Ocular changes accompanying eye loss in the spider family uloboridae

In uloborid spiders, eye loss is accompanied by increased visual angles, optical material investment, and potential visual acuity of the retained eyes. Relative to carapace volume, the six-eyed Hyptiotes cavatus and two four-eyed Miagrammopes species have greater retinal hemisphere areas and lens volumes than do the eight-eyed uloborids Waitkera waitkerensis, Uloborus glomosus, and Octonoba sinensis. In Waitkera, in which the eyes have little visual overlap, and in Miagrammopes, in which eye loss simplifies the spiders' patterns of visual overlap, increased retinal cell density enhances potential visual acuity. However, this occurs at the expense of potential retinal cell sensitivity.