About this title This new edition of Animal Behavior has been thoroughly rewritten with coverage of much recent work in animal behavior. The scope of the changes for the tenth edition, however, is much more all-encompassing than that of past revisions. Thoughtful suggestions from many readers inspired a major reorganization of the material, such that the new book presents the central concepts of animal behavior in a different sequence from prior editions: The Theory of Evolution by Natural Selection. Instead of introducing the concept of proximate and ultimate causation and then focusing heavily on the proximate mechanisms of behavior in the early chapters, this edition focuses first on the evolutionary basis of behavior. Chapter 1 presents the concept of a Darwinian puzzle, a trait that exists even though it seems to reduce the reproductive success of individuals, in which case it should have been eliminated by natural selection.
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But I came away certainly thinking genes do determine behavior to a large extent, depending on how you think about it. A single gene in fruit fly larvas make them either sit in one spot, or rove about. A single gene in mice affects hippocampus development which underlies the differences in spatial memory performance.
Knocking out the fosB gene in mice makes them indifferent to their young. Again, Alcock would say genes code for proteins and enzymes, which make hormones which develop certain neuron pathways and structures. Then seven weeks after ejaculation have passed they return to infanticidal behavior. This seems to be an adaptation to destroy rival offspring during the three weeks of pregnancy, and by the time seven weeks have passed their own young will have dispersed and the infanticidal behavior can resume.
Scientists have found that by "speeding up" the number of days the mice think have passed using artificial lighting, they could cause the mice to attack young or not, showing that it is based to some extent on an internal clock, and corroborated by environmental cues about time passage.
In one case researchers re-routed the optical nerve in an infant ferret to the auditory cortex of the brain, and it actually developed as a second visual cortex. The genes in the cells responded to the visual messages and developed along that pathway. Some species have learned to exploit this in others. The rover beetle uses an attractant pheromone normally used by other ants. This causes ants to accept its larva into their brood chambers, which proceeds to eat the ant eggs.
The direction they fly in appears to be mostly gene-determinate although singing interestingly is learned in some species, leading to local "dialects. It makes perfect sense, but is still so weird. The testes of most birds shrink during non-breeding seasons as well.
It makes sense from an efficiency standpoint. Step-children are more often abused, mothers of step-children and adopted children spend less on food. These could be maladaptive by-products of the previously adaptive trait of treating genetic offspring favorably.
Infanticide and rape are covered in some detail. Of course Alcock is not trying to justify any of this, just explain why it happens from an evolutionary perspective.
You really start to question what behaviors you have that are remotely "yours. I liked the pervasive cost-benefit analysis that comes up in later chapters. Crows fly to the exact optimal height for dropping and breaking open whelks to eat, not wasting energy flying higher than needed.
Some birds are able to regulate the sex of their offspring, depending on the quality of the territory they inhabit. Better territory dictates more females who may stay around to help with the next brood, but for birds living in a poor territory a female is another mouth to feed.
There is a cost of exaggerated begging in a brood of baby chicks in that they deprive their siblings of food, and harm the reproductive success of someone they share genes with. So the degree to which individuals moderate their begging behavior is a function of the degree of relatedness among the nestmates. It has been found, as predicted that broods of mixed parentage are louder than broods of monogamous species where the children share more genes.
This gets more complicated when Alcock delves into how altruism appears as a function of helping those related to you. It gets even more complicated with "eusocial" species which have whole non-reproductive castes who are helpers, foragers, defenders, etc. Species of this type are usually haplodiploid. This is when eggs destined to be males are unfertilized and so the male gets only one set of chromosomes, not two, nothing from the father.
This high degree of relatedness due to haplodiploidy is used to explain eusocial, self-sacrificing behavior in many species. An interesting aside -- these sister wasps share LESS relatedness with their brothers. As predicted, this means the sisters help feed their brothers less.
Nature starts to look like one big mathematical calculation, but it makes sense. But the focuses of these two books are quite different. For example; hypothesis: A resident defends his territory more strongly than a rival will try to take it because he has more to lose than the rival, not only the resources of the territory, but the time put into creating relationships with neighbors which saves them time and energy engaging in struggles. Prediction: The probability a territory holder that is experimentally removed and later released will reclaim his territory is a function of how long the replacement has occupied the site in his place -- this is true.
Another hypothesis: Nesting colonies of foraging birds serve as an "information center" and others will follow those who have recently found food. Prediction: If info is shared they will leave together and follow in the same direction -- this is true. Of course I would love to see what experiments have been done in intervening years to corroborate or refute various theories, or clear up a few questions here and there which are left uncertain.
But those new textbooks are so pricey!
Animal Behavior: An Evolutionary Approach
ISBN 13: 9780878939664