No data available that match "Ethology"
No data available that match "Ethology"
(1/45) Limits to the salience of ultraviolet: lessons from colour vision in bees and birds.
Ultraviolet is an important component of the photic environment. It is used by a wide variety of animals and plants in mutualistic communication, especially in insect and flower inter-relationships. Ultraviolet reflections and sensitivity are also becoming well considered in the relationships between vertebrates and their environment. The relative importance of ultraviolet vis a vis other primary colours in trichromatic or tetrachromatic colour spaces is discussed, and it is concluded that ultraviolet is, in most cases, no more important that blue, green or red reflections. Some animals may use specific wavebands of light for specific reactions, such as ultraviolet in escape or in the detection of polarised light, and other wavebands in stimulating feeding, oviposition or mating. When colour vision and, thus, the input from more than a single spectral receptor type are concerned, we point out that even basic predictions of signal conspicuousness require knowledge of the neuronal wiring used to evaluate the signals from all receptor types, including the ultraviolet. Evolutionary analyses suggest that, at least in arthropods, ultraviolet sensitivity is phylogenetically ancient and undergoes comparatively little evolutionary fine-tuning. Increasing amounts of ultraviolet in the photic environment, as caused by the decline of ozone in the atmosphere, are not likely to affect colour vision. However, a case for which ultraviolet is possibly unique is in the colour constancy of bees. Theoretical models predict that bees will perform poorly at identifying pure ultraviolet signals under conditions of changing illumination, which may explain the near absence of pure ultraviolet-reflecting flowers in nature. (+info)
(2/45) Comparative neuroethology of feeding control in molluscs.
Over the last 30 years, many laboratories have examined, in parallel, the feeding behaviour of gastropod molluscs and the properties of the nervous system that give rise to this behaviour. Equal attention to both behavioural and neurobiological issues has provided deep insight into the functioning of the nervous system in generating and controlling behaviour. The conclusions derived from studies on gastropod feeding are generally consistent with those from other systems, but often provide more detailed information on the behavioural function of a particular property of the nervous system. A review of the literature on gastropod feeding illustrates a number of important messages. (i) Many of the herbivorous gastropods display similarities in behaviour that are reflected in corresponding similarities in neural anatomy, pharmacology and physiology. By contrast, the same aspects of the behaviour of different carnivorous species are quite variable, possibly because of their specialised prey-capture techniques. Nonetheless, some aspects of the neural control of feeding are preserved. (ii) Feeding in all species is flexible, with the behaviour and the physiology adapting to changes in the current environment and internal state and as a result of past experience. Flexibility arises via processes that may take place at many neural sites, and much of the modulation underlying behavioural flexibility is understood at a systems and at a cellular level. (iii) Neurones seem to have specific functions that are consistent with their endogenous properties and their synaptic connections, suggesting that individual neurones code specific pieces of information (i.e. they are 'grandmother cells'). However, the properties of a neurone can be extremely complex and can be understood only in the context of the complete neural circuit and the behaviour that it controls. In systems that are orders of magnitude more complex, it would be impossible to understand the functional properties of an individual neurone, even if it also coded specific information. (iv) Systems such as gastropod feeding may provide a model for understanding the functional properties of more complex systems. (+info)
(3/45) Critical perspectives of animal agriculture: introduction.
The American Society of Animal Science has recently focused its attention on a variety of contentious issues in animal agriculture. This paper deals with critique, a philosophical approach to analyzing and understanding issues. This method has been employed by various contemporary philosophers. For example, feminist theorists have used this approach to critically analyze sexual harassment. Critique involves a critical analysis of the discourse (ideas or language) and practices that define the social reality in which we live. How we think about the world and how we behave in it determines how we humans interact with each other as well as with the rest of nature. This social structure is associated with power structures that benefit some individuals and harm others. In this paper, I demonstrate how critique can be used to better understand the social reality of animal agriculture. By analyzing certain popular texts in this field, I show that a "mechanical view of nature" is dominant in animal agriculture and argue that such a view contributes to a social reality that can be harmful to some humans and other animals. I conclude that various contentious issues can be better addressed when we engage in a critical analysis of this conceptual framework and base our analysis on the experiences of many different people, including those who have been harmed by our current system of animal agriculture. (+info)
(4/45) Innateness and the instinct to learn.
Concepts of innateness were at the heart of Darwin's approach to behavior and central to the ethological theorizing of Lorenz and, at least to start with, of Tinbergen. Then Tinbergen did an about face, and for some twenty years the term 'innate' became highly suspect. He attributed the change to Lehrman's famous 1953 critique in which he asserted that classifying behaviors as innate tells us nothing about how they develop. Although Lehrman made many valid points, I will argue that this exchange also led to profound misunderstandings that were ultimately damaging to progress in research on the development of behavior. The concept of 'instincts to learn', receiving renewed support from current theorizing among geneticists about phenotypic plasticity, provides a potential resolution of some of the controversies that Lehrman created. Bioacoustical studies, particularly on song learning in birds, serve both to confirm some of Lehrman's anxieties about the term 'innate', but also to make a case that he threw out the genetic baby with the bathwater. The breathtaking progress in molecular and developmental genetics has prepared the way for a fuller understanding of the complexities underlying even the simplest notions of innate behavior, necessary before we can begin to comprehend the ontogeny of behavior. (+info)
(5/45) Ethological and methodological considerations in the use of newborn rodents in biomedical research.
The use of newborn or immature animals in biomedical research poses certain challenges, in that the ecological niche of immature animals differs from that of adults, and the stimuli provided to immature animals can have profound physiological and behavioural effects through adulthood, even at the cerebral level. In particular, the newborn's behaviour and physiology are regulated by olfactory, thermal, and tactile stimulation supplied by the mother in the nest environment. Thus any disturbance to the mother-offspring relationship in the first two weeks of life can profoundly change the physiological and psychological state of the young. For this reason, research experiments must be adapted to the specific characteristics of the immature animal, to improve not only the quality of the data obtained but also the welfare of the animals. To this end, the present work provides some ethological and methodological considerations in the maintenance, handling, and testing of newborn rats and mice in biomedical research. (+info)
(6/45) Refining learning and memory assessment in laboratory rodents. An ethological perspective.
In neuroscientific research, the importance of a multi-level approach in studying behaviour, ranging from the molecular to the behavioural level, has been increasingly recognised. In fact, behaviour represents the ultimate output of the brain, and behavioural phenotyping may provide functional information that may not be detectable using molecular, cellular, or histological evaluations. To correctly exploit the study of behaviour in the field of neuroscience, the principles and strategies of ethology must be carefully considered, so as to design appropriate experiments and accurately interpret data. In particular, ethological-type scoring, which entails both the close observation of the studied behaviour and the taking into account of its possible evolutionary history and adaptive significance, can contribute to standardising experimental protocols, so as to improve the quality of data and the welfare of the experimental animal. (+info)
(7/45) Refinement techniques in experimental protocols involving Callitrichids.
The invasiveness of biomedical experiments on laboratory animals should be limited to the greatest extent possible yet without sacrificing the quality of the data collected. To this end, refinement techniques can be used. In the present work, we describe some of these techniques, focussing on the familiarity of the experimental environment, alternative sampling techniques (including the use of positive training), telemetry, and methods for improving ethological experiments. As a model, we have chosen the common marmoset (Callithrix jacchus), which is frequently used in biomedical research. (+info)
(8/45) Ethology and the biological correlates of mood.
The insights of ethology-the science of animal behavior from a biological and psychological point of view-were incorporated in the 1950s by the British developmental psychiatrist, John Bowlby, into his attachment theory, which argued that a secure affective base in infancy was critical to the normal development of perception, cognition, learning, and emotion, in addition to that of physical parameters. The theory was illustrated by Harlow's pioneering experiments with baby monkeys: those raised with a wire-frame "mother" failed to thrive, compared with the more normal development of those deriving comfort contact from a terry-cloth surrogate. Modern neuroscience techniques have confirmed that the absence of sensory stimulation during periods of maximal synaptic expansion provides the substrate for a subsequent mood disorder. Ethology offers a novel "nature plus nurture" approach to the development of abnormal mood, as well as a target for treatment. (+info)