Sexual Selection Studies

Question 1

Keagy et al. (2009)

Answer 1

Tested whether general cognitive performance in male bowerbirds plays a role in sexual attractiveness. They did this by designing problem-solving tasks related to the birds’ aversion to red objects in their bowers. It was found that there is a positive relationship between male problem-solving ability and mating success. This could occur by females being influenced by traits which are correalted with problem solving ability for example song complexity has been related to learning a foraging task, and song complexity is known to influence mate choice. It could also occur through males that are better problem solvers being able to influence females choosing them as mates better.

Question 2

Petrie (1994)

Answer 2

Conducted a controlled breeding experiment where females were randomly assigned males and all offspring were reared under the same conditions. It was found that offspring of peacocks with more elaborate trains grow and survive better.

Question 3

Akre et al. (2011)

Answer 3

Tested whether psychophysical laws explain how female tungara frogs and frog-eating bats compare male frog calls and how this imposes selection on call evolution. Although both prefer more elaborate calls they are less selective as elaboration increases because preference is based on stimulus ratio.

Question 4

Andersson (1982)

Answer 4

Conducted classic experiments on the long-tailed widowbird to test female choice. The males of this species have remarkably long tails whereas the females have short tails. He manipulated groups of birds, some had a decreased tail-length, some had an increased tail-length, some were untouched and some were cut off and clued back on to control for tampering. Before these manpipulations there was no different in mating success. Afterwards however, the long-tailed birds did significantly better than the other groups. The increased success of the elongated-tail group reflected female choice.