mating systems - chapter 13

mating systems

a description of the social associations and number of sexual partners an individual has during one breeding season

monogamy

a mating system in which one female mates with one male

polygyny

a mating system in which a single male associates and mates with multiple females

polyandry

a mating system in which a single female associates and mates with multiple males

polygynandry (plural breeding)

a mating system of social species in which multiple males and multiple females associate with one another and produce young in one breeding attempt

promiscuity

a mating system in which both males and females mate with multiple partners in the absence of pair bonds

sexual conflict

the differential selection on males and females to maximize their fitness

Emlen and Oring’s model

model which argued that mating systems can be understood by examining two factors:

• one is evolutionary: sexual conflict, or the differential selection on males and females to maximize their fitness

• the other factor is ecological: the ways in which resource limitation and distribution affect fitness benefits and costs for each sex

female aggregations

environmental conditions can lead to this; these are more easily defended by a male from rivals

two factors can promote this:

• females may experience lower predation risk than solitary females, or a group of females may more successfully avoid harassment from males

• the distribution of resources in the environment. If the resources required by females are clumped, males can monopolize females by defending territories with large amounts of such resources

female defense polygyny

a mating system in which a single male monopolizes and mates with two or more females

clumped resources

if the resources required by females are _____, males can monopolize females by defending territories with large amounts of such resources

resource defense polygyny

a mating system in which a male mates with multiple females that are attracted to resources he defends

lek

a location where males aggregate and display to females

dominance hierarchies

an organized social system with dominant and subordinate members.

male dominance polygyny

a mating system in which a few males on a lek mate with many females

biparental care

both parents provide care for offspring

territorial cooperation hypothesis

the hypothesis that two individuals (one of each sex) can better defend a critical resource, such as a safe refuge, than can a single individual, and thus selection may favor pair formation and shared defense

mate guarding hypothesis

the hypothesis that selection favors males that mate with and guard one female over one or more reproductive cycles by remaining in close association with her

polygyny threshold model

a model that predicts the occurrence of polygyny based on the amount of resources available to females in male territories

hotspot hypothesis

all males can benefit by aggregating in a location where they are likely to encounter many females

hotshot hypothesis

a proposed explanation for the evolution of leks. It states that males can increase their encounter rate with females by aggregating near an attractive male

extra-pair copulation (EPC)

the copulations of a pair-bonded individual with a third individual outside the pair bond

social mating system

the social associations and presumed mating behavior of individuals based on those associations

genetic mating system

a description of the mating system based on the actual number of sexual partners in a social mating system that contribute to a set of offspring

genetic quality hypothesis

the hypothesis that females that engage in multi-male matings can improve the fitness of their offspring via genetic mechanisms

heterozygosity

A female can benefit by mating with an extra-pair mate that is genetically more dissimilar to herself than her social mate, because this will increase the level of ___ of her offspring

• the state of possessing two different versions, or alleles, of a particular gene

• high degree of genetic diversity within a population or individual, indicating a variety of different allele combinations at a given genetic locus

• signifies that many individuals within a population carry different versions of the same genes, leading to more diverse traits and potentially increased adaptability