Behavioral Ecology

Behaviors

actions in response to a stimuli

quorum sensing

The ability of bacteria to sense the presence of other bacteria via secreted chemical signals

What encodes behaviors?

genes

proximate cause

how action occurs

ultimate cause

why action cause

What are behaviors subject to?

selection

sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Inclusive fitness

The total effect an individual has on proliferating its genes by producing its own offspring and by providing aid that enables other close relatives to increase the production of their offspring.

Inclusive fitness equation

(individual fitness) + relatedness x fitness of relative

If a male cannot reproduce but his brother produces 6 offspring, what is his fitness?

3; 0 + .5 x 6

How related are you to your father, mother, offspring, and sibling?

50%

how related are you to were half-sibling and niece/nephew?

25%

How related are you to your cousin?

12.5%

What is Hamilton's Rule?

rB>C

r - fraction of shared genes between altruist and recipient (coefficient of relatedness)

B - average number extra offspring beneficiary produces (benefit)

C - how many fewer offspring altruist produces (COST)

optimal foraging model

treats foraging behavior as a compromise between the benefits of nutrition and costs of obtaining food

Costs of foraging

every expenditure and risk of being eaten

Male investment in offspring

small gametes in great numbers

Female investment in offspring

female make fewer large gametes, contribute disproportionately to nutrition of offspring

How did females and males make up for their sexual costs?

- males can enhance fitness by mating with many females

- females become selective to avoid poor selection

Species where males invest heavily in offspring

- seahorse males carry children

- mouthbrooders hold babies in mouth

Uta stansburania

fitness of a particular phenotype depends on phenotypes of other individuals in population

alturism

improving fitness of another individual at cost to one's own fitness

When is altruism evolutionarily stable?

when it leads to net increase in fitness

What kind of gametes do ants, bees, and wasps have?

haplodiploid

Altruistic behaviors can be maintained when

Relatedness combined with an increase in fitness more than balance the fitness costs to the altruist

If you ask a question about behavior that concerns how it works, or what its mechanism is, you are asking a question that involves

proximate causation