Mate Choice

Question 1

mate choice is also called

Answer 1

intersexual selection

Question 2

which sex typically is choosier, and why?

Answer 2

females
they have more to lose in reproduction (they invest more) so female choice is more of a selective force

Question 3

what do females choose for?

Answer 3

direct benefits (nuptial gifts, paternal care, good territories, good resources.)

indirect benefits (genetic quality)

Question 4

what do females gain when they choose for male resources?

Answer 4

males use food to convince females to mate.
Nuptial gifts
females prefer bigger nuptial gifts, and will mate longer the larger the nuptial gift is

Question 5

what do females gain when they choose for resources held by males?

Answer 5

a good territory with minimal predation or plenty of food

Question 6

what do females gain when they choose for parental ability?

Answer 6

males who can take care of young.
may dump eggs for male to care for, must be able to defend nest
may need help getting food for chicks. If father brings more food, more young can develop.

Question 7

what do female sand gobies look for when choosing a male?

Answer 7

they prefer to lay eggs in a nest that already has eggs in it.

Question 8

widow birds study

Answer 8

male tails are incredibly long.
do females prefer long tails?
3 groups: shortened, normal, elongated tails
females preferred the elongated tails, meaning its a sexually selected trait despite its drawbacks (harder to fly, costly to produce/maintain, increased predation risk)

Question 9

what do females select for in song sparrows?

Answer 9

larger song repertoires

Question 10

what is unique about blue satin bowerbird’s courtship?

Answer 10

they make nests with “runways” in the middle, and collect as many blue things as they can for decoration.

Question 11

what do females gain when choosing for indirect benefits?

Answer 11

better genes for their offspring

Question 12

cryptic female choice (and ex.)

Answer 12

post-copulatory control of fertilization by females
(ex. differential ejection of sperm)

Question 13

pecking order in chickens

Answer 13

dominance is heritable, so females gain from mating with dominant males. will eject sperm of lower ranking males when mating with more dominant male.
dominant male will sometimes force copulation

Question 14

direct benefits

Answer 14

parenting, food, resources, good territory.

Question 15

indirect benefits

Answer 15

elaborate displays convey male quality, which can be inherited by offspring. Genetic quality often means disease resistance, genetic complementarity, and symmetry.

Question 16

Fisherian runaway selection model

Answer 16

trait has selective advantage, and will be selected to its extreme over and over, until the trait is too costly to produce/maintain, and females stop preferring it.

Females choose the ornamented males to ensure their sons will have the same reproductive success.

The genes for preferring the trait and having the trait are often bundled, since the mother prefers the trait and the father has it. Size of trait is correlated with degree of preference.

Question 17

good genes/handicap model

Answer 17

males with elaborate traits convey quality- if they are able to survive with these inconvenient traits, they must be a superior male.

The trait could also indicate good genes:
- genetic complementarity (high heterozygousity in offspring, should female mate with him)
- disease resistance
-foraging skills
- symmetry (if male was able to develop symmetrically, it means he was able to maintain normal development under stress)

Question 18

MHC

Answer 18

immune cell surface proteins. Recognizes foreign molecules in invertebrates, bind peptide fragments from pathogens and display them for T cells.

Females tend to choose males with diverse MHC genes.

Question 19

fluctuating asymmetry

Answer 19

bilateral symmetry is an indicator that the male developed normally in the face of stress.

Question 20

chase away selection

Answer 20

preference for trait evolved prior to sexually selected trait, which was evolved by males to exploit pre existing sensory biases of females. Female fitness declines in mating with these males, as this trait is not an indicator of quality, it is simply exploiting a sensory bias she already had for some other reason.
creates a loop where because her fitness declines, the female’s mating threshold increases for the trait.

Question 21

peacock study

Answer 21

males with more eyespots mated more often (eyespots where cut out)

males with longest tails also had a higher immune response when injected with PHA

Question 22

song sparrow study

Answer 22

males with larger repertoire sizes have greater immune response when injected with PHA.

Question 23

fluctuating asymmetry study

Answer 23

male fish had bars removed via dry ice, females didnt prefer them, when they were made symmetrical, females preferred them.

Question 24

guppies study

Answer 24

sensory bias in female guppies was tested using different coloured dishes, females preferred and pecked the orange dish much more than other colours.

Question 25

what is mate choice copying?

Answer 25

when a female chooses to mate with a male who clearly has already had mates. (ex. can clearly see eggs in his nest)

Question 26

when is it beneficial to mate choice copy?

Answer 26

when it is hard to discriminate mate quality
when cost of poor mate choice is high
allocare behaviour

Question 27

plain fin midshipman reproduction details

Answer 27

reproduce in intertidal zone
guarder males dig and defend nests, and hum to attract females. they provide all the paternal care.

females are attracted to humming, and larger males. they spawn once per season

Question 28

experiments in mate choice copying

Answer 28

females did not mate with the male with many females (possibly perceived as rejection)

female demonstrator experiment, females preferred spawning in the same nest as demonstrator.