Williams D S
Cell Tissue Res. 1982;225(3):595-617. doi: 10.1007/BF00214807.
In the compound eye of the locust, Locusta, the cross-sectional area of the rhabdoms increases at "dusk" by 4.7-fold due to the rapid assembly of new microvillar membrane, and decreases at "dawn" by a corresponding amount as a result of pinocytotic shedding from the microvilli. The rhabdoms at night have more and longer photoreceptor microvilli than rhabdoms during the day. The orientations of the six rhabdomeres that comprise the distal rhabdom also change. The density of intramembrane particles on the P-face of the microvillar membrane, putatively representing mostly rhodopsin molecules, or aggregates thereof, does not change. An alteration in the size of the ommatidial field-stop, produced by the primary pigment cells, is concomitant with the change in rhabdom size. At night the increase in size of the field-stop must widen the angular acceptance of a rhabdom, increasing the capture of photons from an extended field. Conversely, during the day, when photons are more abundant, its decrease must narrow the acceptance angle, increasing angular resolution. Because of the presence of this field-stop, the optics of the ommatidium would not be greatly affected if the rhabdom were to remain always at its night size. It is argued, therefore, that the variable-size rhabdom must have resulted from some demand other than that of light/dark adaptation. Changes in size and organisation of the rhabdoms in response to various light regimes indicate that: (1) Rapid shedding of photoreceptor membrane is induced by the onset of light, but shedding also occurs slowly in darkness during the day. (2) Microvillar assembly is initiated by the onset of darkness, but also occurs at the normal time of dusk without a change in ambient lighting, provided there has been some light during the day. Therefore, both shedding and assembly of microvillar membrane are affected by the state of illumination, but also appear to be under some endogenous control.
在飞蝗（Locusta）的复眼中，视杆的横截面积在“黄昏”时因新微绒毛膜的快速组装而增加4.7倍，而在“黎明”时由于微绒毛的胞饮性脱落而相应减少。夜间的视杆比白天的视杆具有更多更长的感光微绒毛。组成远端视杆的六个视小杆的方向也会改变。微绒毛膜P面上的膜内颗粒密度，推测主要代表视紫红质分子或其聚集体，并未改变。由初级色素细胞产生的小眼场阑大小的改变与视杆大小的变化同步。夜间场阑大小的增加必然会扩大视杆的角接受范围，增加从扩展视野中捕获的光子数量。相反，在白天光子较多时，场阑大小的减小必然会缩小接受角，提高角分辨率。由于存在这个场阑，如果视杆始终保持其夜间大小，小眼的光学性能不会受到太大影响。因此，有人认为，视杆大小可变一定是由光/暗适应以外的某种需求导致的。视杆在不同光照条件下大小和组织的变化表明：（1）光的开始会诱导感光膜的快速脱落，但在白天黑暗中也会缓慢发生脱落。（2）微绒毛组装在黑暗开始时启动，但如果白天有过一些光照，在正常黄昏时间也会发生，且环境光照没有变化。因此，微绒毛膜的脱落和组装都受光照状态的影响，但似乎也受某种内源性控制。
