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(Imai & Rung, 1990a; Van Hoven et al., 1978), and in water buffalo (Dehority, 1979), to over 500,000 ml \u22121 in musk oxen (Dehority, 1985) and in some deer species (Dehority, 1990, 1995; Ito et al., 1993). Abundances of ciliates in non-ruminants have a sim- ilar range: cycloposthiids numbered up to 700 ml \u22121 in the cecum of the capybara , representing about 30% of the ciliate fauna (Ito & Imai, 2000a, 2000b); over 10,000 ml \u22121 throughout the intestinal tract of African elephant (Eloff & Van Hoven, 1979); typi- cally over 100,000 ml \u22121 in the colon of rhino ceroses (Gilchrist et al., 1994) and caecum of horses (Bonhomme-Florentin, 1994); and abundances of ophryoscolecids of around 1,000,000 ml \u22121 in collared peccary (Carl & Brown, 1983). The rumen ciliates have diverse interactions with the bacterial and fungal communities and with each other. Bacteria are the foundation of the rumen eco- system, colonizing substrates minutes after inges- tion and forming cellulolytic consortia that digest the plant tissues (McAllister, Bae, Jones, & Cheng, 1994). While most rumen ciliates ingest bacteria as a source of nitrogen , Entodinium species are particularly important predators of bacteria, con- suming more than 10 5 bacteria per ciliate per hour (Coleman, 1989; Williams, Joblin, Butler, Fonty, & Bernalier, 1993). Entodiniomorphids are able to ingest plant fragments and digest these using their own cellulolytic enzymes (Akin & Amos, 1979; Bauchop, 1979; Benyahya, Senaud, & Bohatier, 1992; Bohatier, Senaud, & Benyahya, 1990; Grain & Senaud, 1985; Michalowski, Belzecki, Kwiatkowska, & Pajak, 2003; Stan, Belzecki, Kasperowicz, 9.2 Life History and Ecology 193 194 9. Subphylum 2. INTRAMACRONUCLEATA: Class 3. LITOSTOMATEA Kwiatkowska, & Michalowski, 2006), and even chitin (Belzecki & Michalowski, 2006). Polysaccharides are stored as amylopectin , either as skeletal plates or as cytoplasmic particles. Eadie (1967) was one of the first to recognize that there were some ciliates that were consistently common in the rumen , namely Entodinium spp., Isotricha spp. and Dasytricha ruminantium while others varied. Eadie (1967) identified two assemblages, Type A and Type B. The Type A assemblage included Polyplastron multivesiculatum , Diploplastron aff- ine , and Ophryoscolex tricoronatus , while the Type B assemblage included Eudiplodinium mag- gii , Epidinium spp., Eremoplastron spp., and Ostracodinium spp. The Type A assemblage typi- cally displaces Type B as the former includes some predators of the latter (Eadie; Imai, Katsuno, & Ogimoto, 1979). Eudiplodinium maggii may be induced to develop to a larger size in the pres- ence of its predator Polyplastron multivesiculatum (Eadie, 1979). Polyplastron multivesiculatum , E. maggii , and Entodinium sp. may also ingest fungal zoospores and rhizoids (Williams et al., 1993). Finally, Isotricha and Dasytricha species preferen- tially ingest starch grains . This feeding habit may provide a more stable rumen pH since it prevents the more rapid bacterial fermentation of starch to lactic acid , which may lead to lactic acid acidosis (Williams, 1986). Since most of the ciliates are retained in the rumen (Bonhomme-Florentin, 1994; Williams, 1986), ciliate biomass contributes little to host metabolism. Moreover, although both ciliates and bacteria are highly cellulolytic , bacterial activ- ity can entirely replace the ciliate activity (Hidayat, Hillman, Newbold, & Stewart, 1993). Although there are contradictory reports, typically defauna- tion or removal of the ciliates has little or no impact on host growth (see reviews of Bonhomme, 1990; Jouany, 1994; Veira, 1986; Williams, 1986). Some recent research has demonstrated that defaunation improves ruminal nitrogen metabolism to the host (Ivan, Neill, & Entz, 2000; Koenig, Newbold, McIntosh, & Rode, 2000). Bonhomme-Florentin (1994) noted that there is very little research on the importance of the ciliates of non-ruminant and primate hosts. Like their rumen relatives, Cycloposthium and Didesmis associate with plant fibres in the caecum of the horse, aiding in the digestion of these fibres (Bonhomme-Florentin, 1985). However, Moore and Dehority (1993) concluded that ciliates do not play an essential role in the equine hindgut : defau- nation of the caecum and colon had no effect on levels of cellulose digestion . One major impact of defaunation is reduction of methane production by the ruminant . Like the sapropelic armophoreans (see Chapter 8 ), metha- nogenic bacteria are associated as epibionts on entodiniomorphids (Krumholz, Forsberg, & Veira, 1983; Stumm, Gijzen, & Vogels, 1982) and as endosymbionts in vestibuliferidans (Finlay et al., 1994). These methanogens have been assigned to the genera Methanobrevibacter , Methanosphaera , and Methanosarcina (Hillman, Lloyd, & Williams, 1988; Tokura, Chagan, Ushida, & Kojima, 1999). Adult cattle can produce from 300\u2013600 l of methane per day, translating to 80 million tonnes of methane worldwide (Jouany, 1994). This methane produc- tion may represent the greatest source of methane production in the European Union (Moss, Jouany, & Newbold, 2000) and over 50% of the methane emissions in Australia (Klieve & Hegarty, 1999). Defaunation to reduce methane production is thus a major priority in the context of global warming . Adding coconut oil to artificial rumen fermenters reduced methane formation by 40% (Dohme et al., 1999) while the common food preservative, nisin , reduced methanogen production by 36% (Klieve & Hegarty, 1999). There are other strategies for elimi- nating the protozoa, but as yet none have reached commercialization (Hegarty, 1999). With the exception of Balantidium , trichostome ciliates do not form cysts . Thus, transmission from one host to the other must take place by various forms of contamination . Rumen ciliates and those in the forestomach of the host are transferred by salivary contamination from mother to offspring and contamination of drinking water (Bonhomme- Florentin, 1994; Van Hoven, 1978). Entodinium is typically the first rumen ciliate to appear (Crha, St\u159í\u17e, Sk\u159ivánek, & Valach, 1991). Young horses become infected by actively eating the mothers\u2019 feces in the first week of life (Ike, Imai, & Ishii, 1985). It is not yet known how the macropodiniids are transmitted between marsupial hosts, although maternal grooming of the young may be a typical route (Cameron & O\u2019Donoghue, 2003b). The feeding preferences and strategies of lito- stomes are quite diverse. As noted above for the trichostomes , bacteria and plant material can be prey items in addition to other ciliates. The hap- torians can be typified as fast-swimming, active and voracious predators, showing marked prefer- ences for flagellates and other ciliates, even to becoming cannibalistic . Dragesco (1962) used high speed cinematography to provide some detailed descriptions of predation by Enchelys , Litonotus , Chaenea , Didinium , and Dileptus on other ciliates, like Colpidium . Feeding by Dileptus may even be entrained to a daily rhythm (Miller, 1968). This preference of haptorians for flagellates and other ciliates has been confirmed by others (e.g., Dolan & Coats, 1991b; Estève, 1982; Foissner & Leipe, 1995; Foissner, Berger, & Schaumburg, 1999; Johnson, Donaghay, Small, & Sieburth, 1995). In an ingenious series of experiments, Karpenko, Railkin, and Seravin (1977) used magnetic moving models to demonstrate that Didinium and Dileptus responded to prey movement, somehow sensing hydrodynamic disturbances of the medium. This sensitivity to hydromechanical signals has been confirmed for Mesodinium pulex , which probably uses its bristle girdle as the \u201cdetector\u201d