Cannibalism in lower eukaryotes

Abstract

Abstract Cannibalism is taxonomically widespread among lower eukaryotes (Sandon 1932), although most reports have been anecdotal. The first report of cannibalism in lower eukaryotes was in the ciliateOxytricha(Haime 1853). It was subsequently reported in several other species of ciliates, includingOnychodromus grandis(Maupas 1888),Pleurotricha laceolata(Joukowsky 1898),Stentor coeruleus(Gelei 1925),Blepharisma undulans(Dawson 1929), andStylonychia curvata(Giese and Alden 1938). Although generally widespread among the ciliates, it is notable that cannibalism has not been reported for the most commonly studied smaller ciliatesTetrahymenaandParamecium,which generally feed upon bacteria. However, two species,Tetrahymena vorax(Buhse 1966; Buhseet al.1978) andT. patula(Williams 1960) can undergo a transformation from a form which feeds upon bacteria to a carnivorous form which feeds on other cilates. The transition to the large form capable of feeding upon larger prey involves the resorption of the oral apparatus and the formation of a larger one by a process known as oral replacement. Cannibalism does occur in the form with the larger oral apparatus (N. E. Williams, personal communication).