Effect of light and dark adaptation upon the rhabdom in the compound eye of the mosquito

Abstract

Abstract During the first two hours of light adaptation rhabdom volume in compound eyes of adult mosquitoes is strikingly reduced. In females this involves a net loss of photoreceptor membrane of 500–700 μ 2 /cell/hour. Concurrently, numerous coated vesicles and multivesicular bodies appear in the cytoplasm adjacent the rhabdom. After longer illumination times (up to 5 hours) membrane loss averages considerably less, 220 μ 2 /cell/hour. Furthermore, puromycin experiments suggest that it is counter‐balanced by the formation of an equal amount of new membrane. Thus, despite substantial membrane turnover no net change in rhabdom volume takes place. When light‐adapted mosquitoes are dark adapted for 12 to 36 hours there occurs a net increase of rhabdom membrane averaging 75 μ 2 /cell/hour, and a corresponding increase in rhabdom volume.