High-energy Foods Research Articles

Spatial patterns of child growth in Papua New Guinea and their relation to environment, diet, socio-economic status and subsistence activities

Anthropometric data from the 1982/83 Papua New Guinea (PNG) National Nutrition Survey were analysed to identify geographical patterns of child growth and investigate their relation to a wide range of environmental, dietary and socio-economic variables. Standardized growth scores for length-for-age (LAZ), weight-for-age (WAZ) and weight-for-length (WLZ) were calculated based on an internal PNG growth reference. Hierarchical Bayesian spatial models based on conditional autoregressive (CAR) priors were subsequently used to model spatial patterns in scores and their relation to different sets of covariates. The geographical differences were bigger for linear growth than for increases in weight. Growth was most reduced in parts of Milne Bay Province, Madang Province, the Torricelli/Prinz Alexander Ranges, and in the area occupied by Angan people. Socio-economic status was the most important factor determining variation in growth within populations. Differences in diet and, to a lesser extent, the physical environment were the main determining factor of differences among populations. Covariate adjustment accounted for more spatially structured variation in LAZ and WAZ than in WLZ. All variables indicating higher socio-economic status were correlated with better growth, as was a high consumption of imported and local high quality foods such as cereals, legumes, tinned fish/meat or fresh fish. This indicates that nutritional interventions in PNG should aim at promoting the consumption of such high energy and high protein foods as well as strengthening the general economic base of rural populations.Es wurden anthropometrische Daten von der Nationalen Ernährungsstudie in Papua Neu Guinea (PNG) aus den Jahren 1982/83 analysiert, um geographische Muster des kindlichen Wachstums und deren Beziehungen zu einer großen Anzahl von Variablen der Umwelt, der Ernährung und des sozio-ökonomischen Umfeldes zu untersuchen. Auf der Basis von internen PNG Wachstumsreferenzwerten wurden standardisierte Wachstums-Scores für length-for-age (LAZ), weight-for-age (WAZ) und weight-for-length (WLZ) berechnet. Anschließend wurden hierarchische Bayessche räumliche Modelle basierend auf konditionalen autoregressiven (CAR) Priors benutzt, um räumliche Scores-Muster und deren Beziehung zu verschiedenen Sätzen von Covariaten zu modellieren. Beim linearen Wachstum waren die geographischen Differenzen größer als bei den Zunahmen des Körpergewichts. Die stärkste Verringerung des Wachstums fand sich in Teilen der Provinz Milne Bay, in der Provinz Madang, in den Torricelli/Prinz Alexander Ranges und in dem von den Angan People bewohnten Gebiet. Der sozio-ökonomische Status war der wichtigste Einflussfaktor hinsichtlich der Variabilität des Wachstums innerhalb von Populationen. Die Unterschiede zwischen Populationen wurden am stärksten durch Unterschiede in der Ernährung und in geringerem Ausmaß durch die physische Umwelt determiniert. Die Covariaten-Adjustierung erklärte die mehr räumlich strukturierte Variabilität von LAZ und WAZ gegenüber WLZ. Alle Variablen, die einen höheren sozio-ökonomischen Status anzeigten (wie z. B. ein hoher Verbrauch von importierten und von heimischen qualitativ hochwertigen Nahrungsmitteln wie Getreide, Hülsenfrüchten, Fisch-/Fleischkonserven oder frischem Fisch), waren mit einem besseren Wachstum korreliert. Dies weist darauf hin, dass Ernährungsinterventionen in PNG darauf abzielen sollten, den Verbrauch von solchen energie- und proteinreichen Nahrungsmitteln zu fördern sowie die allgemeine ökonomische Basis der Landbevölkerung zu stärken.Des données anthropométriques de l'Enquête Nationale de Nutrition de Papouasie-Nelle Guinée (PNG) de 1982/83 sont analysées afin d'identifier les modalités géographiques de la croissance ainsi que pour étudier leurs relations avec une très large gamme de variables environnementales, socio-économiques et alimentaires. On a calculédes scores standardisés de la croissance: longueur-pour-l'âge (LAZ), poids-pour-l'âge (PAZ) et poids-pour-longueur (PLZ) sur la base de références de croissance internes àla PNG. Des modèles bayésiens spatiaux et hiérarchiques établis sur des antécédents autorégressifs conditionnels, sont ensuite utilisés afin de modéliser les répartitions spatiales des scores et leurs relations avec différentes séries de covariants. Les différences géographiques de la croissance sont plus marquées pour la croissance linéaire que pour les accroissements en poids. La croissance est la plus faible dans des fractions des provinces de Milne Bay et de Madang, dans les chaînes de Torricelli/Prinz Alexander et dans la zone de peuplement Angan. Le statut socio-économique est le facteur le plus important qui détermine la variation en croissance au sein des populations. Les différences de diète et dans une moindre mesure l'environnement physique sont les facteurs déterminant les différences entre les populations. L'ajustement des covariants indique une variation plus structurée des LAZ et PAZ en fonction de l'espace que des PLZ. Toutes les variables qui indiquent un meilleur statut socio-économique ainsi qu'une consommation élevée en nourriture, importée ou locale de haute qualité: céréales, légumes, poisson en boîte ou poisson frais, sont corrélées avec une croissance plus forte. Ceci indique que les interventions nutritionnelles en PNG devraient viser àpromouvoir la consommation de ces aliments riches en énergie et en protéines, aussi bien qu'à renforcer l'assiette économique générale des populations rurales.

Food selection by the white-footed mouse (Peromyscus leucopus) on the basis of energy and protein contents

We studied the combined effects of energy and protein contents on food selection by the white-footed mouse, Peromyscus leucopus. Our objective was to determine how variation in levels of a food component affected the overall attractiveness of a food to the mice and whether trade-offs are made in selecting dietary protein compared with energy. We conducted food-selection tests in the laboratory and field using foods containing different combinations of energy and protein levels. In the laboratory, P. leucopus were offered a choice between a high-energy and a low-energy food with the protein level held constant and between a high-protein and a low-protein food with the energy level held constant. The field study was set up to offer an encounter with all four combinations of energy and protein simultaneously. We also tested for preferred levels of protein using pairwise food-selection tests in the laboratory. In the laboratory and field tests, P. leucopus selected high-energy foods that were low in protein, but avoided all foods with a high protein content. When given pairwise choices among foods containing 5, 15, 25, or 35% protein, P. leucopus consistently preferred the food with 15% protein. Peromyscus leucopus quickly detected differences in protein and energy levels in foods, selecting specific foods according to metabolic profitability and nutrient needs.

L'alimentation préhistorique : alimentation de demain ?

During evolution, food availability widely contributed to natural selection. In primates and in human beeings, the need for high-energy food influenced the alimentary behavior and social activity. Natural selection favored the species with optimal cerebral capacities for surviving according to the environmental conditions. Human feeding has widely varied during the last millenniums, namely after the development of agiculture 8000 years ago and the recent industrial revolution. During evolution, food availability strongly influenced genotype and phenotype. The human genetic endowment has changed relatively slightly since the appearance of modern human being during the late paleolithic. The inadequation between the nutrition of the modern human beeing and his physiological capacities could explain a number of metabolic and gastrointestinal diseases. These data suggest that diets more conform to our capacities or to individual and genetic variations should be proposed.

Secretory, Endocrine and Autocrine/Paracrine Function of the Adipocyte

Obesity is a major public health problem in Western countries, and >55% of adult Americans are overweight or obese. A major contributor to the epidemic of obesity is the current environment, which is characterized by increased availability of high energy foods and decreased physical activity. Several studies also demonstrated that genetic susceptibility contributes to obesity in some populations. Obesity research has focused primarily on the role of the hypothalamus in neuroendocrine regulation of food intake. However, a growing number of studies support a potential contribution of adipose tissue, via its newly discovered secretory function, to the pathogenesis of obesity and co-morbid conditions including cardiovascular disease, diabetes and hypertension. This paper will review the role of four factors secreted by adipose tissue (leptin, agouti, angiotensin II and prostaglandins) and their functions in the regulation of energy balance and whole-body homeostasis. Several other peptide and nonpeptide substances are secreted from adipose tissue; their function and regulation have been documented extensively.

Äldre och Nutrition

Adequate nutrition is crucial for frail and ill elderly. In Sweden, poor nutritional status among elderly in hospitals and in community care has been reported in mass media and study reports. A retrospective study of hospital records and community acts is here presented. Notes on nutrition of 94 patients (80 years>) during their last stay in acute somatic medical care were analysed. Also, community acts for those who had received home-care after discharge. Prospectively in addition, focusing the need for nutrition, one elderly person was observed and interviewed after discharge from hospital to community care in own home as a case study. Three questions were asked: 1) What was documented on nutritional needs during the acute medical care episode? 2) In case of home-care after discharge, what was documented on nutritional needs in community acts? 3) What actions for meeting demands for adequate nutrition is planned by community home-care services for an elderly client discharged from hospital to own home? In this sample notes on nutrition were made in 87 percent of the acute medical care patient records. In the community services acts, notes on nutrition were rare. In the case study, needs of high-energy food intake and psychological support during meals were not adequately planned for and met in home care. The conclusion is, that in order to undertake caring responsibilities for elderly, knowledge of nutritional needs, psychological and social support as well as documentation skills is necessary within all levels of care and important indicators of quality of care. At the community level, in plans for home care and in individual care of elderly clients, explicit and planned assessment must be made for nutritional needs and meal situation. Also, for the continuity of care between hospital and community care and evaluation.

The Epidemic of Severe Obesity: The Value of Surgical Treatment

The Epidemic of Severe Obesity: The Value of Surgical Treatment

Lambs fed protein or energy imbalanced diets forage in locations and on foods that rectify imbalances

Ruminants eat a variety of foods from different locations in the environment. While water, cover, social interactions, and predators are all likely to influence choice of foraging location, differences in macronutrient content among forages may also cause ruminants to forage in different locations even during a meal. We hypothesized that lambs forage at locations containing foods that complement their basal diet and meet their nutritional needs. Based on this hypothesis, we predicted that lambs ( n=12) fed a basal diet low in protein and high in energy would forage where a high-protein food (Food P) was located, and that lambs ( n=12) fed a basal diet low in energy and high in protein would forage where a high-energy food (Food E) was located. Food P was a ground mixture of blood meal (50%), grape pomace (30%), and alfalfa (20%) that contained 47% crude protein (CP) and 2.211 Mcal/kg digestible energy (DE). Food E was a ground mixture of cornstarch (50%), grape pomace (30%), and rolled barley (20%) that contained 6% CP and 3.07 Mcal/kg DE. Food P provided 212 g CP/Mcal DE, whereas Food E provided 20 g CP/Mcal DE. Lambs growing at a moderate rate require 179 g CP and 3.95 Mcal DE. During Trial 1, we determined if lambs foraged to correct a nutrient imbalance, and if they preferred a variety of foods (Foods P and E) to only one food at a location (Food P or E). During Trial 2, we determined if nutrient-imbalanced lambs foraged in the location with the food that corrected the imbalance when the location of the foods changed daily. During Trial 3, lambs were offered familiar foods (Foods P and E) at the location furthest — and novel foods (wheat and soybean meal) at the location nearest — the shelter of their pen. During all three trials, lambs foraged most at the location with the food that contained the highest concentration of the macronutrient lacking in their basal diet, but they always ate some of both foods. Lambs did not feed exclusively at the location with a variety of foods (P and E). Rather, they fed at the location nearest the shelter that contained the macronutrient lacking in their diet. As availability of the food with the needed macronutrient declined in one location, lambs moved to the nearest location that had food with the needed macronutrient. When food that complemented their basal diet was moved to a different location, lambs foraged in the new location. Collectively, these results show that lambs challenged by imbalances in energy or protein selected foods and foraging locations that complemented the nutrient content of their macronutrient imbalanced basal diets.

Obesity as a medical problem.

Obesity is now so common within the world's population that it is beginning to replace undernutrition and infectious diseases as the most significant contributor to ill health. In particular, obesity is associated with diabetes mellitus, coronary heart disease, certain forms of cancer, and sleep-breathing disorders. Obesity is defined by a body-mass index (weight divided by square of the height) of 30 kg m(-2) or greater, but this does not take into account the morbidity and mortality associated with more modest degrees of overweight, nor the detrimental effect of intra-abdominal fat. The global epidemic of obesity results from a combination of genetic susceptibility, increased availability of high-energy foods and decreased requirement for physical activity in modern society. Obesity should no longer be regarded simply as a cosmetic problem affecting certain individuals, but an epidemic that threatens global well being.

Antipredator vigilance of juvenile and adult thirteen-lined ground squirrels and the role of nutritional need

Juvenile thirteen-lined ground squirrels, Spermophilus tridecemlineatus, are less vigilant (i.e. they spend less time visually scanning the environment) than adults. To determine whether nutritional need was a potential cause of this difference, we supplemented two groups of free-ranging juveniles during the predispersal stage, while juveniles were still near and around the natal burrows. The high-energy food group (HEF: 11 squirrels) received peanut butter and oats while the low-energy food group (LEF: seven squirrels) received lettuce. Adults (14 squirrels) were also supplemented, but due to their greater home range sizes, it was not feasible to classify them as either HEF or LEF. To evaluate the effect of supplementation on antipredator vigilance, the behavioural act of visually scanning for predators, we videotaped individuals while they were foraging above ground during 5-min observation periods. Each squirrel was observed and weighed during three time periods over 23 days. From the videotape, we extracted measures of time spent vigilant, locomoting and foraging. All three categories of squirrels gained mass over the study period, but the HEF juveniles rapidly exceeded that of the LEF juveniles. Early in the study, LEF and HEF juveniles did not significantly differ in either body mass or time budgets, and, initially, both juvenile groups were similar to adults in the amount of time devoted to vigilance. Later in the study, the behaviour of HEF juveniles closely resembled that of adults (increased time devoted to vigilance and decreased time devoted to foraging), while LEF juveniles decreased vigilance and increased their foraging time. This study indicates that for thirteen-lined ground squirrels the lower vigilance of juveniles is due, at least in part, to the greater nutritional needs of young animals with consequent increases in foraging, which is largely incompatible with vigilance.

Paleolithic nutrition: a model for the future?

During evolution, food availability widely contributed to natural selection. In primates and in humans, the need for high-energy food influenced alimentary behaviour and social activity. Natural selection favoured the species with optimal cerebral capacities for surviving according to the environmental conditions. Human feeding varied widely during past millenniums, namely after the development of agriculture 8000 years ago and the recent industrial revolution. During evolution, food availability strongly influenced genotype and phenotype. The human genetic endowment has changed relatively little since the appearance of modern human beings during the late paleolithic age. The imbalance between nutrition of the modern human and his physiological capacities could explain a number of metabolic and gastrointestinal diseases. These data suggest that diets that conform more to our capacities or to individual and genetic variations should be proposed.

Dietary Determinants of Energy Intake and Weight Regulation in Healthy Adults

Until recently, the percentage of energy from dietary fat has been considered a primary determinant of body fatness. This review covers recent studies from our laboratory that challenge this notion. High and low fat diets matched for energy density, palatability and fiber resulted in similar mean voluntary energy intakes over 9 d; analysis of the individual foods in these diets showed that energy density and palatability were significant determinants of energy intake, independent of fat content. Path analysis further revealed that the influence of energy density on energy intake was in part direct, and in part indirect and mediated by palatability. In another study, dietary variety within food groups was shown to be an important predictor of body fatness, and the direction of the association depended on which food groups provided the variety, i.e., the variety of sweets, snacks, condiments, entrees and carbohydrates consumed was positively associated with body fatness, whereas the variety of vegetables was negatively associated. Last, a study of restaurant food and body fatness showed that the frequency of consumption of restaurant food was positively associated with body fatness, independent of education level, smoking status, alcohol intake and physical activity. Restaurant meals tend to be high in fat and low in fiber, and thus energy dense. Restaurants also typically serve a variety of palatable foods in large portions. The increasing variety of high energy foods available and the increasing proportion of household income spent on foods consumed away from home may help explain the U.S. national rising prevalence of obesity.

Hypertrehalosaemic peptides in the honeybee ( Apis mellifera): purification, identification and function

The corpora cardiaca (CC) of the Italian race (including also the africanised variety) of the honeybee ( Apis mellifera ligustica) contain approximately 3 pmol of a hypertrehalosaemic peptide. This peptide is identical in structure to the adipokinetic hormone (AKH) found in Manduca sexta, Mas-AKH. The CC of the dark European race of the honeybee ( Apis mellifera carnica) contain no detectable Mas-AKH or any other adipokinetic/hypertrehalosaemic peptide. This is the first report of the occurrence of this peptide in a non-lepidopteran insect and of an intraspecific variation with regards to the presence or absence of a hypertrehalosaemic peptide in the CC of an insect. Extracts of A. m. ligustica CC elicit a strong adipokinetic/hypertrehalosaemic response when injected into crickets and cockroaches but extracts of A. m. carnica CC elicit no such responses when injected into crickets, cockroaches and butterflies. A weak hypertrehalosaemic response to injected Mas-AKH was observed in winter bees of both races, but there was no response in spring/summer bees. However, if a seasonal difference exists, it is at best minimal. Honeybees always have access to a more than adequate supply of high energy food in the form of nectar or honey stored in the hive. Thus, though A. m. ligustica CC contain a hypertrehalosaemic peptide, there is neither a glycogen-mobilising function of this hormone nor an adequate glycogen store in their fat body for its effective utilisation.

Restructuring of Lepidoptera communities by introduced Vespula wasps in a New Zealand beech forest.

Introduced social wasps (Vespula vulgaris) reach high densities in some New Zealand beech forests, because honeydew provides an abundant high-energy food source. We manipulated wasp density to estimate an "ecological damage threshold" for large, free-living Lepidoptera larvae. There will be a continuum of ecological damage thresholds for wasp density depending on the prey species or habitat. Experimentally placed small caterpillars had a significantly higher survival rate than large caterpillars, and the survival rate of both groups decreased with increasing wasp density. Spring-occurring caterpillars have a probability of surviving of 0.90-0.95, assuming wasps are the only source of mortality. However, at the peak of the wasp season we predict caterpillars would have virtually no chance (probability of 10-78 to 10-40) of surviving to adults. Wasp abundance must be reduced by at least 88% to conserve the more vulnerable species of free-living caterpillars at wasp densities similar to those observed in our study sites. This equates to a damage threshold of 2.7 wasps per Malaise trap per day. It was exceeded for about 5 months of the year in non-poisoned sites. There are currently no biological or chemical control techniques available in New Zealand that will reduce wasp abundance below this damage threshold throughout the year. Our models show that most Lepidoptera with spring caterpillars will be able to persist, but species with caterpillars occurring in the peak wasp season will be eliminated.

Dietary Considerations in HIV and AIDS

Abstract Nutritional evaluation and counseling are important aspects of the overall care of patients with HIV and AIDS. While certain groups of patients, such as those with opportunistic infection and significant weight loss, malabsorption, or any medical condition affecting dietary intake or metabolism, should be referred to a physician nutrition specialist or registered dietician for evaluation and treatment, general nutritional care of other patients may be effectively accomplished in the setting of the primary care or infectious disease clinic. This article presents evidence from observational trials concerning the energy and protein needs of patients with HIV and AIDS, outlines the roles of various micronutrients in immune functioning, and summarizes data from observational studies concerning relationships between HIV infection and micronutrient status. The possible role of dietary and supplemental omega three fatty acids in AIDS is discussed as well. Provisional recommendations for levels of energy, protein, and micronutrient intakes based on epidemiological data and risk of toxicity are given, and tables of high energy and protein snacks and foods high in various micronutrients are supplied to assist clinical implementation of these recommendations.

Nutritional factors in the aetiology of multiple sclerosis: a case-control study in Montreal, Canada.

It has been suggested that nutrition and food patterns, particularly high consumption of animal fat and low intake of fish products, may play a role in the aetiology of multiple sclerosis (MS). The relation between nutritional factors and MS was studied among 197 incident cases and 202 frequency matched controls in metropolitan Montreal during 1992-1995. Dietary information was collected by employing a 164-item food frequency questionnaire in a face-to-face interview. An inverse association was observed between high body mass index (BMI) and the risk of MS, with an odds ratio (OR) of 0.76 (95% confidence interval [CI]: 0.61-0.95), per 5-unit increase in BMI, both sexes combined. In addition, taller women showed a greater risk for MS; the OR per 10 cm increase in height was 1.58 (95% CI: 1.06-2.35). In continuous variable analyses, using the difference between the lowest and highest quartile of intake as a unit, a positive association was observed with energy and animal fat intake. The OR per 897 kcal increase was 2.03 (95% CI: 1.13-3.67) and 1.99 (95% CI: 1.12-3.54) per 33 g of animal fat intake above the baseline. A significant protective effect was observed with other nutrients, including vegetable protein, dietary fibre, cereal fibre, vitamin C, thiamin, riboflavin, calcium, and potassium. Similar trends were seen for males and females when analysed separately. With respect to specific foods (as opposed to nutrients), a higher intake of fruit juices was inversely associated with risk (OR = 0.82; 95% CI: 0.74-0.92). A protective effect was also observed with cereal/breads intake for all cases combined (OR = 0.62; 95% CI: 0.40-0.97) and for fish among women only; pork/hot dogs (OR = 1.24; 95% CI: 1.02-1.51) and sweets/candy (OR = 1.29; 95% CI: 1.07-1.55) were positively associated with risk. The study generally supports a protective role for components commonly found in plants (fruit/vegetables and grains) and an increased risk with high energy and animal food intake.

The role of introduced predators and competitors in the decline of Kaka ( Nestor meridionalis) populations in New Zealand

We investigated the role of introduced predators and competitors in the population decline of kaka, Nestor meridionalis, a previously abundant forest parrot endemic to New Zealand. We provided supplementary food to test if a shortage of high energy food was limiting breeding in kaka. However, because most nesting attempts suffered from predation and we could not establish a non-treatment area, the role of competitors is still unclear. Kaka only bred in years when beech ( Nothofagus) seeded. Over 11 years and 20 breeding attempts we recorded only four fledglings surviving to independence. Nine young kaka and four adult females were killed on the nest. We suggest that stoats were predominantly responsible for this predation. Kaka are relatively common on offshore islands without stoats, even in the presence of other predators and competitors, but are scarce on all islands containing stoats. We predict that stoat predation will cause kaka to become extinct on mainland New Zealand unless stoats and/or kaka are managed.

The interaction of diet and stress in rats: high-energy food and sucrose treatment.

Exposure to inescapable shock typically reduces eating and body weight in rats. The present study examined the modulation of stress effects by prestress diet and poststress sugar availability. Maintenance on a high-fat, high-energy food attenuated stress-induced weight loss and anorexia and increased high-energy food selection when a low-energy wet mash was the only alternative. Access to sugar after stress also reduced short-term weight loss; among rats maintained on high-energy food, body weight was spared absolutely. The dependence of stress effects on pre- and poststress diet alternatives may speak to individual differences in the stress-eating relationship in humans. More generally, these results support a conceptualization of stress in terms of metabolic challenge and the integrated reorganization of energy regulatory processes.

The interaction of diet and stress in rats: High-energy food and sucrose treatment.

The interaction of diet and stress in rats: High-energy food and sucrose treatment.

The Grizzly Bears of Yellowstone: their ecology in the Yellowstone Ecosystem, 1959-1992

Review: The Grizzly Bears of Yellowstone: their ecology in the Yellowstone ecosystem, 1959-1992. By John J. Craighead, Jay S. Sumner, and John A. Mitchell Reviewed by Tom John Idaho Division of Environmental Quality Craighead, John J., Jay S. Sumner, and John A. Mitchell. The Grizzly Bears of Yellowstone: their ecology in the Yellowstone ecosystem, 1959- 1992. Washington, D.C.: Island Press, 1995. 535 pp. US $100 cloth ISBN: 1-55963-456-1. John Craighead and his colleagues report on grizzly research conducted over a third of a century. This big volume is organized in two parts. The first part deals with the pioneering study initiated in 1959 by John and his brother, Frank C. Craighead, Jr. The second part reports on bear research conducted in the Yellowstone ecosystem from 1974-1992. Concluding chapters assess the status of the grizzly in the early 1990's and provide the authors' critique of the federal plan for recovery of grizzly populations in the contiguous United States. The gap in this chronology represents a period between the forced termination of the Craighead study, due to conflicts with the National Park Service, and the initiation of work by the Interagency Grizzly Bear Management Team that was formed in response to widespread criticism of Park Service policies and management approaches. In a historical perspective, the authors document the slowly rising numbers of grizzlies in Yellowstone during the twentieth century in response to growing quantities of food in the form of garbage created by human visitors. Garbage dumps are characterized as ecocenters , defined as seasonal concentrations of high-energy food, which attract large numbers of bears. Aside from aesthetic considerations, the authors argue that the Yellowstone dumps were no different ecologically than concentrations of migrating salmon that attract bears in Alaska and elsewhere. The social hierarchy that formed annually during the early summer, allowing these powerful animals to co-exist in dense aggregations, is carefully described. Chapters on reproductive biology, rearing of offspring, population dynamics, food habits, and patterns of mortality, provide rich detail on the natural history of this species, much of it first

Effect of supplemental food on a cyclic Clethrionomys glareolus population at peak density

The impact of supplemental food on a cyclic bank vole Clethrionomys glareolus (Schreber, 1780) population was studied at peak density. We provided high energy food (sunflower seeds) to a 3.15 ha live-trapping grid and used a 5.06 ha unfed grid as a control. Density of adult females and immatures increased 3-fold in response to the extra food. In contrast, density of adult males did not change significantly. The rise in density of adult females, but not of adult males, altered the functional sex ratio. Loss rate of red adults remained the same as for controls, whereas immature loss rate was reduced by the extra food. Dispersal of immatures fom the control into the food supplemented grid was higher than the reverse. Growth and body mass of fed immatures were lower than controls. Reduced dispersal and increased immigration of immatures both contributed significantly to the overall rise in density when food was added.