Attachment of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) to artificial substrates in a natural environment

Abstract

Peritrich ciliates are commonly found as epibionts, colonizing living organisms, or attached to non-living substrates in freshwater, estuarine and marine environments. Several species of peritrich epibionts are obligate, which means that they are able to only colonize other organisms, while others are facultative attaching to living or non-living substrates. The peritrich Zoothamnium intermedium is commonly found as epibiont on the copepod species Acartia tonsa and Eurytemora affinis in Chesapeake Bay, USA. Previous studies demonstrated that Z. intermedium is not able to attach to non-living substrates in the laboratory; with free-swimming stages (telotrochs) dying when living substrates are not available for colonization. The present study investigated the ability of Z. intermdium to colonize artificial substrates in the field. Observations were carried out while the peritrich ciliate was colonizing copepods in Rhode River, a tributary of Chesapeake Bay. Results demonstrated that four species of Zoothamnium were recovered from artificial substrates, but none of them was Z. intermedium. At the same time, Z. intermedium was colonizing adults and copepodites of E. affinis and A. tonsa during the whole study period. These results, in addition to laboratory observations, suggest that Z. intermedium is an obligate epibiont.Keywords: ciliates, comensalism, Acartia tonsa, copepods, epibiosis Colonização de substratos artificiais pelo peritríquio epibionte Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia), em um ambiente natural ResumoCiliados peritríquios são normalmente encontrados como epibiontes, colonizando substratos vivos, ou em substratos inanimados em ambientes de água doce, estuarinos e marinhos. Muitas espécies de peritríquios epibiontes podem ser consideradas obrigatórias quando estão aptas a colonizar apenas substratos vivos, ou facultativos quando conseguem colonizar substratos vivos ou inanimados. A espécie de ciliado peritríquio Zoothamnium intermedium é encontrada colonizando os copépodos Acartia tonsa e Eurytemora affinis na Chesapeake Bay, EUA. Estudos preliminares demonstraram que Z. intermedium não consegue colonizar substratos inanimados em laboratório e que os estágios livre-natantes (telotróquios) morrem quando não estão expostos a algum substrato vivo. No presente estudo, foi investigada a habilidade de Z. intermedium colonizar substratos artificiais no campo. As observações foram realizadas no Rhode River, um afluente da Chesapeake Bay, enquanto Z. intermedium era encontrado colonizando copépodos. Os resultados demonstraram que quatro espécies de Zoothamnium colonizaram os substratos artificiais, mas nenhuma delas era Z. intermedium. No mesmo período, Z. intermedium foi encontrado colonizando copepoditos e adultos de A. tonsa e E. affinis. Estes resultados, juntamente com as observações de laboratório, sugerem que Z. intermedium é um epibionte obrigatório.

Ciliate Epibionts Associated with Crustacean Zooplankton in German Lakes: Distribution, Motility, and Bacterivory

“…Additionally, the high individual clearance rate and ingestion rate of the epibionts mean that each ciliate processed a large amount of bacterial biomass. Utz (2008) reported that at a food concentration of 10 6 bacteria ml −1 , comparable to our experimental food concentrations, the epibiont ciliate Zoothamnium intermedium attained a growth rate as high as 0.8 day −1 . An even higher in situ growth rate (1.37 day −1 ) has been reported for benthic peritrich ciliate (Kusuoka and Watanabe, 1987).…”

Niche relations in a small world: Epizoic algae on an intertidal gastropod

“…Many sessile organisms are known as substrate specialists, especially in the case of obligate epibionts (Bordeaux & Brett, 1990; Callaway, Reinhart, Moore, Moore, & Pennings, 2002; Fontaneto & Ambrosini, 2010; Frick, Kopitsky, Bolten, Bjorndal, & Martins, 2011; Matsuyama, Aruga, & Tanaka, 1999; Utz, 2008). In relying upon naturally limited spatial niches, epibionts need to cope with changing conditions of substrates, depending on host morphology, behavior and growth (e.g., Abbott & Bergey, 2007; Bell, 2005; Callaway et al, 2002; Fontaneto & Ambrosini, 2010; Pfaller, Bjorndal, Reich, Williams, & Frick, 2008; Vasconcelos, Cúrdia, Castro, & Gaspar, 2007; Wagner & Zotz, 2020; Woods, Cardelús, & DeWalt, 2015).…”