Evolution of Mating Systems

Question 1

mating system

Answer 1

how mates are acquired, the type of pair bonds. Summarizes who mates with who, and how.

Question 2

monogamy

Answer 2

1 male and 1 female mate in a pair bond.

male has 1 female within his territory.

there is social and genetic monogamy

Question 3

polygyny

Answer 3

1 male, 2+ females. One male forms pair bonds with multiple females.
resource defence polygyny
female defence polygyny
lek polygyny

Question 4

polyandry

Answer 4

1 female, 2+ males. One female forms multiple pair bonds with several males.

several males may defend one female’s territory
female may defend multiple male territories.

Question 5

promiscuity

Answer 5

2+ males or females

Question 6

extra pair copulations

Answer 6

can only occur in pair bonded species. copulations that occur outside the pair

Question 7

Bateman’s Principle

Answer 7

female reproductive success is limited by access to resources, male reproductive success is limited by access to females

Question 8

what does the Bateman’s Principle say about mating system organization?

Answer 8

females disperse to where the resources are, and then males will disperse to where the females are. this dispersal pattern makes up the mating system.

ecological factors (resources) dictate the mating system. Highly clumped resources means highly clumped females/mates for the male. It is up to the male to attempt to monopolize these females. (leads to polygyny)

it is harder to monopolize widely distributed females, and this leads to more monogamy.

(depends on size of territory the male can defend and how many females live within it)

Question 9

synchronous breeding/brief receptivity

Answer 9

all females are sexually active and receptive to breeding at the same time

Question 10

asynchronous breeding/ prolonged receptivity

Answer 10

females are sexually receptive at different times.

Question 11

female receptivity duration

Answer 11

influences the temporal distribution of mates, and the mating system

Question 12

factors influencing mating systems

Answer 12

male and female dispersal patterns
cost and benefits of mate guarding/defence
(size of territory, receptivity duration)

ecology and biology of species determine mating system

Question 13

social mating system is the same as genetic mating system

Answer 13

false.

social mating is based on observed interactions between individuals, and can be inaccurate

genetic mating system is based on parentage of offspring (DNA)

Question 14

why does male monogamy exist?

Answer 14

mate assistance (males get net benefit from assisting)
mate guarding (pays to guard when few other opportunities exist)
female enforcement (females chase off other females, or attack males attempting to mate with other females. female imposed monogamy)

Question 15

maintaining monogamy in dikdiks

Answer 15

both sexes scent mark, and males will scent mark over females to hide the fact that there is a reproductive female from other males.

males will attack females that leave the territory.

Question 16

resource defence polygyny

Answer 16

males control females indirectly by monopolizing critical resources that females need. Males can become polygynous if they hold onto the resources, or they need to care for young.

usually many female territories in one larger male territory.

Question 17

female defence polygyny

Answer 17

males directly control females. When females are social, their movements are predictable, and males may defend groups of females seasonally or permanently.
many females live within a male’s territory

Question 18

lek polygyny

Answer 18

no paternal care
males aggregate at traditional sites (leks) to display
lek sites provide no essential resources to female other than male sperm
females select a mate from the displaying males. The aggregation of males allows for comparison and accurate selection of the best one

Question 19

why do males aggregate on leks?

Answer 19

hotspot hypothesis: males aggregate on “hotspots”, where female encounter rate is high

hotshot hypothesis: subordinate males cluster around attractive males hoping to interact with the females attracted to hotshots

female preference hypothesis: females prefer large groups of males where they can easily and quickly compare them. Aggregated males are visited more often by receptive females.

Question 20

consequences of leks

Answer 20

female mate choice and male-male competition is unusually high
lekking males tend to be highly ornamented and perform striking and conspicuous displays (predation)

Question 21

The paradox of the lek, and a proposed solution

Answer 21

Paradox: with high variance in male reproductive success, within a few generations of selection via female choice, the genetic variation in quality should be depleted, and yet theyre not.
Solution: condition-dependent traits. If a male is to display the most elaborately, he must be able to survive and thrive in harsh conditions. Not all males will handle the stress the same way, and the gene-environment interactions along with stress on development may reduce the size of the trait.

Question 22

does polygyny benefit females?

Answer 22

females prefer polygyny if the territory is good enough

Question 23

female mating system choice experiment result

Answer 23

when faced with monogamy and a low quality territory, and polygyny on a high quality territory, females chose the polygyny

Question 24

Jacanas mating system

Answer 24

sex role reversed, males are smaller and look after chicks. females are polyandrous and have 1-4 mates.

resource distribution affects male distribution.