Ciliate Epibionts Research Articles

CILIATE (PROTOZOA) EPIBIONTS OF DEEP-WATER ASELLOTE ISOPODS (CRUSTACEA): PATTERN AND DIVERSITY

Abstract Examination of 32 species from seven families of marine asellote isopods (Crustacea, Malacostraca) showed that 15 of these species were infested with ciliate epibionts. The diversity of the ciliate epibiosis was fairly high (mean = 3.8 epibiont ciliate species per host species; range 1 to 10 species). Ciliates were absent from species of the family Janiridae and were rare on desmosomatids. The prevalence was high (≥ 37%) on two ischnomesid species (Ischnomesus norvegicus and Heteromesus frigidus), and on three munnopsid species (genus Ilyarachna). Mean intensity was fairly low (1.3–10.5) overall, but high on I. norvegicus (29.2). Some ciliate species showed host preferences. Predatory ciliates (subclass Suctoria) were most common on host species of the families Munnidae and the Nannoniscidae and some of the Ischnomesidae species, whereas suspension-feeding ciliates (subclass Peritrichia) were found on six host species only, belonging to the family Ischnomesidae or the subfamily Ilyarachninae (Mun...

Ciliate epibiont effects on feeding, energy reserves, and sensitivity to hydrocarbon contaminants in an estuarine harpacticoid copepod

Although epibiotic protozoans are commonly observed on the chitinous exoskeleton of aquatic crustaceans, relatively little is known about their ecological significance. The significance of protozoan epibionts on benthic copepods has never been examined.Coullana sp., a meiobenthic harpacticoid copepod, is abundant in Louisiana salt marshes and has high incidence (∼50%) of ciliate epibionts. Field and laboratory grazing experiments indicated that ciliate epibionts did not hinderCoullana feeding on benthic or planktonic algae. Contrary to expectations,Coullana with high levels of ciliate epibionts (>8 ind−1) grazed at a significantly higher rate on14C-labeled benthic diatoms added to intact sediment cores than didCoullana with no epibionts.Coullana neutral lipids (examined using Nile Red, a hydrophobic fluorophore) were not significantly influenced by the presence of ciliate epibionts, suggesting that copepods are able to compensate for any additional energetic demands imposed by epibionts. Epibiont effects onCoullana susceptibility to hydrocarbon contaminants were measured by examining survivorship in diesel-spiked sediments. The presence of ciliate epibionts significantly decreased survivorship at relatively low PAH concentrations (12.8 ppm). While ciliate epibionts onCoullana do not dramatically alter total food acquisition or energy storage, they may cause stress, which in turn makesCoullana more susceptible to contaminants and possibly other natural stressors such as food limitation.

Redescription of Vorticella oceanica Zacharias, 1906 (Ciliophora: Peritrichia) with notes on its host, the marine planktonic diatom Chaetoceros coarctatum Lauder,1864

Species of the marine planktonic diatom Chaetoceros were collected over a three year period from Otsuchi Bay, Japan. The vertical distribution of Chaetoceros spp. over a 40 m depth was investigated. One species, C. coarctatum, was found to have chloroplasts of two different shapes. Chaetoceros coarctatum was also the only species found in association with the ciliate epibiont Vorticella oceanica. The numerical abundance of V. oceanica was closely correlated to that of its host at certain depths. Potential food sources for V. oceanica in Otsuchi Bay were identified. Vorticella oceanica is redescribed following examination by light and scanning electron microscopy.

Infestation of harpacticoid copepods (crustacea) with ciliate protozoans

We report the first observations of ciliate epibionts on deep-sea, benthic harpacticoid copepods. One ciliate epibiont species belonged to class Karyorelictea, one to subclass Suctoria, and one to subclass Peritrichia. Our samples came from the continental rise off central California (36.709°N, 123.523°W, 3607 m depth). We found that adult harpacticoids carried ciliate epibionts significantly more frequently than did subadult copepodids. The reason for the pattern is unknown, but it may involve differences between adults and subadult copepodids in size or in time spent swimming. We also found that the ciliate epibiont species occurred unusually frequently on the adults of two species of harpacticoid copepod; a third harpacticoid species just failed the significance test. When we ranked the 57 harpacticoid species in our samples in order of abundance, three species identified were, as a group, significantly more abundant than expected by chance if one assumes that the abundance of the group and the presence of ciliate epibionts on them were uncorrelated. High abundance may be among the reasons a harpacticoid species carries a ciliate epibiont species disproportionately frequently. For the combinations of harpacticoid species and ciliate epibiont species identified, we found one in which males and females differed significantly in the proportion that carried epibionts. Such a sex bias has also been reported for shallow-water, calanoid copepods.