Sensory receptors involved in the feeding behaviour of the rotifer Asplanchna brightwelli

A study of the anterior sensory receptors of male and female A. brightwelli by scanning elecron microscopy reveals some important differences in the region surrounding the mouth. In the male, the ventolateral sensory bristles, the pseudotrochus, the inner and outer buccal tufts and the mastax receptors are absent. The oral receptors are reduced. Transmission electron microscopy of these receptors shows that they consist of ciliated sensory cells surrounded by epithelial supporting cells. The distal ends of the cilia of the mastax receptors are modified; the cilia of the other receptors differ only in their length and rootlet structure from the locomotor cilia of the angulum. A consideration of the feeding behavior of Asplanchna leads us to suppose that these sensory cilia function in mechanoreception and in chemoreception.