Ngoc-chapter 8 Behavioral Ecology

An animal’s behavioral decisions play a critical role in activities such as ………

obtaining food, finding mates, avoiding predators

……………affect an individual’s ability to survive and reproduce

costs and benefits from animals behavioral decisions

What is the behavioral ecology?

It is the study of the ecological and evolutionary basis of animal behavior

How can animal behaviors be explained?

By proximate causes (intermediate- how the behavior occur) and ultimate causes (why the behavior occurs- evolutionary explanation)

How do Robins’ sensory organs work by tilting their heads?

By proximate cause

Natural selection should favor individuals whose behaviors make them efficient at:

- Foraging

  - Obtaining mates

  - Avoiding predators

If the traits that confer advantage are heritable, natural selection can result in ………….

adaptive evolution

Most aspects of animal behavior are controlled by?

Both genes and environmental conditions.

Do genes affect many behaviors?

Yes

individuals with adaptive alleles may change their behavior based on………

the environment

if genes affect behaviors, and natural selection has caused behaviors to evolve over time, we can make …………….. about how animals will behave.

predictions

Animals make behavioral choices that …………………… and……………..

enhance their energy gain'………….reduce their risk of becoming prey.

What is foraging?

the process of finding, processing, and eating food

Foraging decisions are based on a food item’s:

§Size

§Energetic value

§How easy it is to carry

§Its distance from cover

§And how these variables interact

What is optimal foraging theory?

Animals will maximize the amount of energy gained per unit of feeding time, and minimize the risks involved.

What are assumes?

It is a natural selection acts on the foraging behavior of animals to maximize their energy gain.

An animal’s success in acquiring food increases with the effort it invests; but at some point, more effort results in no more benefit, and the net energy obtained begins to increase/decrease

decrease

highest/lowest net energy gain represents ideal effort investment

highest

In Caveats, The assumption that energy is in high/short supply, and that this dictates foraging behavior, may not always hold

short

What other resources are as important as energy in caveats?

Nitrogen or sodium content of food

What is the Marginal Value Theorem?

It is the Offshoot of the optimal foraging theory that applies to “patchy” landscapes

In Marginal Value Theorem, The rate of energy gain in a patch is initially low/high.(1) An animal should stay in a patch until the rate of energy gain has increased/declined (2)to match the average rate for the whole habitat (giving up time).

1. high

2. declined

What influences the giving up time in foraging behavior?

The distance between patches. Therefore, the longer the travel time between food patches, the longer an animal should spend in a patch.

When do foraging behavior change?

When the predator is present

Mating behaviors reflect the …………..of parental investment and mate defense.

costs and benefits

What do males and females differ in?

physical appearance and behavior

In sexual selection, Individuals with certain characteristics gain an advantage over others of the same sex solely…………….

with respect to mating success

In intrasexual selection, …….

individuals of the same sex compete for access to mates

In intersexual selection, ………..

preferences of the opposite sex influences choice. Females choose mates with certain preferred characteristics

What mechanism for sexual selection do “Females perceive certain traits (size, ornamentation, coloration) as indication of “better genes” represent?

Intersexual selection

Do female mating preferences affect male mating success?

yes

The sexy son hypothesis

Female benefits indirectly because sons will win the preference of other females, increasing the number of grandchildren

The handicap hypothesis

a male that can support a costly and unwieldy ornament is likely to be a vigorous individual whose overall genetic quality is high. Female benefits indirectly by passing on good genes to both sons and daughters

Why do females want the best male?

To “protect” her investment, females only want the best males (provide ample resources; best genes)

Because of these costs in female, males often produce less/more offspring during their lifetimes than females.

more

………………. can also influence mating systems: number of mating partners and patterns of parental care

Ecological factors

Polygymy

1 male mates with multiple females in a breeding season

monogamy

1 male mate with 1 female

polyandry

1 female mates with multiple males in a breeding season

promiscuity

both males and females mate with multiple partners

Benefits of group living

-Higher reproductive success

-Group members share feeding and care

-Reduced risk of predation

-Foraging success

Costs of group living

-food comperition, mates

-Parasites and diseases spread easily

-Food are comsumed rapidly

-More time may be spent in moving between feeding sites.

dilution effect

population increases→ less risk of being attacked

Group size may reflect a balance between……………

costs and benefits

Optimal group size should be the size at which ………….

net benefits to the members are maximized

Measuring behaviors is ……..

-Not straight forward, yet must be defined and given units

-We have to define behaviors in simple terms

-Context is incredibly important

The Ethogram

a set of defined behaviors exhibited by a specific animal species