Comparing the retinal structures and functions in two species of gulls (Larus delawarensis and Larus modestus) with significant nocturnal behaviours.

摘要: Abstract Ring-billed gulls ( Larus delawarensis ) and gray modestus are two species active both by day night. We have investigated the retinal adaptations that allow diurnal nocturnal behaviours of these species. Electroretinograms histological analyses show a duplex retina in which cones outnumber rods, but number rods appears sufficient to provide vision at Their retinas respond over same scotopic dynamic range 3.4 log cd m −2 , encompasses all light levels occurring night their photic environment. The amplitudes saturated a- b-wave responses as well photopic response sensitivity parameter S however higher ring-billed than gulls. Moreover, process dark adaptation is about 30 min faster Our results suggest acquired course evolution functional can be related specific