Vol. 57, 2018
(update: 2018.09.03; 10.17)
Diversity and Distribution of
Peritrich Ciliates on the Snail Physa
acuta Draparnaud, 1805 (Gastropoda: Physidae) in a Eutrophic
Lotic System
Bianca
Sartini1, Roberto Marchesini1,
Sthefane D'ávila2, Marta
D’Agosto1, and
Roberto Júnio Pedroso Dias1,*
doi:10.6620/ZS.2018.57-42
1Laboratório
de Protozoologia, Programa de Pós-graduação em Ciências Biológicas
(Zoologia), ICB, Universidade Federal de Juiz de Fora, Juiz de Fora,
Minas Gerais, 36036-900, Brazil
2Museu de Malacologia Prof. Maury Pinto de Oliveira,
ICB, Universidade Federal de Juiz de Fora, Minas Gerais, 36036-900,
Brazil
(Received 9 September 2017; Accepted 26 July
2018; Communicated by Benny K.K. Chan)
Bianca
Sartini, Roberto Marchesini, Sthefane D´ávila, Marta D’Agosto, and
Roberto Júnio Pedroso Dias (2018) Freshwater
gastropods represent good models for the investigation of epibiotic
relationships because their shells act as hard substrates, offering a
range of microhabitats that peritrich ciliates can occupy. In the
present study we analyzed the community composition and structure of
peritrich epibionts on the basibiont freshwater gastropod Physa acuta.
We also investigated the spatial distribution of these ciliates on the
shells of the basibionts, assuming the premise that the shell is a
topologically complex substrate. Among the 140 analyzed snails, 60.7%
were colonized by peritrichs. We observed seven peritrich species: Epistylis plicatilis and Epistylis sp. (Epistylididae); Opercularia articulata
(Operculariidae); Carchesium polypinum, Vorticella campanula and Vorticella sp. (Vorticellidae) and Thuricola kellicottiana
(Vaginicollidae). We observed a high prevalence of epibiosis (> 60%)
when all species of ciliates were considered conjunctly. However, the
prevalence was low (1-58%) when each species was considered separately,
reflecting their aggregate distribution pattern. The most prevalent
species were Epistylis sp.
(58.60%), Vorticella sp.
(14.30%) and O. articulata
(13.60%). Although the epibionts were distributed through the shell’s
entire extension, we observed
greater values of abundance, density, diversity and dominance on the
dorsal surface. Only Epistylis
sp. was widely distributed on the ventral surface. We also observed
that the peritrichs predominantly occupied the areas of the shell
delimited by the sutures. We interpreted these distribution patterns
considering that the peritrichs select their attachment sites under
pressures related to basibiont behavior, physical forces that may
dislocate them and protective characteristics of the shell’s areas.
Key words: Brazil, Peritrichia, Physa acuta, Protozoan epibionts,
Site preference.
*Correspondence: Tel: +55 32 21023223. E-mail:
rjuniodias@hotmail.com

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