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Results 251 - 300 of 915
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Xiang Zuo-Fu - - 2009
Data on mating and birth seasonality were recorded in wild black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Xiaochangdu in the Honglaxueshan National Nature Reserve, Tibet. This represents one of the harshest habitats utilized by any nonhuman primate. Variation in food availability, temperature, and photoperiod were examined to identify ecological influences on ...
Morrison Shawn F - - 2009
Food hoarding is a behavioral adaptation of some herbivores to manage food availability through time and space. In strongly seasonal environments, where summer growing seasons are short relative to winter, an earlier start to hoarding should increase the amount of vegetation stored for winter and improve subsequent survival. We examined ...
Vaughn Ashlee A - - 2008
Sperm competition occurs when 2 or more males copulate with a particular female during the same reproductive cycle, and their sperm compete to fertilize the female's available eggs. One strategy that male voles use to assess the risk and intensity of sperm competition involves responding to the presence of scent ...
De Avelar Daniel M - - 2008
In total, 1500 specimens (448 males and 1052 females) of the flea Ctenocephalides felis felis (Bouché (Siphonaptera: Pulicidae) were collected over a period of a year from 150 dogs captured by the Centro de Controle de Zoonoses de Belo Horizonte, Minas Gerais, Brazil. Microscopic examination of the dissected fleas revealed ...
Dahouda M - - 2008
1. An experiment was carried out with 120 helmeted guinea fowls during one year in Parakou (Benin). Feed intake, ingredient and chemical composition, along with the nutritional adequacy of scavenging diets were measured during the rainy season (November-February) and dry season (March-October) in order to propose supplementation strategies. Ingredients found ...
Groothuis Ton G G - - 2008
The increase or decrease in yolk androgens over the laying sequence of a clutch in birds may mitigate or enhance, respectively, the disadvantage of the last-hatched chicks, providing a potentially adaptive tool to adjust brood size to food conditions. This variation may involve a genetic component on which Darwinian selection ...
Kobayashi, Sharon R
Hawaiian tree snails of the subfamily Achatinellinae are unique to the Hawaiian Islands and highly endangered in the wild. Achatinellines are arboreal pulmonate gastropods characterized by slow growth and late age at first reproduction. Objectives of the laboratory studies described here were to add to the understanding of growth and ...
Nelson, Jessica Lynn
Riparian buffers composed of either native warm season or non-native cool season grasses are commonly planted alongside crop fields. Although their water quality function is well documented, few studies have examined grass buffers as habitat for arthropod communities. The aerial and epigeal arthropods were surveyed using pitfall traps and sticky ...
Baden Andrea L - - 2008
This study presents the first detailed morphometric measurements of wild caught black-and-white ruffed lemurs (Varecia variegata) from the eastern rainforests of Madagascar and aims to quantify the morphological variation present throughout their recognized range. One hundred and forty-four adult and juvenile individuals from 15 sites were sampled for 20 cranial, ...
Saito Atsuko - - 2008
Food transfer is considered to provide infants with additional nutrients during weaning, and in fact, its frequency peaks around this time. However, the mechanisms underlying such food transfer remain unclear. In this study, we investigated whether adult common marmosets (Callithrix jacchus) change their tolerance to offspring begging for food depending ...
Karlsson Bengt - - 2008
Butterflies have competing demands for flight ability depending on, for example, mating system, predation pressure, the localization of host plants and dispersal needs. The flight apparatus, however, is costly to manufacture and therefore trade-offs are expected since resources are limited and must be allocated between flight ability and other functions, ...
McNamara John M - - 2008
Tropical birds lay smaller clutches than birds breeding in temperate regions and care for their young for longer. We develop a model in which birds choose when and how often to breed and their clutch size, depending on their foraging ability and the food availability. The food supply is density ...
Duarte G - - 2008
The aim of this study was to determine whether the seasonal change in food availability provides a predictive cue that synchronizes the breeding season in goats adapted to the subtropical conditions of Northern Mexico. Groups of multiparous intact (n=7) and ovariectomized does bearing a subcutaneous implant constantly releasing estradiol-l7 beta ...
Tilly Jonathan L - - 2009
Whether or not oogenesis continues in the ovaries of mammalian females during postnatal life was heavily debated from the late 1800s through the mid-1900s. However, in 1951 Lord Solomon Zuckerman published what many consider to be a landmark paper summarizing his personal views of data existing at the time for ...
Reed T E - - 2008
Parasitism can be a major constraint on host condition and an important selective force. Theoretical and empirical evidence shows that maternal condition affects relative investment in sons and daughters; however, the effect of parasitism on sex ratio in vertebrates is seldom considered. We demonstrate experimentally that parasitism constrains the ability ...
Inness Claire L W - - 2008
While dietary restriction usually increases lifespan, an intermittent feeding regime, where periods of deprivation alternate with times when food is available, has been found to reduce lifespan in some studies but prolong it in others. We suggest that these disparities arise because in some situations lifespan is reduced by the ...
Vandegrift Kurt J - - 2009
1. Masting events in the autumn provide a carbohydrate-rich pulse of resources that can influence the dynamics of small mammals and their natural enemies. Similar patterns are observed with the periodical cicada emergence which provides a protein-rich pulse in the spring, but comparisons are confounded by timing and food type. ...
Visser Bertanne - - 2008
The ability of organisms to adapt to fluctuating food conditions is essential for their survival and reproduction. Accumulating energy reserves, such as lipids, in anticipation of harsh conditions, will reduce negative effects of a low food supply. For Hymenoptera and Diptera, several parasitoid species lack adult lipogenesis, and are unable ...
Tunnicliffe V - - 2008
The limpet Lepetodrilus fucensis McLean is very abundant at hydrothermal vents on the Juan de Fuca and Explorer Ridges in the northeast Pacific Ocean. This limpet is parasitized by an undescribed chitonophilid copepod throughout the limpet's range. The parasite copepodite enters the mantle cavity and attaches to the afferent branchial ...
Beehner Jacinta C - - 2008
Behavioral ecologists are increasingly adopting sophisticated non-invasive methods for measuring glucocorticoids from "excreta" because samples are easy to collect, animals are left undisturbed, and measures may be more reflective of external events than serum samples. Some of the most common predictors for hormone profiles in wild animals are seasonal changes ...
Vesakoski Outi - - 2008
Habitat choice of herbivores is expected to be a resolution of a trade-off between food and shelter. The resolution of this trade-off may, however, be dynamic within a species because distinct phenotypes may value these factors differently and the value may vary temporally. We studied this hypothesis in the marine ...
Rochester Johanna R - - 2008
In addition to well recognized effects on the zebra finch song system, we previously showed that post-hatch oral estrogen and xenoestrogen exposure disrupts reproduction by increasing eggshell breakage in females and decreasing fertility in males. Here we show that post-hatch exposure to estradiol benzoate (by oral gavage on days 5 ...
Schoech Stephan J - - 2008
Food supplementation experiments have provided considerable information about the importance of resource availability in timing reproduction. Supplemented birds usually advance breeding over non-supplemented controls. Initial observations suggested that degree of advancement in studies conducted at higher latitudes was less than in those at lower latitudes. We hypothesized that birds at ...
Anthony R E Sinclair - - 2008
An insular population of white-tailed deer Odocoileus virginianus introduced in 1896 to predator-free Anticosti Island, Quebec, has caused long-term changes in the plant community. Food quality declined as did body weight. Although different parameters of reproduction changed, overall reproductive rates remained similar, thus maintaining deer density and promoting further change ...
Rennie Michael D - - 2008
1. Differences in energy use between genders is a probable mechanism underlying sexual size dimorphism (SSD), but testing this hypothesis in the field has proven difficult. We evaluated this mechanism as an explanation for SSD in two North American percid species--walleye Sander vitreus and yellow perch Perca flavescens. 2. Data ...
Crawford, RJM; Marine and ...
Off South Africa, anchovy <i>Engraulis encrasicolus</i> and sardine <i>Sardinops sagax</i> are the main prey of African penguins <i>Spheniscus demersus</i>. The combined spawner biomass of these fish increased from less than one million t in 1996 to more than nine million t in 2001 and then decreased to four million t ...
Banks, Jonathan
We compared the behaviour, energy expenditure, and food intake of male and female South Island pied oystercatchers, Haematopus ostralegus finschi, breeding in pasture and crop paddocks in Canterbury. In this monogamous species, females spent more time inactive than males (P=0.03) and there was a trend for males to spend more ...
Fryer Geoffrey - - 2008
Jacob Christian Schäffer was the first to appreciate the morphological complexity of the microscopic crustacean Daphnia. His investigations, published in 1755, provide an excellent example of the difficulties facing those who, for the first time, attempted to elucidate the structure of extremely complicated animals of small size, of which there ...
Stickle William B - - 2008
The association of the scuticociliate Orchitophrya stellarum with 3 species of asteriid sea stars from the west coast of North America was studied by flushing the gonopore region with seawater and spawning the sea stars, along a latitudinal gradient of 2549 km between Pigeon Point, California, and Kodiak, Alaska. Asterias ...
Yamaguchi Sonoko - - 2008
To estimate the influence of water contamination by arsenic (As) on reproduction of crustaceans in Vietnam, we collected wild freshwater crab Somanniathelphusa pax from the Mekong Delta area in Vietnam, investigated gonadal development, and measured As concentration in hepatopancreas. In female crab, vitellogenesis was delayed in association with the increase ...
Palma P - - 2009
Endosulfan sulphate is the transformation product of endosulfan and it is the most frequent form of surface water contamination with endosulfan. The aim of this study was to evaluate the possible effects promoted by endosulfan sulphate in changes on the life cycle, embryo development and sex differentiation of Daphnia magna. ...
Byholm Patrik - - 2008
Food supplementation experiments have been widely used to get detailed insight into how food supply contributes to the reproductive performance of wild animals. Surprisingly, even though food seldom is distributed evenly in space, variation in local habitat quality has usually not been controlled for in food supplementation studies. With results ...
Jaeggi Adrian V - - 2008
Transfer of solid food from mothers or other adults to dependent offspring is commonly observed in various primate species and both nutritional and informational benefits have been proposed to explain the function of such food sharing. Predictions from these hypotheses are tested using observational data on wild orangutans (Pongo pygmaeus ...
Ezenwaji, H M; ;
The biology of the West African clariid, <i>Clarias macromystax</i>, was studied in Anambra river basin, Nigeria. The clariid occurred more abundantly and frequently in forest floodplain ponds than in other habitats, and was totally absent in the river systems. Length ranged from 9.7 to 30.2 cm TL and weight from ...
Bayol S A - - 2008
We have shown previously that a maternal junk food diet during pregnancy and lactation plays a role in predisposing offspring to obesity. Here we show that rat offspring born to mothers fed the same junk food diet rich in fat, sugar and salt develop exacerbated adiposity accompanied by raised circulating ...
Liker A - - 2008
1. Urbanized habitats differ from natural ones in several ecological features, including climate, food availability, strength of predation and competition. Although the effects of urbanization on avian community composition are well known, there is much less information about how individual birds are affected by these human-generated habitat differences. 2. In ...
Dinesh Diwakar S - - 2008
OBJECTIVE: To determine whether the use of long-lasting insecticidal nets (LLINS) at household level are effective in reducing the abundance of Phlebotomus argentipes, vector of anthroponotic visceral leishmaniasis in India, Nepal and Bangladesh. METHODS: The impact of two long-lasting nets (Olyset and PermaNet) on indoor sandfly abundance was evaluated in ...
Lee Ronald - - 2008
Why do humans survive so long past reproductive age, and why does juvenile mortality decline after birth, both contrary to the classic theory of aging? Previous work has shown formally that intergenerational transfers can explain both these patterns. Here, simulations confirm those results under weaker assumptions and explore how different ...
Doligez Blandine - - 2008
Experimental studies provide evidence that, in spatially and temporally heterogeneous environments, individuals track variation in breeding habitat quality to adjust breeding decisions to local conditions. However, most experiments consider environmental variation at one spatial scale only, while the ability to detect the influence of a factor depends on the scale ...
Robb Gillian N - - 2008
Supplementary food given to birds can have contemporary effects by reducing the risk of starvation, increasing survival and altering movements and reproductive performance. There is, however, a widely held perception that birds benefit from extra food over winter, but that it is better that they 'look after themselves' during breeding. ...
Pankevich Diana E - - 2008
OBJECTIVE: Stress increases the drive to consume calorically dense preferred foods suggesting an exogenous factor that may induce caloric overconsumption and weight gain. As females show heightened stress sensitivity and present with increased rates of obesity, we hypothesized that stress-induced increases in the motivation for preferred foods may be a ...
Bauchinger Ulf - - 2008
Long-distance migrants face the challenge of a short window for reproduction that requires optimal timing and full functional gonads. Male garden warblers (Sylvia borin) meet these demands by initiating testicular recrudescence during spring migration, enabling them to reproduce immediately after arrival at the breeding grounds. In a combined field and ...
Manjunatha B M - - 2009
The present study was carried out to examine the effect of season on in vivo oocyte recovery and embryo production in non-descriptive, Indian river buffaloes (Bubalus bubalis). Ovum pick up (OPU) was conducted twice a week for 8 weeks during peak (October-March) and low (April-September) breeding season in live buffaloes ...
Carey James R - - 2008
Although it is widely known that dietary restriction (DR) not only extends the longevity of a wide range of species but also reduces their reproductive output, the interrelationship of DR, longevity extension and reproduction is not well understood in any organism. Here we address the question: 'Under what nutritional conditions ...
Gil Diego - - 2008
Sibling competition has been shown to affect overall growth rates in birds. However, growth consists on the coordinated development of a multitude of structures, and there is ample scope for developmental plasticity and trade-offs among these structures. We would expect that the growth of structures that are used in sibling ...
Pfefferle Dana - - 2008
In a number of primate species, females utter loud and distinctive calls during mating. Here we aim to clarify the information content and function of Barbary macaque (Macaca sylvanus) copulation calls by testing (i) whether or not copulation calls advertise the female fertile phase and (ii) whether and how copulation ...
Rubio G José D - - 2008
The alimentary canal and the reproductive tract of males and females of Hypothenemus hampei Ferrari are described. The alimentary canal of H. hampei showed the crop with several spine-like structures and the midgut with few gastric caeca. We evidenced for the first time that adult females need to feed on ...
Astaras Christos - - 2008
We report preliminary findings on drill population ecology, feeding ecology, primate associations and conservation status in Korup National Park, Cameroon, based on analysis of data collected during 1,346 km (620 field hours) of trail patrols from February to June 2006. We encountered drills on 25 occasions and collected 304 fecal ...
Phong Tran Vu - - 2008
The fecundity and survival of 6 copepod species were assessed under laboratory conditions in order to choose the best candidates to control the aquatic stages of dengue mosquitoes in the field. Females of all the 6 species (Mesocyclops aspericornis, Mesocyclops pehpeiensis, Mesocyclops woutersi, Mesocyclops thermocyclopoides, Mesocyclops ogunnus, and Megacyclops viridis) ...
Wolovich Christy Kaitlyn - - 2008
Accounts of food sharing within natural populations of mammals have focused on transfers to offspring or transfers of food items that are difficult to obtain (such as meat). Five groups of socially monogamous owl monkeys (Aotus azarai azarai) in Formosa, Argentina were observed during 107 hr to determine the pattern ...
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