8. Mating Systems

Question 1

What is monogamy?

Answer 1

One male and one female in a mating pair

Question 2

What is polygyny?

Answer 2

One male mating with multiple females

Question 3

What is polyandry?

Answer 3

One female mating with multiple males

Question 4

What is promiscuity?

Answer 4

Both males and females having multiple partners

Question 5

What is polygamy?

Answer 5

Polyandry, Polygyny, and Promiscuity

Question 6

What are the three types of mating systems?

Answer 6

No male care
Lekking and variations
With male care

Question 7

In systems with no male care, what determines the males reproductive tactics?

Answer 7

Female distribution in space and time.
Even = low potential for polygamy
Patchy = high potential for polygamy

Question 8

What is OSR?

Answer 8

Operational Sex Ratio

Ratio of receptive females to sexually active males

Question 9

What are the two types on breeders found with temporal dispersion of females?

Answer 9

Prolonged breeders (Bullfrogs - 0-6 mates/male)
Explosive breeders (Common toad - 1-2 matings/male)

Question 10

What are the characteristics of a mammalian mating system when the females are solitary with defensible range?

Answer 10

If female range is small - Polygamy
If range is large - Monogamy
Males may help with offspring care or predator defense
Parental care - larger litter size

Question 11

What are the characteristics of a mammalian mating system when the females are solitary with a non-defensible range?

Answer 11

Females and males only associate during oestrus

E.g. Orang-utan - Females move with resources (fruit)

Question 12

When would scramble competition polygyny occur?

Answer 12

Females are solitary and the range is not defensible

e.g. ground squirrels, males constantly monitor females to find one in oestrus

Question 13

What happens when females are social and the range is defensible?

Answer 13

Harems for many primates
Large range - several males defend territory
Males compete over females (sometimes leads to infanticide)

Question 14

What happens when females are social and the range is not defensible?

Answer 14

Female dispersal in space and time.
If daily movements are predictable - defense of mating territories
If daily movements are not defensible - sometimes harem defence (seasonal or permanent)

Question 15

What is lekking?

Answer 15

When males group together and advertise qualities.
Females only visit leks to mate
Mating success is normally very skewed within the lek

Question 16

When does lekking normally occur?

Answer 16

When neither females nor resources are defensible

Question 17

What are the 5 reasons as to why lekking may occur?

Answer 17

Hotspots hypothesis
Hotshot males
To increase female attraction
To facilitate mate choice
Reduce predation

Question 18

What is the hotspot hypothesis?

Answer 18

Males cluster in areas that females frequent

Question 19

What is the hotshot hypothesis?

Answer 19

Males cluster around high quality males

Question 20

Why lek to attract females?

Answer 20

Stimulus pooling - Several males create a more powerful signal than one

Question 21

Why lek to facilitate female choice?

Answer 21

Females prefer aggregations - provides a ‘testing ground’

Question 22

Why lek to reduce predation?

Answer 22

Calling males are safer - dilution effect etc

Question 23

When do males become a resource to females?

Answer 23

When they start providing parental care

Question 24

What is obligate monogamy?

Answer 24

Both parents necessary to raise offspring
Increase in fitness if stay with same mating partner and share raising brood
Seeking a new mate can be costly - time taken to synchronise (White’s seahorse)

Question 25

What are some of the benefits of polyandry? (similar to mate choice benefits in general)

Answer 25

Direct - resources, offspring care, reduction in infanticide

Indirect - good genes, inbreeding avoidance, diversity among offspring, disease resistance

Question 26

How is monogamy often enforced?

Answer 26

By partner’s behaviour - anti-aphrodisiacs, damage to female, mate guarding, mating plugs
Costs of polygyny - time, energy, search costs, STI
Lack of available mates OSR

Question 27

When do many polygamy conflicts occur?

Answer 27

When the males and females have different optimum mating behaviours

Question 28

Which species have a sex role reversal

Answer 28

Pipefish
Red-necked phalarope
Spotted sandhopper

Question 29

What is Batemann’s logic behind sex role reversal?

Answer 29

Male RS limited by time

Female RS limited by matings

Question 30

Are males stuck to one mating tactic?

Answer 30

No they are able to switch between, once the male becomes large enough he will switch to aggressive tactic

Question 31

When will only the largest males be successful?

Answer 31

When male-male competition is intense

Question 32

What is a protogynous sex change?

Answer 32

Starting life as a female and switching to male when largest

Question 33

What is a protoandrous sex change?

Answer 33

Starting life as a male and changing sex when largest