AN INTRODUCTION TO BEHAVIOURAL ECOLOGY 4TH EDITION PDF
An Introduction to Behavioural Ecology, 4th Edition by Davies, Nicholas B., Krebs , John R. and West, Stuart A.. Wiley‐Blackwell, Oxford, This textbook helped to define the field of Behavioural Ecology. In this fourth edition the text has been completely revised, with new chapters and many new. PDF | On Mar 1, , Nick J. Royle and others published An However,. as this new, fourth, edition of An Introduction to Behavioural Ecology.
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Author: Nicholas B. Davies Pages: Publication Date Release Date ISBN: Product Group:Book Download. Editorial Reviews. Review. “Altogether this is an excellent introductory text, with full and An Introduction to Behavioural Ecology 4th Edition, Kindle Edition. An Introduction to. Behavioural Ecology. Nicholas B. Davies, John R. Krebs and Stuart A. West. FOURTH EDITION. A John Wiley & Sons, Ltd., Publication.
This point is nowhere better illustrated than by George Orwell in his brilliant essay 'Politics and the English Language' He translates the following well-known verse from Ecclesiastes into modern English: 'I returned and saw under the sun, that the race is not always to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favour to men of skill; but time and chance happeneth to them all.
While we cannot hope to emulate the clarity and brilliance of the writer of Ecclesiastes, or indeed of George Orwell, we hope we have avoided the worst excesses of the Orwellian parody and presented our ideas in simple but precise language.
Chapter 1. Natural Selection, Ecology and Behaviour Questions about behaviour In this book we will explore the relationships between animal behaviour, ecology and evolution. We shall describe how animals behave under particular ecological conditions and then ask 'Why has this behaviour evolved? Why do some birds have songs consisting of pure whistles while others produce buzzes and trills? We shall also ask some precise, quantitative questions such as why do great tits lay clutches of 8 eggs and why does the male dungfly copulate for on average 41 min?
Niko Tinbergen, one of the founders of ethology, emphasized that there are several different ways of answering the question 'Why? These have come to be known as Tinbergen's four questions Tinbergen For example, if we asked why starlings, Sturnus vulgaris, sing in the spring, we could answer as follows.
Starlings sing to attract mates for breeding. Because increasing daylength triggers off changes in hormone levels in the body, or because of the way air flows through the syrinx and sets up membrane vibrations.
These are answers about the internal and external factors which cause starlings to sing. Starlings sing because they have learned the songs from their parents and neighbours. This answer would be about how song had evolved in starlings from their avian ancestors. The most primitive living birds make very simple sounds, so it is reasonable to assume that the complex songs of starlings and other song birds have evolved from simpler ancestral calls.
It is important to distinguish these various kinds of answer or otherwise time can be wasted in sterile debate. If someone said that swallows migrate south in the autumn because they are searching for richer food supplies while someone else said they migrated because of decreasing daylength, it would be pointless to argue about who was correct.
Both answers may be right: the first is in terms of survival value or function and the second is in terms of causation.
It is these two answers that are the most frequently muddled up and so to make the distinction clear we will discuss an example in detail.
The group defends a territory in which it hunts for prey, especially gazelle and zebra. Within a pride all the females are related; they are sisters, mothers and daughters, cousins, and so on. All were born and reared in the pride and all stay there to breed. Females reproduce from the age of 4 to 18 years and so enjoy a long reproductive life.
For the males, life is very different. When they are 3 years old, young related males sometimes brothers leave their natal pride. After a couple of years as nomads they attempt to take over another pride from old and weak males. After a successful takeover they stay in the pride for 2 to 3 years before they, in turn, are driven out by new males.
A male's reproductive life is therefore short. The lion pride thus consists of a permanent group of closely related females and a smaller group of separately interrelated males present for a shorter time.
We will consider three interesting observations about reproductive behaviour in a pride Bertram The mechanism, or causal explanation, may be the influence of an individual's pheromones on the oestrus cycles of other females in the pride.
A similar phenomenon occurs in schools, where girls living in the same dormitory may also synchronize their menstrual cycles, perhaps due to the effect of pheromones McClintock The function of oestrus synchrony in lionesses is that different litters in the pride are born at the same time and cubs born synchronously survive better.
This is because there is communal suckling and with all the females lactating together a cub may suckle from another female if its mother is out hunting Fig. In addition, with synchronous births there is a greater chance that a young male will have a companion when it reaches the age at which it leaves the pride.
With a companion a male is more likely to achieve a successful take-over of another pride Bygott et al.
Bottom: a female suckles her sister's cub alongside her own. She is on heat for 2 to 4 days during which time she copulates once every 15min throughout the day and night. Despite this phenomenal rate of copulation the birth rate is low. Even for those cubs that are born, only 20 per cent will survive to adulthood.
It can be calculated that there are copulations for each offspring that attains the adult stage. But why are females designed in this apparently inefficient way? One hypothesis is that it may be advantageous to the female to be receptive even at times when conception is unlikely, because this means that each copulation is devalued. For a male there is only a 1 : chance that a given copulation will produce a surviving cub and so it is not worth fighting with other males in the pride over a single mating opportunity.
Given that males may also kill cubs that are not their own see below , it may pay a female to mate with all the males in the pride to increase paternity uncertainty. Ideally a female may give each male a sufficient chance of being the father of her cubs that it does not pay him to kill them!
The causal explanation for this behaviour may be the unfamiliar odour of the cubs which induces the male to destroy them. A similar effect, known as the Bruce Effect, occurs in rodents where the presence of a strange male prevents the implantation of a fertilized egg or induces abortion. The advantage of the infanticide for the male that takes over the pride is that killing the cubs fathered by a previous male brings the female into reproductive condition again much quicker and so hastens the day that he can father his own offspring.
If the cubs were left intact then the female would not come into oestrus again for 25 months. By killing the cubs she becomes ready for mating after only 9 months. Remember that a male's reproductive life in the pride is short, so any individual that practises infanticide when he takes over a pride will father more of his own offspring and therefore the tendency to commit infanticide will spread by natural selection.
Interestingly, the heightened sexual activity of the females is most marked during the first few months after a take-over. The females play an active role in soliciting copulations from several males and this appears to elicit competition between different male coalitions for the control of the pride, with the result that larger coalitions eventually become resident.
This is of adaptive advantage to the female because she needs protection from male harassment of her cubs for over 2 years in order to rear her cubs successfully 3. The differences between the causal and functional explanations of these three aspects of reproductive behaviour in the lions are summarized in Table 1.
Natural selection Throughout this book we will be focusing on functional questions about behaviour. Our aim is to try and understand how an animal's behaviour is adapted to the environment in which it lives. When we discuss adaptations we are referring to changes brought about during evolution by the process of natural selection. For Charles Darwin, adaptation was an obvious fact.
It was obvious to him that eyes were well designed for vision, legs for running, wings for flying and so on. What he attempted to explain was how Table 1.
Take-overs by males Better cub survival Young males survive better and have greater reproductive success when they leave pride if in a group 2 High rate of copulation Female infertility Time of ovulation concealed Each copulation of less value to a male Increased paternity uncertainty may protect cubs from males Elicits competition between male coalitions, so females get best protectors taking over pride 3 Young dic whcn new males take ovcr pride Abortion?
His theory of natural selection, published in the Origin of Species in , can be summarized as follows. This capacity is not realized because the number of individuals within a population tends to remain more or less constant over time. Therefore there must be competition between individuals for scarce resources such as food, mates and places to live. These will inherit the characteristics of their parents and so evolutionary change will take place by natural selection.
The individuals that are selected will be those best able to find food and mates, avoid predators and so on. When Darwin formulated his idea he had no knowledge of the mechanism of heredity. The modern statement of the theory of natural selection is in terms of genes. Although selection acts on differences in survival and reproductive success between individual organisms, or phenotypes, what changes during evolution is the relative frequency of genes.
We can restate Darwin's theory in modern genetic terms as follows. These proteins regulate the development of the nervous system, muscles and structure of the individual and so determine its behaviour.
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These will cause differences in development and so there will be variatio-n within a population. Natural selection is the differential survival of alternative alleles. The individual can be regarded as a temporary vehicle or survival machine by which genes survive and are replicated Dawkins Because selection of genes is mediated through phenotypes, the most successful genes will be those which promote most effectively an individual's survival and reproductive success and that of relatives, see later.
As a result we would therefore expect individuals to behave so as to promote gene survival. Before we discuss how thinking about genes can help us to understand the evolution of behaviour, we should examine the evidence that gene differences can cause differences in behaviour. Genes and behaviour Behavioural ecology is concerned with the evolution of adaptive behaviour in relation to ecological circumstances. Natural selection can only work on genetic differences and so for behaviour to evolve a there must be, or must have been in the past, behavioural alternatives in the population, b the differences must be, or must have been, heritable; in other words a proportion of the variation must be genetic in origin, and c some behavioural alternatives must confer greater reproductive success than others.
Three main methods have been used to study the ways in which genes influence behaviour. In one mutant, known colourfully as 'stuck', the male fails to disengage from the female after the normal min period of copulation. Mutation of another gene produces 'coitus interruptus' males which disengage after only 10min and fail to produce any offspring. Benzer was able to trace the cause of these mutations and show that they resulted from abnormalities in the sensory receptors, nervous system or muscles of the flies.
Normal Drosophila learn to selectively avoid an odour which is associated with an electric shock. Mutant 'dunce' flies do not learn to avoid the shock though they show normal behaviour in other respects and can learn visual tasks. Dunce flies are produced by an abnormality of a complex gene, at least part of which codes for the enzyme cyclic AMP phosphodiesterase, which breaks down the intracellular second messenger CAMP.
This suggests that the enzyme is necessary for associative learning. Other learning mutants, such as 'amnesiac', which learns normally but forgets very rapidly, have also been isolated. In all cases the mutations perturb second messenger systems Dudai For example, Aubrey Manning was able to select for two different mating speeds in the fruit fly, Drosophila melanogaster, by selectively breeding from fast and slow maters.
Such selection experiments nearly always work, showing that much of the continuous phenotypic variation seen in populations has some genetic basis.
Another example is provided by male field crickets, Gryllus integer, which either call to attract females or silently intercept females attracted to the callers. Cade was able to select for males which called a lot and those which called only rarely, thus showing that variation in calling duration had a genetic component. Stevan Arnold 1 studied the garter snake, Thamnophis efegans, in the south-west United States. Inland populations are very aquatic and commonly feed underwater on frogs, fish and leeches.
Coastal populations are terrestrial foragers and mainly eat slugs. In laboratory choice experiments it was found that wild-caught inland snakes refused to eat slugs, though the coastal ones readily accepted them. Tests with naive newborn snakes showed that 73 per cent of the coastal individuals attacked and ate slugs while only 35 per cent of the inland snakes did so.
Young snakes are incubated inside their mother and so one possibility is that the mother's diet could influence the young directly. Arnold arranged matings between inland and coastal individuals and found that the offspring tended to show an intermediate incidence of slug eating.
They did not tend to resemble their mother as opposed to their father and so the influence of maternal diet can be ruled out. These results suggest that differences in food preference are correlated with genetic differences, and that garter snakes in different areas have been selected to respond to different prey types. Most species of warblers are summer visitors to Europe.
If individuals are kept in a cage, they show a period of 'restlessness' in the autumn which corresponds with the time at w h c h they would migrate south to Africa for the winter. Quantitative comparisons of the nocturnal restlessness of caged experimental birds showed that the duration of the restlessness correlated well with the distance which the individuals migrated.
Peter Berthold Berthold et al. Blackcaps are ideal for such a study because different populations show differing degrees of migratory behaviour: in southern Germany, for example, all birds migrate, in southern France only a part of the population migrates, and in the Cape Verde Islands, the population is entirely sedentary. To what extent do these inter-population differences reflect genetic differences?
Berthold has investigated this question by two kinds of experiment: cross-breeding of birds from different populations, and selection experiments. Both kinds of study involved breeding blackcaps in captivity and studying the migratory behaviour of offspring in cages equipped with electronic perches to record migratory restlessness.
Hybrids between parents from southern Germany migratory and the Cape Verde Islands resident had intermediate behaviour. About 40 per cent of the offspring showed migratory restlessness and the remainder did not. Furthermore, the preferred average directional heading shown by the migratory hybrid offspring was indistinguishable from that of the German parents.
These results show that the difference between the two populations has a genetic basis. They suggest that more than one gene is involved otherwise the offspring would all resemble the dominant parent and that the effect of several genes is likely to have a threshold effect otherwise all offspring would be intermediate between the two parents.
Berthold's selection experiments also confirm a genetic basis to differences in migratory behaviour. Among hand-raised blackcaps from a population in the Rhone Valley of southern France, three-quarters were migratory and one-quarter resident, when tested in the laboratory.
By selectively breeding from migratory and non-migratory parents, Berthold was able to produce strains of blackcaps that were either per cent migratory in three generations or per cent residents in six generations Fig. Thc numbers indicate how many birds wcrc hand-raiscd in each generation. Starting from a parcntal stock in which about 75 per cent of birds migratc, the sclcction expcriment produced a population of non-migrators in six generations, and another linc of migrators in thrcc gcncrations.
In cach gcneration, half thc pairs wcre first-ycar birds and half wcrc mixcd first-ycar X oldcr bird pairs.
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Notc that thc vcrtical axis of thc graph has a rcvcrscd scalc. These various examples show that genetic differences between individuals can lead to differences in behaviour matingbehaviour, learning, singing, foraging and migration. Three points need to be emphasized. First, when we talk about 'genes forJ a particular structure or behaviour, we do not imply that one gene alone codes for the trait. Genes work in concert and it is likely that many genes together will influence an individual's mating preference, foraging habits and migration patterns.
However, a difference in behaviour between two individuals may be due to a difference in one gene. A useful analogy is the baking of a cake.
A difference in one word of a recipe may mean that the taste of the whole cake is different, but this does not mean that the one word is responsible for the entire cake Dawkins Whenever we talk about 'genes for' certain traits this is shorthand for gene differences bringing about differences in behaviour.
Second, genes will often influence behaviour in simple ways. Gene differences can result in behavioural differences because genes code for enzymes which influence the development of the sensory, nervous and muscle systems of the animal which in turn affect its behaviour. For example, a gene could influence a moth's preference for a particular background by coding for certain visual pigments in the eye.
Third, just because it can be shown that genes influence behaviour this does not imply that genes alone produce the behaviour, or even that the behaviour can be usefully divided up into genetic and environmental components.
The way in which behaviour develops is the result of a complex interaction between genes and environment. Imagine, for example, that a behavioural ecologist comes across the nest of a long tailed tit Aegithalos caudatus. He or she would be immediately impressed by how well the nest was adapted to the bird's way of life, the wonderful crypsis of the nest, its strength and warmth.
There are three different ways in which this adaptation could develop in an individual Bateson Individuals could all learn by trial and error how to build good nests.
Alternatively they could copy another, more experienced bird. Finally, during evolution genes necessary for the expression of actions leading to the construction of good nests could have spread through the population by natural selection because individuals building the best nests would have left most young. Thus, all individuals may be able to build good nests without practice or observing others. However, even if nest building required learning for its proper development, genetic differences in learning ability may still be involved in its evolution.
Selfish individuals or group advantage? We now return to our theme of studying the adaptive significance of behaviour, how it contributes to an individual's chances of survival and its reproductive success. We interpreted the behaviour of the lions in relation to individual advantage, reflecting Darwin's emphasis on evolution as a struggle between individuals to outcompete others in the population.
Many traits evolve because of their advantage to the individual even though they are disadvantageous to others in the population. For example, it's not to the species' advantage to have a cub killed when a new male takes over a lion pride.
It's not to the lionesses' advantage either! However, she is smaller than the male and there is probably not much that she can do about it. WordPress Shortcode.
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West Pages: Paperback Brand: Description Additional resources for this book can be found at: In this fourth edition the text has been completely revised, with new chapters and many new illustrations and full colour photographs. The theme, once again, is the influence of natural selection on behaviour -- an animal's struggle to survive and reproduce by exploiting and competing for resources, avoiding predators, selecting mates and caring for offspring, -- and how animal societies reflect both cooperation and conflict among individuals.
Stuart A. West has joined as a co- author bringing his own perspectives and work on microbial systems into the book. Written in the same engaging and lucid style as the previous editions, the authors explain the latest theoretical ideas using examples from micro-organisms, invertebrates and vertebrates.
There are boxed sections for some topics and marginal notes help guide the reader. The book is essential reading for students of behavioural ecology, animal behaviour and evolutionary biology. Key Features: Long-awaited new edition of a field-defining textbook New chapters, illustrations and colour photographs New co-author Focuses on the influence of natural selection on behavior, and how animal societies reflect both cooperation and conflict among individuals "The long-awaited update to a classic in this field is now here, presenting new direc-tions in thinking and addressing burning questions.
Richly informed by progress in many other disciplines, such as sensory physiology, genetics and evolutionary theory, it marks the emergence of behav-ioural ecology as a fully fledged discipline This is a marvellous book, written in a lucid style.Had lots of blurbs about specific animal behaviors and taught behavioral ecology well.
Ideally a female may give each male a sufficient chance of being the father of her cubs that it does not pay him to kill them! The way in which behaviour develops is the result of a complex interaction between genes and environment. There are many examples of parent-offspring conflict in nature.
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