mating behavior - chapter 12

sexual selection

A form of natural selection that acts on heritable traits that affect reproduction

nonrandom mate choice

intrasexual selection (mate competition) and intersexual selection (mate choice) go under this category

primary sexual characteristics

the genitalia and organs of reproduction

secondary sexual characteristics

morphological differences between the sexes that are not directly involved in reproduction

intrasexual selection

a situation in which members of the same sex compete for access to the other sex for reproduction

intersexual selection

selection by one sex for members of the other sex for reproduction

isogamy

the production of gametes of the same size by all individuals

anisogamy

the existence of differently sized gametes (small and large) in the different sexes

Bateman’s hypothesis

the hypothesis that female reproductive success is most strongly limited by the number and success of eggs that she can produce, while male reproductive success is limited by the number of mates he has

parental investment

any investment by a parent that comes at a cost of that parent’s ability to invest in other offspring

parental investment theory

hypothesis that the sex that pays the higher cost of parental investment should be choosier when it comes to mates

weapons

exaggerated morphological traits used in competition with individuals of the same sex

ornaments

exaggerated morpho­logical traits used to attract mates

sex-role reversed species

a species in which females compete for males that invest heavily in parental care

sensory bias hypothesis

hypothesis that female mating preferences are a byproduct of preexisting biases in a female’s sensory system

direct material benefits

material resources obtained by a female from mating with a particular male

nuptial gift

a physical resource such as a food item that an individual provides to a potential mate to enhance mating success

territory quality

affects female choice and fitness; direct fitness benefit for females that select high-quality ___

indirect genetic benefits

genetic benefits females can obtain for their offspring by mating with males that have high genetic quality

Fisherian runaway selection

females select mates based on a particular trait that varies among males. Such a trait could evolve because of

• (1) its fitness advantage, independent of female choice

• (2) female preference for it

• male trait should co-evolve with the female preference and become increasingly exaggerated

an evolutionary process in which a male trait co­evolves with a female preference for it and becomes increasingly exaggerated

linkage disequilibrium

occurs when the genotype at one locus is not independent of the genotype at another locus

handicap principle

hypothesis that well­-developed secondary sexual characteristics are costly because they handicap survival

good gene hypothesis

the alleles of a high­ quality individual; hypothesis predicts that females should base their mating decisions on costly male traits to obtain indirect genetic benefits; a genetic correlation is assumed between the female preference for the male trait and the male “good genes” that provide enhanced physical vigor and are indicated by the trait

Hamilton-Zuk hypothesis

hypothesis that parasites and pathogens play an important role in sexual selection when secondary sexual traits are costly and condition dependent

mate guarding

a behavior in which a male remains close to his mate to prevent her from mating with rivals

sperm competition

a situation that occurs when the sperm of different males compete to fertilize eggs

cryptic female choice

a situation that occurs when a female influences the fertilization success of sperm from one male over that from others

alternative mating tactics

the existence of multiple behavioral mating phenotypes in a population

bourgeois strategy

competitive males defend a territory to monopolize its resources for females or else possess traits attractive to females

• typically, males are large, older, and in the best physiological condition

parasitic strategy

used by less competitive males to usurp matings from bourgeois males

• examples of behaviors: satellite male & sneaker male

satellite male

associate with bourgeois males by remaining near them to intercept females that are attracted to the bourgeois individual

sneaker male

do not defend territories but instead intrude while a parental male is spawning with a female in an attempt to fertilize eggs as they are laid; avoid detection, quickly enter bourgeois territory to fertilize eggs deposited in nest

mate choice copying

a situation in which one individual observes and copies the mating decisions of another individual