Mating systems

Question 1

Mating system classification, what this encompasses?

Answer 1

• Copulation behaviour
• Social organisation
• Parental care system
• Competition for mates

Question 2

What is monogamy?

Answer 2

• 1 male and 1 female
• Can be long or short term bonds
• Often both sexes care for young
• Most birds, few mammals and fish

Question 3

What is polygyny?

Answer 3

• Males associate with many females
• Females associate with single male
• Few birds and most mammals

Question 4

What is Polyandry

Answer 4

• One female associates with many males
• Few birds, fish and mammals
• Fairly rare

Question 5

What is Promiscuity (polygynandry)?

Answer 5

• Both sexes have several mates
• Either or neither sex care for the young
• Few birds, few mammals, many fish, reptiles and amphibians

Question 6

What are the fundamental differences between male and females ?

Answer 6

• Gamete size
• Males have a higher reproductive potential than females

Question 7

Evolution of mating systems (What is the general model?)

Answer 7

Ecology effects female dispersion which then in turn effects male dispersion.

Question 8

What does female monopolisation by males and the mating systems depend on?

Clutton-brock

Answer 8

1. Female group size
2. Female range size

Question 9

When solitary females are dispersed what male competition occurs?

Answer 9

Scramble Competition

Question 10

What is scramble competition?

Answer 10

• When females cover a wide range (due to food searching)
• The range the female covers is not defensable by male
• Male search for fertile females and guard them until pregnant
• Leave to find other fertile females once pregnant

Question 11

When females are social and occupy small ranges that are defendable by males what mating systems occur?

Answer 11

• Uni-male polygyny (small groups) e.g. colobus monkeys
• Multi-male polygyny (large groups) e.g. lions

Question 12

What mating systems occur when large groups of females occupy large ranges?

Answer 12

• Lekking
• Lek polygyny
• Often results in extreme sexual competition and sexual dimorphism

Question 13

What animal was used to show how ecology effects female dispersal

Answer 13

Grey-sided vole

Question 14

Grey-sided vole: Does food distribution determine female dispersion?

Experiment 1

Answer 14

• Yes but males also converged food
• Was the male range size shrinking because of females or because the food source was shrinking?

Question 15

Grey-sided vole: Does females range size effect male dispersion?

Experiment 2

Answer 15

• Captive females, radio-tracked males
• When females were clumped together, the males range size shrunk
• When females were spread over the larger area the males range size increased.
• Female dispersion determines male dispersion within an environment

Question 16

Grey-sided vole: Does male dispersion effect female range size?

Experiment 3

Answer 16

• Reverse expt: captive males, radio-tracked females
• No effect of male dispersion on female dispersion

Question 17

What is resource defence polygyny?

Answer 17

Males defend resources that females want

Question 18

Example of resource defence polygyny?

Answer 18

• Tent-making bats
• Males construct and defend roosting tents which house harems of females
• High female to single male ratio

Question 19

What happens in mating systems with paternal care?

Answer 19

• Males are critical to females
• Male dispersal determines female dispersal

Question 20

How can parental care determine mating systems?

Answer 20

Parental care, particularly paternal care, is pivitol in determining the emerging mating system that occurs

Question 21

Sexual conflict over mating systems

Answer 21

• Males prefer polygyny
• Females may prefer polyandry if they get more/better resources (e.g. paternal care)
• In many species monogamy occurs as a compromise between conflicting interests of the sexes