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

Dale 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 than larger lice species at evading the preening attempts.