6. Mating Behavior

Question 1

Female Mating System

Answer 1

Can fertilize most or all of her eggs at once

Reproductive success is tied to availability of resources

Concerned with: parental effort & resources

Question 2

Male Mating Systems

Answer 2

Can fertilize many females

Reproductive success is tied to access to females

Concerned with: Distribution of females & need for parental care

Question 3

Types of Mating Systems

Answer 3

Monogamy, Polygyny, Polyandry, & Polygynandry

Question 4

When is monogamy adaptive?

Answer 4

Male inability to monopolize more than one female and/or there is a necessity of bi-parental care

Question 5

Monogamy in mammals is…

Answer 5

…rare.

Question 6

Monogamy occurs most often in mammals when…

Answer 6

…females live well apart from one another in small territories.

Question 7

Bi-Parental care occurs when…

Answer 7

…resources are scarce, male’s fitness may be highest when he’s part of a monogamous pair and provides some sort of care for the offspring.

Question 8

Hypotheses for Male Monogamy

Answer 8

1. Female enforced monogamy
2. Male assistance hypothesis
3. Mate guarding

Question 9

Female-Enforced Monogamy

Answer 9

Females attack promiscuous males and nearby females

Question 10

Mate Assistance Monogamy

Answer 10

In birds, males can incubate (brood) & feed nestlings which can make significant differences in offspring survival.

In mammals, only females can gestate & lactate to feed young which makes effects of male care restricted.

This may explains why Monogamy is so much more common in birds (90%) than mammals (3%).

Question 11

Monogamy & Mate Guarding

Answer 11

Benefit is it guarantees paternity, keeps females busy, and can lures new suitors away

Cost: lose opportunity to breed with other females

Question 12

Dual Mate-Enforced Monogamy

Answer 12

Males aggressive towards males & females aggressive towards females.

Question 13

Social Monogamy

Answer 13

When a male and a female have a long term sequential living arrangement. There are occasionally EPCs (extra-pair copulations) when one mate is off doing something.

Question 14

Genetic Monogamy

Answer 14

When a male and a female exclusively reproduce with one another.

Question 15

Costs of EPCs: Males

Answer 15

Time/energy searching for another female

While he’s away primary male may mate with another female

Sexually transmitted diseases

Question 16

Benefits of EPCs: Females

Answer 16

Fertility insurance hypothesis

Good genes hypothesis

Genetic compatibility hypothesis - maximize genetic diversity in their offspring

Material benefits hypothesis

Question 17

Polygyny Male Costs

Answer 17

Increased chance of cuckoldry

Costs of achieving dominance or defending a territory

Question 18

Polygyny Female Costs

Answer 18

Males don’t help with young

Females must share resources

Question 19

Types of Polgyny

Answer 19

1. Resource defense

2. Female defense

Question 20

Polygyny

Answer 20

Males have several mates

Question 21

Polyandry

Answer 21

Females have several mates

Question 22

Resource Defense Polygyny

Answer 22

Males control resources that females need (food/shelter)

Female home ranges are larger than male home ranges

Female ranges overlap but male ranges do not without fierce competition

Question 23

Female Defense Polygyny

Answer 23

Males compete for sexual access to a group of females (harems) and defend females from mating attempts with other males

Question 24

Hypothesis for Female Acceptance of Polygyny

Answer 24

1. Polygyny Threshold Hypothesis
2. “Sexy Son” Hypothesis - Access to good genes for her offspring compensated for the costs of polygyny
3. Best Alternative Hypothesis - Best of available options

Question 25

Polygyny Threshold Hypothesis

Answer 25

Females must choose between male territories, often choosing between being the only, or one of few females in a poor territory or a second female on a rich territory

Question 26

Jacanas: Resource Defense Polyandry

Answer 26

Females defend breeding territories on floating mats of vegetation which have several males per territory.

Exclusive male care of eggs.

Question 27

Polygynandry

Answer 27

Mating if multiple males with multiple females within a societal structure.

Question 28

How is polygynandry different from promiscuity?

Answer 28

Promiscuity is mating of multiple males with multiple females outside of a society structure.

Question 29

Promiscuity develops when…

Answer 29

…there is little benefit of social living, Defense of mate/resource, when lekking is costly.

Question 30

Lekking

Answer 30

When males amass into a group to entice females & allow females, who are surveying prospective partners for copulation, to peruse them.

Leks typically contain no resources.

Question 31

Hotspot Hypothesis

Answer 31

Males form leks because females frequently gather at a given location.

Question 32

Hotshot Hypothesis

Answer 32

Males form leks because subordinate males congregate around highly attractive males to increase their chance of being noticed by receptive females.

Less successful males may benefit

Females are comparison shopping

Question 33

Multiple Mating Systems

Answer 33

Some species exhibit monogamy, polygyny, polyandry, polygynandry.

Question 34

Sperm Competition

Answer 34

After a female has mates with several males, different sperm sizes and shapes.

Question 35

Kamimaze Sperm Hypothesis

Answer 35

Natural selection might favor the production of some sperm types that are designed to kill other males’ sperm rather than fertilize eggs

Question 36

Cryptic Choice

Answer 36

Female chooses which sperm is successful, length of mating, etc.