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Results 201 - 250 of 913
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Teder Tiit - - 2010
Within a season, successive generations of short-lived organisms experience different combinations of environmental parameters, such as temperature, food quality and mortality risk. Adult body size of e.g. insects is therefore expected to vary both as a consequence of proximate environmental effects as well as adaptive responses to seasonal cues. In ...
Hill Kim - - 2009
Evolutionary researchers have recently suggested that pre-modern human societies habitually practised cooperative breeding and that this feature helps explain human prosocial tendencies. Despite circumstantial evidence that post-reproductive females and extra-pair males both provide resources required for successful reproduction by mated pairs, no study has yet provided details about the flow ...
Tanaka Masayuki - - 2009
Chimpanzees can flexibly use tokens in cognitive tasks, but it is still unknown if they can share and/or compete over tokens as they do for food. This study aimed to evaluate the interactions spontaneously occurring between mother and offspring chimpanzees when tokens exchangeable for food were provided. Forty tokens were ...
Lane Jeffrey E - - 2010
1. The assumption that the primary limitations on reproductive success differ between the sexes is inherent in traditional sexual selection theory. Although the energy that can be allocated to reproduction is assumed to be the main limitation to females, the ability to attract and defend oestrous females is assumed to ...
Wootton R J - - 2009
An experiment quantified the effect of food ration and spawning number on the breeding season reproductive performance of batch-spawning, female three-spined sticklebacks Gasterosteus aculeatus. Individually housed females were maintained on fixed rations of 2, 4, 8 or 16% of their initial postspawning mass of live enchytraeid worms from immediately after ...
Chancellor Rebecca L - - 2009
Authors of socioecological models propose that food distribution affects female social relationships in that clumped food resources, such as fruit, result in strong dominance hierarchies and favor coalition formation with female relatives. A number of Old World monkey species have been used to test predictions of the socioecological models. However, ...
Christiansen Sofie - - 2009
By disrupting the action of androgens during gestation, certain chemicals present in food, consumer products, and the environment can induce irreversible demasculinization and malformations of sex organs among male offspring. However, the consequences of simultaneous exposure to such chemicals are not well described, especially when they exert their actions by ...
Fruteau Cécile - - 2009
Animals neither negotiate verbally nor conclude binding contracts, but nevertheless regularly exchange goods and services without overt coercion and manage to arrive at agreements over exchange rates. Biological market theory predicts that such exchange rates fluctuate according to the law of supply and demand. Previous studies showed that primates pay ...
Colby Sarah E - - 2009
This study aimed to explore Mexican dietary acculturation patterns among immigrants using a unique transnational photographic assessment. Participants (N = 10) were Latino mother and child pairs living in Mexico (1 pair) and in the United States (4 pairs). Data were collected in 2 phases: 1) participant observation and photography ...
Griffith Leslie C - - 2009
Mechanisms for identifying appropriate mating partners are required for any species to survive. In many types of animals, males employ multiple sensory modalities to initially search for females and to subsequently determine if they are fit and/or receptive. In this paper we will detail the multiple types of sensory information ...
Zur Tamar - - 2009
Previous studies have suggested that social interactions (e.g., the actions and reactions elicited by the interaction of co-specific individuals) induce individual fruit flies (Tephritidae) to ingest more food, especially protein-rich food. Changes in feeding behavior related to social interactions have been associated with reproduction (e.g., when different sexes are present), ...
Heiss Rebecca S - - 2009
In urbanized areas, many adult birds find sufficient foods to survive, but the anthropogenic foods that are abundant there may be detrimental to nestling growth. In fact, American Crow (Corvus brachyrhynchos) nestlings are smaller in suburban than rural areas, possibly because of nutrient limitation. Here, we seek to identify possible ...
Zanette Liana - - 2009
Food-supplemented parents typically produce more offspring, as numerous experiments on vertebrate populations have shown. 'Propagule' (egg or neonate) size and parental care may also be affected, with implications concerning the adult quality of offspring, although few experiments have addressed whether food-supplementing one generation affects adult quality in the next. We ...
Mas Flore - - 2009
Begging signals of offspring are condition-dependent cues that are usually predicted to display information about the short-term need (i.e. hunger) to which parents respond by allocating more food. However, recent models and experiments have revealed that parents, depending on the species and context, may respond to signals of quality (i.e. ...
Nord Andreas - - 2009
We evaluated biotic and abiotic predictors of rest-phase hypothermia in wintering blue tits (Cyanistes caeruleus) and also assessed how food availability influences nightly thermoregulation. On any given night, captive blue tits (with unrestricted access to food) remained largely homeothermic, whereas free-ranging birds decreased their body temperature (T(b)) by about 5 ...
Furuichi Takeshi - - 2009
Differences in party size and cohesiveness among females have been primary topics in socio-ecological comparisons of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). This paper aims to review previous studies that attempted to explain these differences and propose some hypotheses to be tested in future studies. Comparisons of recent data ...
Bartelt Robert J - - 2009
The lesser mealworm beetle, Alphitobius diaperinus (Panzer), is a widespread serious pest in poultry production facilities and is difficult to control by conventional means. Although pheromone-based tools have become useful in the management of other beetle pests, no pheromone was known for A. diaperinus, and this study sought to develop ...
Speller, Stanley Wayne
This study of breeding arctic foxes (<u>Alopex</u> <u>lagopus</u>) and their major prey, the brown lemming (<u>Lemmus</u><u> trimucronatus</u>) and the Greenland­ collared lemming (<u>Dicrostonyx</u><u> groenlandicus</u>), was conducted at Aberdeen Lake, District of Keewatin, N.W.T. in the summers of 1968, 1969 and 1970. <p> Lemming trapping showed that the density of both ...
Watts Heather E - - 2009
Mammalian societies in which females dominate males are rare, and the factors favouring the evolution of female dominance have yet to be clearly identified. We propose a new hypothesis for the evolution of female dominance and test its predictions with empirical data from the spotted hyena (Crocuta crocuta), a well-studied ...
Boncoraglio Giuseppe - - 2009
Kin selection theory predicts that, in species where progeny members compete for limiting parental care, individual offspring should be more prone to monopolize parental resources as their genetic relatedness to brood competitors decreases. Mixed parentage among broodmates may arise as a consequence, for example, of extra-pair fertilization or brood parasitism ...
Sherry David F - - 2009
Food storing is seasonal in birds like chickadees, nuthatches and jays, occurring at high levels in fall and winter and low levels in spring and summer. Memory for cache sites is hippocampus dependent in chickadees and both the recruitment of new neurons into the hippocampus and the total size of ...
Brouwer Lyanne - - 2009
Temporal variation in survival, fecundity, and dispersal rates is associated with density-dependent and density-independent processes. Stable natural populations are expected to be regulated by density-dependent factors. However, detecting this by investigating natural variation in density is difficult because density-dependent and independent factors affecting population dynamics may covary. Therefore, experiments are ...
Mainwaring Mark C - - 2009
Parental investment in reproduction is generally limited by food availability, and so avian life-history research has traditionally focused on the brood rearing phase, when food requirements are greatest. Only relatively recently has the focus extended to the incubation phase, and even more recently to the nest-building phase, where observational and ...
Gurven Michael - - 2009
The role of men in hunter-gatherer societies has been subject to vigorous debate over the past 15 years. The proposal that men hunt wild game as a form of status signaling or "showing off" to provide reproductive benefits to the hunter challenges the traditional view that men hunt to provision ...
Prasad S K - - 2009
This study was designed to test whether Mucuna pruriens, a natural source of l-dihydroxyphenylalanine (l-DOPA, a dopamine precursor) feeding, can influence development and reproductive conditions in the high food value bird, Japanese quail, Coturnix coturnix japonica. Experiments were performed in both male and female Japanese quail. One-week-old quail chicks were ...
Knudsen, Jens W
It was the aim of this research project to study the growth and reproductive cycles of the Puget Sound Brachyura and Anomura as they are related to oceanographic and environmental conditions. These goals were designed to answer many of the basic questions concerning the local crab population and to serve ...
Battisti David S - - 2009
Higher growing season temperatures can have dramatic impacts on agricultural productivity, farm incomes, and food security. We used observational data and output from 23 global climate models to show a high probability (>90%) that growing season temperatures in the tropics and subtropics by the end of the 21st century will ...
Byrne Phillip G - - 2009
Sequential polyandry may evolve as an insurance mechanism to reduce the risk of choosing a mate that is infertile, closely related, genetically inferior or incompatible, but polyandry also might insure against nest failure in unpredictable environments. Most animals are oviparous, and in species where males provide nest sites whose quality ...
López-Bao José V - - 2009
BACKGROUND: As a conservation tool, supplementary feeding programs may be directed to specific individuals or sectors of the target population whose productivity or survival is thought to be limited by food scarcity. However, the use of supplemental food by different sex and age classes has received little attention. We studied ...
Budki Puja - - 2009
In a seasonally breeding bird species, food deprivation affects reproduction. A key question is whether food shortage at any time in the year will affect reproduction even though the food supply subsequently becomes adequate. A prediction would be that a food supply that is of shorter duration than that optimally ...
Bridge Eli S - - 2009
Florida Scrub-Jays (Aphelocoma coerulescens) in a suburban environment with year-round access to multiple sources of abundant, human-source foods consistently breed earlier each year and have lower baseline levels of circulating corticosterone (CORT) than jays in a nearby wildland setting. These findings suggest that food supplies influence CORT levels, which in ...
Silva M C - - 2009
We examined the influence of climate and man on size and fluctuating asymmetry in two species of Euglossine bees collected from a semideciduous forest reserve. Sixty males of each species were collected; four measurements were made of their wings to obtain a multivariable size index and a fluctuating asymmetry index. ...
Gould L - - 2009
Primates vary in their choice or avoidance of plant foods high in condensed tannins (CT). Our study focused on CT intake in two groups of Lemur catta residing in spiny forest habitat during two reproductive periods. We examined whether L. catta in this habitat avoided plant foods high in CT, ...
KwieciƄski Zbigniew - - 2009
Sex differences in digestive performance may be related to food contents, to body size as well as many other physiological traits. However, evidence for sex differences in the digestion of birds, especially in the case of predators, is scarce. Therefore we studied digestive efficiency, and also body size, intestine length ...
Tajedin L - - 2009
Many microorganisms in midgut of mosquito challenge with their host and also other pathogens present in midgut. The aim of this study was presence of non-pathogens microorganisms like fungal flora which may be crucial on interaction between vectors and pathogens. Different populations of Anopheles stephensi were reared in insectary and ...
Caldwell Gary S - - 2009
Diatoms are one of the main primary producers in aquatic ecosystems and occupy a vital link in the transfer of photosynthetically-fixed carbon through aquatic food webs. Diatoms produce an array of biologically-active metabolites, many of which have been attributed as a form of chemical defence and may offer potential as ...
Bonadonna Francesco - - 2009
Chemical signals can yield information about an animal such as its identity, social status or sex. Such signals have rarely been considered in birds, but recent results have shown that chemical signals are actually used by different bird species to find food and to recognize their home and nest. This ...
Nätt Daniel - - 2009
Environmental challenges may affect both the exposed individuals and their offspring. We investigated possible adaptive aspects of such cross-generation transmissions, and hypothesized that chronic unpredictable food access would cause chickens to show a more conservative feeding strategy and to be more dominant, and that these adaptations would be transmitted to ...
Liu Wan-chun - - 2009
Vocal learning has evolved in only a few groups of mammals and birds. The developmental and evolutionary origins of vocal learning remain unclear. The imitation of a memorized sound is a clear example of vocal learning, but is that when vocal learning starts? Here we use an ontogenetic approach to ...
Ratcliff William C - - 2009
Stresses like dietary restriction or various toxins increase lifespan in taxa as diverse as yeast, Caenorhabditis elegans, Drosophila and rats, by triggering physiological responses that also tend to delay reproduction. Food odors can reverse the effects of dietary restriction, showing that key mechanisms respond to information, not just resources. Such ...
Bauchinger Ulf - - 2009
Long-distance migratory passerines initiate testicular recrudescence during spring migration to meet the demands of timely reproduction upon immediate arrival on the breeding grounds. The degree of testicular development is known to depend on environmental factors like stopover habitat quality; reproductive performance may be strongly impacted by testicular maturation upon arrival ...
Pontzer Herman - - 2009
Most animals must travel to find food, incurring an unavoidable energy and time cost. Economic theory predicts, and experimental work confirms, that within species, increasing the distance traveled each day to find food has negative fitness consequences, decreasing the amount of energy invested in maintenance, repair, and reproduction. Here, we ...
Martel Kristine L - - 2009
We previously found that female mice exhibited Fos responses in the accessory olfactory bulb (AOB) after exposure to volatile opposite-sex, but not same-sex, urinary odours. This effect was eliminated by lesioning the main olfactory epithelium, raising the possibility that the AOB receives information about gender via centrifugal inputs originating in ...
Barrios Arantza A Department of Molecular Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA. - - 2008
How do animals integrate internal drives and external environmental cues to coordinate behaviors? We address this question by studying mate-searching behavior in C. elegans. C. elegans males explore their environment in search of mates (hermaphrodites) and will leave food if mating partners are absent. However, when mates and food coincide, ...
Dewhirst Sarah Y - - 2008
The sex pheromones of many aphid species from the subfamily Aphididae comprise a mixture of the iridoids (cyclopentanoids) (1R,4aS,7S,7aR)-nepetalactol and (4aS,7S,7aR)-nepetalactone. In this paper, we investigate whether other chemicals, in addition to nepetalactol and nepetalactone, are released from Dysaphis plantaginea (rosy apple aphid) oviparae as part of their sex pheromone. ...
Daramola J O - - 2009
West African Dwarf (WAD) goats are widely distributed in the subhumid and humid zones of Africa but are particularly associated with less favourable environments. Adaptive features such as feeding behaviour, efficiency of feed use and disease tolerance enable WAD goats to thrive on natural resources left untouched by other domestic ...
Fordham, Robin Alexander
An account is given of ecological studies on the Southern Black-backed Gull Larus dominicanus Licht in which attention is directed to the structure and balance of the Wellington population. This population is large; in the 1963-64 season more than 5,600 pairs were breeding in the study area, and the peak ...
Gregory Stephen David - - 2009
Endemic Nesoryzomys swarthi and invasive Rattus rattus exist in unlikely sympatry in Galápagos as female N. swarthi suffer from competition with R. rattus. This study evaluates the role of feeding habits in facilitating their co-occurrence. Spool-and-line tracking of 85 N. swarthi and 33 R. rattus was used to quantify their ...
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 ...
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