Mating Systems

Question 1

What is a mating system?

Answer 1

How many mates are acquired, and the type of pair bond.

Question 2

Promiscuity

Answer 2

A mating system with no stable relationship, where mating between two individuals only happens once.

Question 3

When do we see more polygyny?

Answer 3

Highly clumped resources, highly clumped potential mates.

Question 4

When do we see more monogamy?

Answer 4

Widely-distributed resources, widely distributed potential mates.

Question 5

EPP

Answer 5

Environmental Potential for Polygamy

Question 6

Species Biology and Mating Systems

Answer 6

Factors that can influence the mating system:
- Size of territory that a male is capable of defending.
- Female receptivity duration.

Question 7

Social mating system vs. Genetic mating system

Answer 7

Based on observed interactions between individuals (can be inaccurate) vs. based on maternity and paternity (DNA)

Question 8

Monogamy

Answer 8

One male forms a pair bond with one female.
Multipurpose territory or nest site only defended by male or both sexes.

Question 9

Why does male monogamy exist?

Answer 9

• Mate assistance (net benefit from assisting)
• Mate guarding (high payoff)
• Female enforcement (chasing off other females, attacking males who mate with other females)

Question 10

Monogamy in dikdiks

Answer 10

Both sexes scent marking. Males can hide female’s reproductive state from other males in this way. Haven’t found extra-pair copulations.

Question 11

Polygyny (and the three kinds of it)

Answer 11

One male forms a pair bond with several females simultaneously.

3 kinds:
- Resource Defense Polygyny
- Female Defense Polygyny
- Lek Polygyny

Question 12

Resource Defense Polygyny

Answer 12

Males control females indirectly by monopolizing critical resources that she needs (to eat, lay eggs, etc.)

Question 13

Female Defense Polygyny

Answer 13

Males control females directly.
Males may defend groups of females permanently or seasonally.

Question 14

Lek Polygyny

Answer 14

Males aggregate at traditional sites (leks) and display communally. Nothing but sperm is provided to the females. Females select a mate, and the aggregation of males at one location greatly facilitates comparison of males by females, and the accurate selection of the best one.

Question 15

Why do males aggregate on leks?

Answer 15

Hotspot hypothesis: males congregate where female encounter rate is high
Hotshot hypothesis: subordinate males cluster around highly attractive males hoping to get access to females attracted to ‘hotshots’
Female preference hypothesis: females prefer large groups of males because they can quickly compare them. Aggregated males get visited more often by receptive females.

Question 16

Consequences of Leks

Answer 16

• Opportunity for female mate choice and male-male competition is unusually high.
• Males are highly ornamented.
• Females visit several males before copulating, and are highly selective.

Question 17

Paradox of the Lek

Answer 17

Matings are strongly skewed to just a few males.
With this strong skew, a few generations of female choice should deplete most genetic variation in quality.

Question 18

When does polygyny benefit females?

Answer 18

Polygyny could be chosen by females if polygynous territory quality is sufficiently high. Common in patchy environments for this reason.

Question 19

Polyandry

Answer 19

One female forms a pair bond with several males simultaneously.
- Several males defend one female’s territory.
- Female defends large multipurpose territory within which several males defend smaller, exclusive territories.

Question 20

Polyandry and Jacanas

Answer 20

Sex roles reversed; males are smaller, look after chicks, and females usually have multiple mates.