lice and pigeon paper

Question 1

Harrisons rule

Answer 1

lice evolve to be the perfect size to fit between feather barbs, too big and they cant hide, too small and they cant run away easily

Question 2

Control

Answer 2

feral pigeons with naturally occurring lice removed (ensures the lice size change is an evolutionary response)

Question 3

results

Answer 3

Lice did increase in size, relative to the bird size - supports hypothesis

Question 4

Common garden experiment

Answer 4

proves louse body size is inheritable

Question 5

sexual dimorphism features in lice

Answer 5

Relative size and male antennae

Mismatched pairs can have males that are too big or too small

Question 6

effects of sexual dimorphism

Answer 6

Change in size leads to reproductive isolation and eventually allopatric speciation
Males always attempted to mate with females but when with a typical female rather than mismatched pair, copulation was 70% longer
More viable (92%) eggs were produced by typical pairs and more offspring were also produced by typical pairs than mismatch pairs.

Question 7

sexual selection…

Answer 7

…amplifies consequence of local adaptation for evolution of reproductive isolation

Sexual dimorphism means that sexual selection influences intrasexual competition (mate guarding and male fighting)

Question 8

Reproductive isolation leads to…

Answer 8

…reduced gene flow which could lead to adaptations between host and louse, could result in more reduced gene flow and reproductive isolation
only occurs when host size changes