Answer:
The change in sensitivity of female midshipman fish to the 'songs' produced by males of their species is a proximate example of stimulus filtering because it involves a physiological change in the female fish's auditory system that results in a selective response to certain sounds produced by the males.
Stimulus filtering refers to the process by which an organism's sensory system selectively responds to certain stimuli, while disregarding others. This can occur at different levels, including the level of the sensory receptors, the processing of sensory information in the brain, or the behavior of the organism.
In the case of the female midshipman fish, their sensitivity to the 'songs' produced by males of their species changes depending on their reproductive state. This change in sensitivity is a result of the females' auditory system becoming more sensitive to specific frequencies of the males' songs, while becoming less sensitive to others. This allows the females to selectively respond to only the most desirable males and disregard others.
Thus, the change in sensitivity of the female midshipman fish to the 'songs' produced by males of their species is a proximate example of stimulus filtering, as it involves a physiological change in the auditory system of the female fish that allows them to selectively respond to certain sounds.