Animal Behavior Chapter 10 - Mating Systems

Polyandry

Females have multiple partners but males only have one.

Polygyny

Males have multiple partners and females have only one.

Polygynandry

Both sexes have multiple mates but they do have bonds with a specific one/

Promiscuity

Both sexes have multiple mates but their are no bonds

Monogamy

Both sexes only have one mate.

Mating systems can be _________ based on situation.

plastic

What is the mating system influenced by?

Resources and ability to monopolize them.

When there is a greater potential to monopolize mates/ resources leads to greater chance mating system has….

1 sex mating several times.

When does monogamy occur?

Neither sex can monopolize access to mates or resources and the cost of mating multiple is too high.

What are the characteristics of monogamy?

Very rare and their is social vs genetic.

What are the costs of monogamy?

Time and energy lost, predation risk looking for new mates. Fitness cost from sexually transmitted disease if multiple partners.

Mate limitation hypothesis

Potential mates are not in groups and roam freely making it costly to find them.

Mate guarding hypothesis

Individuals have the ability to restrict mating behavior in their partner. Forced monogamy.

Mate Assistance Hypothesis

Resources are so critical to successful reproduction that both parents are necessary to rear young.

Males with experimentally lower testosterone levels provided ______ than those with control or high testosterone lebels.

more care

Monogamy is _____ in mammals (due to internal gestation and lactation) but if males provide some paternal care, expect more monogamy.

rare

Infanticide Hypothesis

If infanticide risk if higher and partner can provide protection against infanticidal males.

Direct and Indirect Benefits of Choosy Females

Good gene hypothesis, parental care, access to resources, safety from predators, and reduced harassment from other males.

Why do some males NOT have their own extra-pair copulations?

If wont/cant give good paternal care OR cant show good genes to gain extra.

Where is social monogamy and genetic polyandry common?

Social monogamy is favored in males and genetic polyandry by females in birds and other species.

Sex-Revered Species

Females possess spikes used to fight other females to secure territories. Males fertilize eggs and raise them themselves.

Good Genes Hypothesis (Sexy sons) (INdirect)

Offspring have higher genetic quality or viability

Genetic Compatibility Hypothesis(Indirect)

Increases odds of receiving genetically complementary sperm.

Genetic Diversity Hypothesis(Indirect)

Increases the heterozygosity of either individual offspring or of the group of offspring produced in a single bout.

Inbreeding Avoidance Hypothesis(Indirect)

Avoidance of inbreeding with their social partner.

Additional Resources Hypothesis (Direct)

Gain access to additional resources from their partner

Additional Care Hypothesis (Direct)

Gain more caregivers to help rear young.

Female Defense Polygny

When resources are evenly distributed in space and female form groups to better access those resources or to help dilute the predation risk, males will follow and guard a group of females.

Resource Defense Polygyny Hypothesis

When resources are clumped, attract females and are easily defensible, males will guard the resources AND females by setting up a territory.

Lek Polygyny Hypothesis

When resources are distributed heterogeneously and females are widespread and do not form groups, males will wait for females to come to them.

Hotspot Hypothesis:

Males cluster in places (called “hotspots”) where the routes frequently traveled by receptive females intersect

Hotshot hypothesis:

Subordinate males cluster around the highly attractive males to have a chance to interact with females drawn to these “hotshots”

Female Preference Hypothesis:

Males cluster because females prefer sites with large groups of males, where they can quickly or safely compare the quality of many potential mates.

Is there any single hypothesis that explains lekking for all species?

No