Behavioral Ecology (Chapter 53) The study of how the actions of animals affect their survival and reproductive success. Most animal behavior is innate (instinctive). This means it’s controlled by genes and does not have to be learned. Examples (See chapter 52, pp. 926-927): web construction in spiders nut-burying behavior in squirrels courtship behavior in mallard ducks

Innate Behaviors are Adaptations Innate behaviors are controlled by genes. Like most genetic characters, they can vary from individual to individual. Those individuals with the most successful behaviors will leave the most offspring. Thus, those behaviors will become more common in later generations. This is adaptation by natural selection. It is not “learning” to deal with the environment.

An example: Optimal Foraging pp. 949-950 Prediction: Animals adjust their food choices so as to maximize their net resource gain. Resources include energy, vitamins, etc. “Net” resource gain means that the resources you get must be balanced against the time, energy, and risk expended to get them.

Foraging strategies Sometimes it’s best to be a generalist – eat everything you encounter. Sometimes it’s best to be a specialist – eat only the highest-quality prey and pass up the low-quality ones. Note: “Strategy” is jargon for complex patterns of behavior. It does not imply that the animals sit around formulating the plans in their minds, like generals planning a battle.

Some predictions of optimal foraging theory Specialism is better when total prey density is high; generalism is better when prey are scarce. Specialism is better when high-quality prey are abundant; generalism is better when low-quality prey are abundant. These hypotheses can be tested experimentally: Bluegill (fish) example on p. 949.

Social Behavior pp. 953-959 Actions of individuals towards others of their own species. 4 categories: Selfish Cooperative Spiteful Altruistic

Evolution of Social Behaviors It’s easy to explain selfish and cooperative behaviors. In both cases, the “performer” benefits, so it would leave more descendents, and the genes for that behavior would become more common by natural selection. The same argument predicts that spiteful behavior would be rare, and this is true.

The puzzle of altruism Natural selection predicts that altruistic behavior would be rare, because the performer is harmed; however, it’s relatively common. The best explanation for this is “Kin Selection” The performer of the altruistic behavior is harmed. But the recipient of the behavior, who is helped, is related (kin) to the performer. Thus, transmission of the gene for altruistic behavior to future generations is enhanced.

Examples of Kin Selection The simplest case is parental care of young. The parents sacrifice, but their actions ensure the success of their offspring. Thus, the genes for this behavior become more common. The same argument can be made for altruism toward nieces, nephews, siblings, cousins, etc. Since they are likely to carry the same genes, the behavior will become more common, even if the performer is harmed.

Kin selection is strongest in animals that live in family groups One example: young male wolves share their kill with their siblings. The most extreme case: sterile workers (ants, bees, etc.) who have no reproductive success at all, but work for the good of the nest. However, all the individuals in the nest are closely related, so their behavior perpetuates the genes through their siblings.

Learned Behavior Although much animal behavior is innate, some can be learned within the animal’s lifetime. Even invertebrates can learn, but this is usually simple conditioning like associating a particular taste with nutritious food. Complex learning is seen mostly in mammals, and reaches its greatest height in primates, especially humans.

Human Behavioral Ecology In humans, learned behavior becomes much more important than innate behavior. Thus, while natural selection still applies, the transmission of cultural information has as much importance as the transmission of genetic information. This is usually studied by psychologists and sociologists.