Chapter 13: Mating Systems

Question 1

monogamy

Answer 1

1 male 1 female

Question 2

polygyny

Answer 2

1 male, multiple females

Question 3

polyandry

Answer 3

1 female, multiple males

Question 4

polygyandry

Answer 4

plural breeding, multiple males and females with some social associations

Question 5

promiscuity

Answer 5

multiple males and females, no social associations

Question 6

sexual conflict

Answer 6

differential selection on males and females to maximize their fitness
female fitness is limited by access to resources to invest in offspring
male fitness is limited by access to mates/females

Question 7

Emlen and Oring Model

Answer 7

describes when to expect the different mating systems
uniform to clumped, female to male biased care.

monogamy- if female’s partner offers high resources and parental care. uniform or clumped and mid bias. favoured if resources are poor and predation is high.

polyandry- clumped, male biased care

polygyny- resource/female defence if clumped, male dominance if uniform.
females aggregate to lower predation risk and male harassment while having resource access.

Question 8

why might females gather

Answer 8

avoid predation
avoid male harassment
get resource access

Question 9

resource defence polygyny

Answer 9

male defend a territory that attracts females

Question 10

female defence polygyny

Answer 10

male monopolize resources and defend females due to resources

Question 11

male dominance polygyny

Answer 11

(leks)
males advertise to females in a group

Question 12

promiscuity

Answer 12

not really on graph. can be male or female biased care, cant predict. theres low benefit to social living so they dont stick together.

Question 13

warbler E+O model approach/methods

Answer 13

comparative analysis, examine related species’ mating systems.

Question 14

warbler E+O research question

Answer 14

how does habitat quality correlate with mating system?
how are habitat quality and mating systems related to level of male care?

Question 15

warbler E+O model methods

Answer 15

create phylogeny
estimate habitat quality
characterize relative male care for offspring

Question 16

warbler E+O results

Answer 16

poor habitat: monogamy, high parental care
medium or good habitats: polygyny, promiscuity and reduced male care

Question 17

cali mouse observation

Answer 17

cali mice are monogamous (rare for mammals)

Question 18

cali mouse research question

Answer 18

how does male care affect reproductive success in this species?

Question 19

cali mouse prediction

Answer 19

reproductive success will be low if paternal care is absent

Question 20

cali mouse methods

Answer 20

capture adults
check females for reproductive condition
remove males from monogamous pair within 3 days of litter birth
estimate # young born by comparing mother weight loss between last days of pregnancy and first capture since birth
compare offspring number and success (emergence from burrow) to control pairs with males

Question 21

cali mouse results

Answer 21

both groups had similar # young
litters with no father had much lower success

Question 22

cali mouse conclusion

Answer 22

male care enhances reproductive success in monogamous mice

Question 23

shrimp monogamy research question

Answer 23

why are shrimp monogamous when the males provide no care?

Question 24

territorial cooperation hypothesis

Answer 24

2 individuals (one of each sex) can better defend a critical resource

Question 25

mate guarding hypothesis

Answer 25

a single male can benefit from remaining close to single female during reproductive cycles

Question 26

shrimp monogamy predictions

Answer 26

pairs will better defend resource males will most often guard females close to sexual receptivity

Question 27

shrimp monogamy methods

Answer 27

allowed single females and paired females to guard burrow from intruder (same size/sex) allowed males to choice females close to or not close to sexual receptivity

Question 28

shrimp monogamy results

Answer 28

females paired with male were more successful in burrow defence males chose to guard sexually receptive females more often

Question 29

shrimp mate research question

Answer 29

how are males able to determine female sexual receptivity

Question 30

shrimp mate methods

Answer 30

Y tank 1 arm normal water 1 arm treated (had shrimp, then had pre/post/inter molt females)

Question 31

shrimp mate results

Answer 31

males only moved to water with pre molt female

Question 32

shrimp mate conclusion

Answer 32

males were able to determine female sexual receptivity and are attracted to them territorial competition and mate guarding have favoured monogamy in shrimp

Question 33

horse observation

Answer 33

feral horses live in bands with 1 male and up to 12 females

Question 34

horse research question

Answer 34

do males defend females directly or the resources the females want?

Question 35

horse methods

Answer 35

record location of bands for 3 years record social behaviours especially aggression between males of different bands plot home range of each band

Question 36

horse results

Answer 36

bands overlapped so much, there was no defence of territories, the males fought over female access.

Question 37

horse conclusion

Answer 37

males seem to display female defence polygyny

Question 38

blackbird observation

Answer 38

blackbirds exhibit variation in their mating system

Question 39

blackbird research question

Answer 39

why do some blackbirds mate monogamously, others polygynously?

Question 40

blackbird hypothesis

Answer 40

polygyny threshold model. there will be variation in polygyny dependent on territory quality (or direct benefits)

Question 41

blackbird prediction

Answer 41

polygyny should only be observed in high quality territories

Question 42

how do female blackbirds nest?

Answer 42

they nest in dense vegetation around ponds. they mate monogamously or polygynously

Question 43

blackbirds methods

Answer 43

females could mate monogamously in low quality territory or polygynously in high quality territory. Add nesting platforms over water (high quality territory) for polygynous male nesting platforms over land (low quality) for monogamous male

Question 44

blackbird results

Answer 44

majority chose to mate polygynously on high quality territory.

Question 45

blackbird conclusion

Answer 45

territory quality affects observed mating system, as predicted by polygyny threshold model

Question 46

carrion beetle observation

Answer 46

males defend small vertebrate carcasses and females larvae feed on it. observe male-male aggression but not female-female over carcass.

Question 47

carrion beetle research question

Answer 47

does the variation in aggression between sexes indicate that these beetles exhibit resource defence polygyny?

Question 48

carrion beetle methods

Answer 48

place 2 males and 2 females next to meat within each sex there was variation in size. large males dominant over small females mated with both males record mating success via DNA analysis

Question 49

carrion beetle results

Answer 49

large males had much more reproductive success females had similar success with a slight edge to larger one

Question 50

carrion beetle conclusion

Answer 50

resource defence polygyny is the mating system, males defend carcasses to keep smaller males away

Question 51

lek

Answer 51

communal display ground where males showcase their secondary sex characteristics to impress females. there is usually a male dominance hierarchy on these leks

Question 52

2 hypothesis to explain aggregation on leks?

Answer 52

hotspot hypothesis: males benefit by aggregating on leks where female encounter is more likely hotshot hypothesis: males benefit by aggregating on leks were high quality males are, that attract females

Question 53

great snipe observation

Answer 53

males display on leks for several hours each evening