consistent change in performance not affected by other source of variability such as variation in body mass. Therefore, trainable neuromuscular factors should be targeted during training protocols to gain postural control improvements, without controlling the anthropometrics, independently from the sex. From a clinical point of view, during preventive and rehabilitative programs a special attention should be given to the ankle muscles.

Validation of Body Condition Indicators for Monitoring Changes in Populations of Sika Deer (Cervus nippon) at a Landscape Scale

The estimated number of sika deer within the Tanzawa Mountains has decreased since the Kanagawa Prefecture sika deer management plan commenced. Meanwhile, unit-specific culling has resulted in various trends in deer density across small monitoring units. Deer abundance is usually surveyed within small monitoring units; therefore, the evaluation of deer abundance changes across the entire management area comprising individual units is difficult. We examined the relationship between deer body condition indicators and densities estimated at both individual unit and entire management scales in the Tanzawa Mountains during 2004–2015. Winter fawn body mass in the study area increased at least until 2011, irrespective of the increase/decrease in deer density in each unit. Observed variations in body mass were related to the estimated number of deer within the entire management area. Winter fawn hind foot length was not related to any density estimates. Inconsistencies between deer density changes in each unit and body mass might derive from the deer movement between units and mitigation of density-dependent food limitations caused by a reduction in the number of deer within the entire management area. We suggest that winter fawn body mass can provide additional evidence of deer abundance changes within management areas.

Seasonal variation in body mass, body composition and activity-induced energy expenditure: a long-term study.

Seasonal variation in body mass is a model for the study of body mass regulation. Here a long-term study is presented on body mass, body composition, and activity-induced energy expenditure in a subject with a large seasonal variation in body mass of about 3.0 kg. Body mass was assessed daily over >20 consecutive years. Daily assessment of activity-induced energy expenditure was performed over the last 10 years. Body composition was assessed monthly for 1 year in the middle and at the end of the observation interval. Additionally, data were compared with data on body composition, resting energy expenditure, and total daily energy expenditure of the same subject as a participant in published studies. Body mass showed a pronounced seasonal variation, associated with a synchronous variation in physical activity. Body mass peaked in the cold winter months when physical activity reached the lowest annual value and decreased to the lowest value in mid-summer when daily physical activity peaked. The seasonal variation in body mass consisted mainly of body fat. Longitudinally, over the past 8 years of the observation interval, average fat-free mass showed a decrease of 1.0 kg and fat mass increased 0.8 kg. In a subject with a pronounced seasonal variation in physical activity, activity-induced variation in energy requirement was covered by an annual variation in body mass, mainly as fat. Maintenance of activity-induced energy expenditure did not protect against loss of fat-free body mass with advancing age.

Morphological and Behavioral Correlates of Long-Term Bird Survival in Selectively Logged Forest

The response of biodiversity to land-use change has been a central focus in applied ecological research for close to half a century. However, despite a vast body of literature, our understanding of how species traits influence demographic vital rates in anthropogenically-modified habitats is remarkably scant. Such an understanding is crucial because vital rates determine population viability in modified habitats, and underlie emergent occupancy, abundance and community-level patterns. I use 5,298 captures of 3,310 individuals of 20 species across seven years to test how four traits—(a) inherent survival, (b) body size, (c) social behaviour, and (d) migratory strategy—influence annual survival in selectively logged versus intact forest in tropical montane eastern Himalayan birds. In general, variation in body mass and alternative behavioural strategies (e.g., mixed-species flocking versus solitary behaviour) were not associated with survival differences in intact forest. However, species with high inherent survival, year-round residents, and species that did not participate in mixed-species flocks had appreciably lower survival in logged forest compared with intact forest. Solitary foragers, for instance, faced a 30% decline in survival in logged forest compared with intact forest. Non-migratory habit and solitary foraging behaviour might make species vulnerable to extinction in logged forest through reduced survival, an especially important process in influencing population viability. Identifying how species’ traits modulate their response to land-use change by altering survival rates is crucial to predict species responses to forest modification, and to better plan and manage biodiversity-friendly forest use.

Body size mediates the relationship between spider (Arachnida: Araneae) assemblage composition and prey consumption rate: results of a mesocosm experiment in the Yukon, Canada.

Many ecological assemblages are undergoing rapid changes in composition and diversity, and changes at one trophic level can have direct and cascading effects on other trophic levels. Prey consumption typically increases with predator diversity due to niche complementarity and sampling effects. However, the effect of functional traits and interactions between predator species mean that the relationship is far from simple. In July 2016, we performed a series of experiments in the Yukon, Canada, to investigate the relationship between spider assemblage composition and prey consumption, with a focus on the wolf spider Pardosa lapponica (Thorell 1872). We carried out feeding trials, in which P. lapponica and other spider species were offered potential prey, as well as mesocosm experiments, in which we varied spider assemblage composition within small enclosures. We confirmed that P. lapponica is a generalist consumer, individual consumption rate increased with spider body size, and that intraguild predation is present. We found that prey consumption was greatest in the least diverse assemblage but consumption did increase with predator functional trait variation and biomass. The best model of prey consumption included predator assemblage composition, variation in body mass, biomass, and all interactions. The body size of a spider affects its trophic niche, energy requirements, and its interactions with other spiders. As a result, body size mediates the relationship between spider assemblage composition and prey consumption. A deeper understanding of the relationships between traits and functions will allow us to better predict the effect of species loss or gain on ecosystem functions.

Mass or pace? Seasonal energy management in wintering boreal passerines

Research on winter energy management in small vertebrates has focused on the regulation of body mass (BM) within a framework of starvation-predation trade-off. Winter-acclimatized birds exhibit a seasonal increase in both BM and basal metabolic rate (BMR), although the patterns of co-variation between the two traits remain unknown. We studied this co-variation in three different species of wild titmice, great, blue and willow tits, originating from two boreal regions at different latitudes. Seasonal change in BM and BMR was inter-dependent, particularly in the great tit; however, by contrast, no seasonal change was observed in the willow tit. BMR changed non-linearly in concert with BM with a peak in midwinter for both blue and great tits, whereas such non-linear pattern in willow tit was opposite and independent of BM. Surprisingly, BMR appears to be more sensitive to ambient temperatures than BM in all three species studied. Energy management is a multifaceted strategy that cannot be fully understood without considering reserve levels and energy expenditure simultaneously. Thus, our study indicates that the prevailing conceptual framework based on variation in BM alone is insufficient to understand seasonal energy management in small wintering passerines.

Estimating body mass of Florida white-tailed deer from standard age and morphometric measurements

Context Measuring a mammal’s body mass has importance in understanding nutritional condition, reproductive biology and ecology. It can be impractical for a researcher to measure the body mass when equipment needed to weigh individuals is inadequate or unavailable. Aims The purpose of this study was to develop a model to accurately estimate the body mass of hunter-harvested Florida white-tailed deer (Odocoileus virginianus osceola, Odocoileus virginianus seminolus) based on the relationship between scale mass, sex and standard age and morphometric measurement predictor variables easily obtainable in the field. Methods An information-theoretic approach was used to evaluate simple and multiple linear regression models with 67% of the data, and the best model in the set was validated using the remaining 33%. Key results Chest girth was the best single predictor of body mass. A global model including sex, age, age2 and body length variables was better supported than chest girth alone, and subspecies information did not contribute significantly to the body-mass–predictor-variable relationship. The best model explained 98.5% of the variation in body mass as follows: body mass (kg) = –18.41 + 6.53 × sex (0 = female, 1 = male) + 5.04 × age (year) – 0.49 × age2 (year2) + 4.76 × 10−3 × chest girth2 (cm2) + 0.12 × body length (cm). The 95% confidence interval on the bias of the estimated body mass of the best model was –0.50 to 0.59 kg. The difference between estimated and scale body mass was –0.04 kg ± 0.28 (s.e.). Conclusions Individuals maintained a similar proportion of body mass to predictor variables, and differences between the observed and estimated body mass of model applied to the validation dataset were not significant. Implications The validated body-mass-estimation model presented will enable accurate estimates of the body mass of white-tailed deer in cases where standard age and morphometric measurements are available, but the individuals were not weighed. These results provide a basis to formulate and parameterise body-mass-estimation models for other white-tailed deer subspecies and populations. Without the need for specialised equipment, the body-mass-estimation model can be used by personnel involved in white-tailed deer research, management and sport hunting to assess trends in individual and population health in support of this species’ conservation. Photograph by Carlton Ward Jr.

Energetics of migratory bats during stopover: a test of the torpor-assisted migration hypothesis.

The torpor-assisted migration hypothesis posits that migration is facilitated in bats by the use of torpor during stopover roosting periods, and predicts that at stopover, bats regulate time in torpor facultatively so that daily energy expenditure is independent of ambient roosting temperature. Energy savings can thus be directed to migratory movement. However, direct measurements of total roosting energy expenditure in relation to ambient and body temperature are lacking. We captured migratory silver-haired bats (Lasionycteris noctivagans; ∼11 g) at Long Point, ON, Canada, in spring and autumn 2016. We used quantitative magnetic resonance analysis to measure body composition change and energy expenditure over a 12h roosting period in a ventilated incubator at 10, 17 and 25°C. We assessed the effects of season, body mass, sex and age on energy expenditure. We found that daily energy expenditure was independent of roosting temperature, and that this was achieved by flexible use of torpor. Variation in body mass at capture was driven mainly by differences in fat, and the amount of body fat was negatively related to torpor use, particularly in spring. Season, sex and age also affected torpor use and energy expenditure, notably with pregnant females being generally fatter and using less torpor than males in spring. We estimate that stopover contributes only 15-20% to the total energy costs of migration in bats compared with 70% or more in typical birds. This study provides support for the torpor-assisted migration hypothesis, and furthers our understanding of the energy budgets of migratory bats.

Factors influencing hydration status during a National Collegiate Athletics Association division 1 soccer preseason

ObjectivesTo investigate the roles that training load and environmental conditions have on fluid balance during a collegiate men’s soccer preseason. DesignObservational study. MethodsTwenty-eight male collegiate soccer players (mean±SD; age, 20±1.7y; body mass (BM), 79.9±7.3kg; height, 180.9±6.8cm; body fat, 12.7±3.1%; VO2max, 50.7±4.3ml·kg−1·min−1) participated in this study. Prior to (PRE) and following (POST) each team session, BM, percent BM loss (%BML) and hydration status was measured. Participants donned a heart rate and GPS enabled monitor to measure training load. For all team activities, ambient temperature (TAMB) and relative humidity (RH) were obtained from the nearest local weather station. Participants consumed 500mL of water as part of the team-based hydration strategy before and after training session. Stepwise linear regression was used to identify the variables that predicted %BML. Significance was set a-priori p<0.05. ResultsTotal distance covered predicted %BML during all preseason activities (r2=0.253, p<0.001), with TAMB and RH further adding to the model (r2=0.302, p<0.001). %BML never exceeded 2% of BM during any one session and daily variation in BM was <1% from baseline measures. Urine specific gravity was greater than 1.020 on 12/15days and UCOL was above 4 on 13/15days, indicating a state of hypohydration. ConclusionsTotal distance covered was the best predictor for the extent of body water losses during a collegiate preseason. While the team-based hydration strategy during preseason was successful in minimizing fluid losses during activity, participants arrived hypohydrated 80% of the time, necessitating a greater focus on daily fluid needs.

Electrocardiograms of mice selectively bred for high levels of voluntary exercise: Effects of short-term exercise training and the mini-muscle phenotype

Changes in cardiac function that occur with exercise training have been studied in detail, but those accompanying evolved increases in the duration or intensity of physical activity are poorly understood. To address this gap, we studied electrocardiograms (ECGs) of mice from an artificial selection experiment in which four replicate lines are bred for high voluntary wheel running (HR) while four non-selected lines are maintained as controls (C). ECGs were recorded using an ECGenie (Mouse Specifics, Inc.) both before and after six days of wheel access (as used in the standard protocol to select breeders). We hypothesized that HR mice would show innate differences in ECG characteristics and that the response to training would be greater in HR mice relative to C mice because the former run more. After wheel access, in statistical analyses controlling for variation in body mass, all mice had lower heart rates, and mice from HR lines had longer PR intervals than C lines. Also after wheel access, male mice had increased heart rate variability, whereas females had decreased heart rate variability. With body mass as a covariate, six days of wheel access significantly increased ventricle mass in both HR and C males. Within the HR lines, a subset of mice known as mini-muscle individuals have a 50% reduction in hindlimb muscle mass and generally larger internal organs, including the heart ventricles. As compared with normal-muscled individuals, mini-muscle individuals had a longer QRS complex, both before and after wheel access. Some studies in other species of mammals have shown correlations between athletic performance and QRS duration. Correlations between wheel running and either heart rate or QRS duration (before wheel running) among the eight individual lines of the HR selection experiment or among 17 inbred mouse strains taken from the literature were not statistically significant. However, total revolutions and average speed were negatively correlated with PR duration among lines of the HR selection experiment for males, and duration of running was negatively correlated with PR duration among 17 inbred strains for females. We conclude that HR mice have enhanced trainability of cardiac function as compared with C mice (as indicated by their longer PR duration after wheel access), and that the mini-muscle phenotype causes cardiac changes that have been associated with increased athletic performance in previous studies of mammals.

Reconstructing body mass of the Australian dingo (Canis dingo) from two simple measurements of the hard palate

The ability to determine body mass from skulls is valuable for understanding various ecological, physiological, and evolutionary factors. In the Canidae, numerous methods to reconstruct body mass from measurements of the skull have been proposed, however there is no one-size fits all approach that can be applied across all species and subspecies. Added to this, current methods of reconstructing body mass are often complex, and have relatively high error rates. We aimed to produce a multivariate regression equation to estimate body mass of the Australian dingo (Canis dingo) from simple measurements of the skull, whilst ensuring that it could also be used in studies of encephalisation. To do this, we focussed on palate length (PL), palate width (PW) and the length of the first upper molar (M1). A total of 128 adult dingo (64 male; 64 female) crania from one region of Australia with known body mass were measured. Overall, the combination of PL and PW was the best predictor of body mass, with M1 having poor predictability. The model, mass (kg) = 0.246 ∗ (PL) + 0.320 ∗ (PW) − 24.757 produced a prediction error of 8.05%. Thus, these two measures of the palate provide simple and accurate predictors of body mass for the dingo. This will be useful for modern dingo specimens, as well as those found at archaeological sites and in museum collections that often consist of incomplete cranial material. The reconstruction of dingo body size is useful for evaluating variation in body mass through time, and across the Australian continent, particularly in the context of human activity.

The Influence of Psychological Stress, Depressive Symptoms, and Cortisol on Body Mass and Central Adiposity in 10- to-12-Year-Old Children

PurposeThe purpose of this study was to examine the influence of psychological stress and depressive symptoms on body mass and central adiposity in 10-to-12-year-old children and to determine the mediating role of cortisol in the relationships among psychological stress, depressive symptoms, body mass, or central adiposity. Design and MethodsThe convenience sample included 147 children (84 females; 63 males) who were recruited from one middle school and three elementary schools in a rural area of a southeastern state. Height, weight, waist circumference (WC), and salivary cortisol were measured. Children completed the Rating Scale for Pubertal Development for screening, Children's Depression Inventory, and the Feel Bad Scale. Bivariate correlation, multiple regression analyses, and univariate regression techniques were used in data analyses. ResultsA positive relationship between psychological stress and depressive symptoms (r = 0.559, p < .001) was found. Depressive symptoms explained a significant amount of the variance in body mass index (BMI) (β = 0.37, p ≤.001) and central adiposity (β = 0.40, p ≤ .001) when sex, race/ethnicity, puberty, and socioeconomic status were controlled. No statistically significant relationships were found between psychological stress and cortisol or between depressive symptoms and cortisol. ConclusionsDepressive symptoms were reported by normoweight, overweight, and obese children. Depressive symptoms accounted for variance in body mass and central adiposity.Practice ImplicationsIn addition to regular screening of BMI and WC, nurses and other health care professionals need to consider psychological factors that contribute to childhood obesity.

Individual study of anthropometric variation, energy and macronutrients intakes in Paralympic Track and Field athletes in different phases of the season

Abstract Aims: a) to measure individual variations in body mass (BM), sum of skinfolds (SSF) and energy intake of Paralympic track and field athletes b) to evaluate whether individual consumption of macronutrients meets recommended levels in three distinct periods of training. Methods: Ten Paralympic track and field athletes were evaluated during three periods: 1) end of season, 2) after vacation, and 3) preparation for the Paralympic Games London 2012. Food history and the 24-hour Dietary Recall methods provided information on daily food intake. To assess changes in body composition, we measured skinfolds and BM. Descriptive statistics were utilized to describe individual results. Results: BM varied among athletes and phases, but most (n=8) had higher SSF after vacation. Four athletes reported an increase in energy intake of more than 500 kcal during their vacation period, while eight athletes reported maintaining their intake in the preparatory phase for the competition. Carbohydrate intake was adequate for most athletes in the end of season period and in the preparatory phase for competition, and most athletes had reduced lipid intake after vacation and in the preparatory phase. Conclusion: We observed important variations in BM and SSF, in food intake and macronutrients between the three evaluated periods. The nutritional status of the athletes suggests that inadequacies that might affect the performance of sprinters and middle-distance runners are more likely to occur during the preparatory period before competitions.

Variability of Body Mass and Urine Specific Gravity in Elite Male Field Hockey Players During a Pre-Olympic Training Camp.

This field-based observational study was designed to examine the intraindividual variation of first morning body mass and urine specific gravity (Usg) in male hockey players (n = 22) during a 10-day training camp. It was also designed to evaluate the prevalence and interrelationship of morning hypohydration and postmatch dehydration using Usg and changes in body mass, respectively. Body mass and Usg were measured upon waking; body mass was also measured before and after matches. Individual means, SD, and coefficient of variation (CV) were calculated for morning body mass and Usg using 3, 6, and 8 days. Daily prevalence for euhydration and postmatch dehydration using morning Usg (<1.020) and changes in body mass (>-2%), respectively, were determined. Measurement of morning body mass and Usg for 3 days had low variability (CV < 1%) with no improvement at 6 or 8 days. Between 36% and 73% of players were considered euhydrated based on morning Usg. Postmatch body mass was reduced >1% in 50-85% of players, with up to 40% experiencing changes >-2%. Postmatch changes in body mass were unrelated to Usg the subsequent morning. These outcomes can be helpful in establishing criteria for detecting meaningful changes in morning body mass and Usg in similar settings, helping to monitor hydration status in elite male athletes. Despite ample fluid availability and consumption, many players experienced hypohydration and dehydration during the camp, indicating that careful monitoring and an individual fluid replacement approach are warranted in these environments.

Comparative functional responses of introduced and native ladybird beetles track ecological impact through predation and competition

Recent advances in invasion research has highlighted that differences in the feeding ecology of native and non-native species manifest through differences in their functional responses (FRs) and that FRs track ecological impact. Further, as with plant competition studies, differential resource use patterns may illuminate competition mechanisms among animal taxa. Ladybirds are a diverse family of beetles that possess substantial variation in body mass across taxa. Further, some ladybird species have been widely introduced into novel habitats, where they may pose significant risks of ecological and economic harm. By controlling for allometric scaling, we tested the hypothesis that introduced Asian multicoloured ladybirds (Harmonia axyridis) are more efficient predators on aphids than trophically-analogous, native convergent ladybirds (Hippodamia convergens). We utilized a prey-replacement FR design, and assessed rates of pea aphid consumption as a function of initial prey density. H. axyridis possessed significantly higher absolute and mass-adjusted FRs (Type II) than the native species, consistent with expectations. The higher FR was mediated by reduced handling time, suggesting that the ability of H. axyridis to manipulate and digest prey exceeds that of H. convergens. Our feeding results may explain, in part, the increasing occurrence and abundance of the introduced species, and documented declines of native species of prey and competitor in invaded habitats.