Clayton and colleagues discovered the relationship between feather-louse size and the body mass of their corresponding bird hosts illustrated in the figure below.What do the authors hypothesize about the mechanism of cospeciation in doves and lice from this relationship?
A)Lice are unlikely to switch to hosts that differ in body size from their original host.
B)Lice will tend to shift to the larger host regardless of their own size.
C)Larger lice are always better at holding onto their hosts.
D)Smaller lice are always better at evading the preening attempts than large lice species.

Question

Clayton and colleagues discovered the relationship between feather-louse size and the body mass of their corresponding bird hosts illustrated in the figure below.What do the authors hypothesize about the mechanism of cospeciation in doves and lice from this relationship? 
A)Lice are unlikely to switch to hosts that differ in body size from their original host. 
B)Lice will tend to shift to the larger host regardless of their own size. 
C)Larger lice are always better at holding onto their hosts. 
D)Smaller lice are always better at evading the preening attempts than large lice species.

Quizplus · Accepted Answer

The relationship between feather-louse size and bird body mass suggests a strong coevolutionary relationship between the two species. Specifically, the fact that lice tend to stay with hosts of similar body size suggests that lice are unlikely to switch to hosts that differ in body size from their original host. This is consistent with the mechanism of cospeciation, whereby closely associated species evolve in concert with each other over time.

Clayton and Colleagues Discovered the Relationship Between Feather-Louse Size and the Body