Mating Systems I

Question 1

What are the four major types of mating systems?

Answer 1

Monogamy, polygyny, polyandry, promiscuity

Question 2

What two factors determine the type of mating system? What species is an example of every type of mating system?

Answer 2

1. Male and female dispersion in space/time (mate access)
2. Patterns of desertion by either sex (c/b of parental care)
3. Dunnocks (each island has different system)

Question 3

What is the two-step process that leads to mating systems without any male parental care?

Answer 3

1. Female reproductive success limited by access to resources (she does all the work so female distribution depends on where the resources are)
2. Male success is limited by access to females (so males distribute according to female access (compete for females or resources for females))

Question 4

How does resource patchiness effect the type of mating system that arises? How does the OSR and breeding synchrony effect this? What is an example?

Answer 4

Evenly distributed patches = monogamy (hard to defend resources or multiple females)

Patchy = polygamy (easier to defend resources/females/both)

OSR = 1:1 and synchrony then females will breed before male can mate multiple times so monoooooo

Common toads are explosive breeders (males can’t mate with more than 2 females)

Question 5

What are examples of female dispersion being the deciding factor in male dispersion (2)?

Answer 5

1. Voles - abundant food –> smaller female ranges that overlap –> males at the sites

To determine if this was bc of food or females:

Females in cages on island and moved them around to simulate movement (regardless of food abundance). Found that when females clump, males clump and when they disperse, males disperse (following females) (males in cages = no effect on females)

2. Comparative study in mammals (will talk about it on another card)

Question 6

Elaborate on the comparative evidence in mammals that female dispersion drives male dispersion. What are the 3 main drivers of female monopolization? There are four scenarios. Explain each scenario with examples.

Answer 6

1. Female group size, female home range size, seasonality of breeding
2. Solitary female: range defensible by male - small female ranges = polygyny as males can defend multiple females : large female ranges = monogamy bc he can only defend one : No male parental care (aside from monogamous species)

Examples: Felids (small litters, polygynous), canids (large litters, monogamous), marmosets (monogamous w/ male parental care, female abandons without him)

3. Solitary female: range not defensible - females wander a range, males associate with females in estrous (orangutans)
4. Social females : defensible range - females band in small groups, male defends harem (kills young) (Hanuman langurs), if females in a large groups then there may be several males (lions)
5. Social females : range not defensible - predictable movement = males can defend route (topi), unpredictable movement = small group = males rove, larger group = males defend harem (buffalo)

Question 7

What is a lek? What are three examples of species that lek? In what types of species is lekking common?

Answer 7

1. Group of males and each male has a small territory where he advertises for females
2. walrus, grouse, hummingbirds
3. Frogs/toads/some insects

Question 8

What are the five hypothesis as to why males lek? What is an example of each?

Answer 8

1. Males aggregate to hot spots (female encounter rate high) (sandfly at vertebrate hosts with females)
2. Males aggregate to hotshots (low quality ass. with high quality so long as there’s no territory ownership) (bullfrogs)
3. To reduce predation risk (dilution effect) (tungara frogs get eaten by bats) (not a huge determinant in birds)
4. To increase female attraction (tungara frogs, linear = no male advantage (1 female per male))
5. Females prefer leks because they facilitate mate choice (offering safe mating and genetic benefits) (black grouse display = survival)