Reading 4.1 Albo et al

Question 1

Hypotheses

Answer 1

• The nuptial gift is a target of cryptic female choice in the polyandrous spider Pisaura mirabilis (Pisauridae).
  • In species in which nuptial gifts facilitate mating, females may gain indirect benefits through preferential storage of sperm from gift-giving males if the gift signals male quality.

Question 2

The study prediction

Answer 2

• If females bias sperm storage towards males that offer a gift, females in the GT group were expected to store more sperm than females in the NG group

Question 3

What other species provide nuptial gifts?

Answer 3

• Hanging flies and Mormon crickets

Question 4

When did the study take place

Answer 4

May 2011

Question 5

What food source was using to make a nuptial gift?

Answer 5

A housefly

Question 6

What were the three study conditions?

Answer 6

• Experimentally terminated copulation in males with a gift (matching males with no gift)
• Males with no gift
• Males with a gift and uninterrupted copulation

Question 7

How was postcopulatory cryptic choice measured?

Answer 7

Sperm were counted

Question 8

What else was examined in the study?

Answer 8

The effect of gift presence and copulation duration on female fecundity and egg-hatching success

Question 9

Study results

Answer 9

• The sperm count in the female spermatheca differed significantly among the three experimental groups

Was significantly lower in the NG group compared with the GT group even with copulation length being consistent

Question 10

Why might females prefer nuptial gift providing males?

Answer 10

• Females gain indirect benefits, eg they produce sons likely to provide nuptial gifts etc

Question 11

Results in regard to the hypothesis

Answer 11

• Sperm storage is partially under female control through cryptic sperm choice
  • egg hatching success was significantly higher in mating with gift-giving compared with gift-less males
• Confirms the prediction that the nuptial
  gift as a male signal is under positive sexual selection by females through
  cryptic sperm storage

Question 12

What are the two advantages of providing a nuptial gift?

Answer 12

• Two advantages of nuptial gift - Firstly, nuptial gifts are favored by cryptic female choice as females store more sperm from gift-giving males. Secondly, gift-giving males increase the number of sperm transferred by prolonging copulation

Question 13

Future study could…?

Answer 13

Examine whether internal processes that mediate sperm activation and fertilisation are targets for postcopulatory female choice

Question 14

Why was the study carried out?

Answer 14

• There is little evidence for female-mediated cryptic sperm choice