Note
Mesopelagic crustaceans occupy a dim-light environment that is similar to that of nocturnal insects. In a
light-limited environment, the requirement for greater sensitivity may result in slower photoreceptor
transduction and increased summation time. This should be reflected by a lower temporal resolution, as
indicated by a lower critical flicker fusion frequency (CFF). Therefore, one would predict that the CFFs
of mesopelagic organisms would be relatively low compared with those of their shallow-water relatives,
just as nocturnal insects tend to have lower CFFs than diurnal insects.