Mate guarding, sperm competition and sexual conflict

Question 1

What is the primary goal of sexual selection in males?

Answer 1

To maximise their paternity, even after mating

Question 2

What is Parentage assurance?

Answer 2

evolved mechanisms to increase one’s chances of being the parent of offspring:
1.) Mate guarding
2.) Sperm competition
3.) Sexual conflict

Question 3

What is mate guarding?What is the ultimate aim?

Answer 3

when one sex (typically male) prevents same-sex competitors having access to it’s mate (in an attempt to achieve reproductive monopoly of mate).

Question 4

Name an example of Pre-copulatory mate guarding

Answer 4

Pupal mating in Heliconius butterflies where males search for females on host plant and compete for the possession of pupa (no female choice involved).

Question 5

What are the two main types of mate guarding?

Answer 5

Pre-copulatory and post-copulatory mate guarding

Question 6

What is sperm competition?

Answer 6

Competition for fertilizations by sperm from different males within a single female’s reproductive tract.

Question 7

How do males ensure parentage assurance?

Answer 7

Through mechanisms like mate guarding, sperm competition, and decreasing female receptivity

Question 8

What is a mating plug?

Answer 8

A structure left by a male after mating to prevent reinsemination by other males.

Question 9

In which species was a significant percentage of male matings found to fail due to recent mating?

Answer 9

Locusts (Locusta migratoria).

Question 10

What is the effect of mating plugs on female mating success?

Answer 10

They can significantly decrease the likelihood of successful subsequent matings.

Question 11

What role do sperm scrapers play in sperm competition?

Answer 11

They allow males to remove rival sperm from the female’s reproductive tract.

Question 12

What is the significance of the last male to fertilise a female?

Answer 12

The last male typically gains the most fertilisations of eggs

Question 13

How do cooperative sperm work in wood mice?

Answer 13

50-100 sperm form a ‘train’ to enhance speed and fertilization efficiency.

Question 14

What is sexual conflict?

Answer 14

An evolutionary conflict arising between sexes due to differing fitness optima.

Question 15

How does mating affect female longevity in Drosophila melanogaster?

Answer 15

Mating can decrease female longevity due to toxic effects of male seminal fluid.

Question 16

What is the relationship between testis mass and sperm competition?

Answer 16

There is a positive correlation; larger testis mass often indicates higher levels of sperm competition.

Question 17

What is the evolutionary rationale behind male manipulation of female receptivity?

Answer 17

Males may manipulate females to decrease receptivity to secure their paternity.

Question 18

What is the benefit of pre-copulatory mate guarding?

Answer 18

It ensures that the male is present when the female becomes receptive, thus securing paternity

Question 19

Why might mate guarding be costly for males?

Answer 19

It can involve risks like predation, loss of feeding opportunities, and missed chances to find other mates

Question 20

What is the mating strategy of Heliconius butterflies?

Answer 20

Males guard female pupae to mate as they emerge.

Question 21

What is the role of seminal fluid peptides in Drosophila melanogaster?

Answer 21

They boost male fertilisation success, increase female egg production, and decrease female receptivity

Question 22

How do male damselflies compete for fertilisation?

Answer 22

They use spines on their secondary genitalia to scrape out rival sperm.

Question 23

What is the significance of cooperative sperm in murine rodents?

Answer 23

They show variations in sperm shape and curvature, which correlate with testis mass and competition intensity.

Question 24

What is the mating behaviour of the Yellow Dung Fly?

Answer 24

Males mount females post-copulation to prevent sperm displacement by other males.

Question 25

What is the cost of mate guarding to males?

Answer 25

-cost of feeding -cost of increased risk of predation -cost of lost opportunities to find other females close to their receptive period

Question 26

Name an example of post-copulatory mate guarding

Answer 26

-Pondskater--> precopulatory phase (1.5 min) plus copulation (16.2 min) -Postcopulatory phase (male rides passively on the back of the female without genital contact (11 min--> 48 h)

Question 27

How is Post-copulatory mate guarding favoured?

Answer 27

-Females remain receptive post copulation (hence mating with new male is possible) -Interval between copulation and egg-laying is short hence guarding male doesn't have to guard for too long -finding mates is easier (encountering is high). -last male to fertilise female gains most fertilisations of eggs (hence new male would gain paternity of young at expense of original male).

Question 28

Name another example of post-copulatory guarding

Answer 28

Canids but where is high predation risk

Question 29

How does polyandry affect sperm competition?

Answer 29

Females mating with multiple males increases competition among sperm for fertilization

Question 30

What is the expected outcome of sexual conflict in mating systems?

Answer 30

It often leads to males favoring short-term female health to maximise their reproductive success

Question 31

What is the relationship between mating systems and sexual conflict?

Answer 31

The occurrence of sexual conflict depends on mating systems, social systems, and relatedness structures.

Question 32

What is the significance of the cooperative behaviour of sperm in competition?

Answer 32

It enhances the chances of fertilisation by working together against unrelated sperm.

Question 33

What does the term "mating plugs" refer to in locusts?

Answer 33

Structures that prevent females from mating again shortly after a successful mating

Question 34

Give an example of mating plugs

Answer 34

-26% of male matings fail if female has recently mated -successful matings still last 4 times longer than matings with females --> mating males leave a mating plug to prevent reinsemination

Question 35

How do males in some species manipulate female fitness?

Answer 35

By transferring substances that can decrease female longevity and receptivity.

Question 36

What is the benefit of post-copulatory mate guarding?

Answer 36

It protects the male's sperm from being displaced by subsequent matings.

Question 37

What is the evolutionary interest of a male in the short-term welfare of a female?

Answer 37

To ensure she remains healthy long enough to lay the eggs he has fertilised.

Question 38

How does the mating behaviour of males in species like crickets illustrate sperm competition?

Answer 38

Males with smaller, more numerous sperm tend to father more offspring when competing with others.

Question 39

What is Sexual selection a balance of?

Answer 39

male-male competition and female choice

Question 40

What does sexual selection give males?

Answer 40

a platform to show females their traits where females ultimately choose to create the next generation of offspring

Question 41

What is Sperm competition?

Answer 41

competition for fertilisations by sperm from different males within a single female's reproductive tract

Question 42

What is Sperm competition driven by?

Answer 42

selection on each male to maximise his paternity

Question 43

How does a mating plug function in locusts?

Answer 43

In locusts (Locusta migratoria), successful matings last about four times longer than unsuccessful ones, and males leave a mating plug to prevent females from mating again

Question 44

How do male damselflies engage in sperm competition?

Answer 44

Male damselflies use spines on their secondary genitalia to scrape out the sperm of rival males from the female's reproductive tract.

Question 45

What is the significance of testis mass in birds regarding sperm competition? What does this indicate?

Answer 45

There is a significant positive correlation between relative testis mass and the level of extra-pair paternity, indicating that males with larger testes produce more sperm and have a higher chance of fertilisation

Question 46

Describe the cooperative sperm behaviour observed in Wood Mice

Answer 46

In Wood Mice (Apodemus sylvaticus), 50-100 sperm can form a 'train' using hooks on their heads or entwined tails, which gives them a speed advantage over single sperm.

Question 47

How do males of Drosophila melanogaster manipulate female fitness?

Answer 47

Males transfer peptides in seminal fluid that boost their fertilization success, increase female egg production in the short term, but decrease female receptivity and longevity in the long term

Question 48

What is the evolutionary rationale behind male manipulation of female receptivity?

Answer 48

Males may manipulate female receptivity to prevent her from mating with other males, thus ensuring their paternity, even if it shortens her lifespan

Question 49

Why is the duration of mate guarding a compromise for males?

Answer 49

The duration and frequency of mate guarding balance the costs of not feeding, increased predation risk, and lost opportunities to find other receptive females.

Question 50

What is the relationship between sperm size and quantity in the context of sperm competition?

Answer 50

The evolution of numerous, small, motile sperm and larger testes is driven by the need to maximize the chances of fertilization in competitive environments.