Epizoans on a tropical freshwater crustacean assemblage

Abstract

Prevalence and substrate specificity of epizoans on crustacean zooplankton were examined during an annual cycle in Tulé Reservoir, a large, shallow and polymictic waterbody in western Venezuela. Epistylis sp., a ciliate protozoan, and Synedra sp., a pennate diatom, were the most frequent epibiont taxa. The prevalence of all epibionts on 1800 individual crustaceans was only 3.3%, and the occurrence of the two epibiotic taxa together on the same substrate zooplankter was low (3.3% of total infested crustaceans). Cyclopoid copepods were preferred as substrate for Epistylis sp. Neither epibiont taxon was found on copepodids or adults of a calanoid. Both epibionts were absent in the early rainy season but appeared in mid rainy season and showed the highest prevalence in the early dry season. During the remainder of the dry season prevalence was low. Epibiont prevalence was not related to presence or absence of zooplankton taxa or water temperature. Differences from temperate epibiont communities are discussed Resumen. A lo largo de un ciclo anual, se estudió la prevalencia y la especificidad al sustrato de los epibiontes de la comunidad de crustáceos planctónicos del Embalse Tulé, un cuerpo de agua somero y polimictico del Occidente de Venezuela. Epistylis sp., un protozoario ciliado, y Synedra sp., una diatomea pennada, fueron los taxones más frecuentes. La prevalencia de ambos epibiontes en conjunto sobre los 1.800 individuos examinados fue de 3,3% y la presencia de ambos epibiontes en el mismo sustrato fue baja (3,3% del total de individuos infestados). Los copépodos ciclopoideos fueron preferidos por Epistylis como sustrato. Ningún epibionte se observó en los copépodos calanoides. Los epibiontes aparecieron a mediados del período de lluvias y alcanzaron su máxima prevalencia al principio del período de sequía. La prevalencia no se encontró relacionada ni con la presencia o ausencia de las especies zooplanctónicas ni con la temperatura del agua. En el presente trabajo se realizan comparaciones con las comunidades epibiónticas de la zona templada y se discuten explicaciones a las diferencias encontradas.

Spatial and temporal occurrence of Rhabdostyla cf. chironomi Kahl, 1933 (Ciliophora, Peritrichia) as an epibiont on chironomid larvae in a lotic system in the neotropics

“…3 Mean values of bacterial density and infestation prevalence of Rhabdostyla cf. chironomi in the five sampling stations (S1, S2, S3, S4, and S5) in São Pedro Stream However, some studies have failed to demonstrate a strong relationship between epibiont infestation prevalence and host abundance (López et al 1998;Hanamura, 2000;Utz & Coats, 2005). In this study, we observed a positive correlation between host abundance and infestation by R. cf.…”

A checklist of epibiotic ciliates (Peritrichia and Suctoria) on the cladoceran crustaceans

“…López et al (1998) studied epibiotic ciliates on the Cladocera inhabiting a large reservoir in Venezuela. In majority cases, they found that only one species of ciliate was present on a single cladoceran species.…”

Growth of the peritrich epibiont Zoothamnium intermedium Precht, 1935 (Ciliophora, Peritrichia) estimated from laboratory experiments

“…Peritrich ciliates commonly colonize planktonic crustacea (Hermann and Mihursky, 1964;Green, 1974;Henebry and Ridgeway, 1979;López et al, 1998), with the majority of the reports on this epibiotic relationship focusing on the effects of these epibionts on host survivorship and reproduction (Kankaala and Eloranta, 1987;Xu and Burns, 1991;Xu, 1992;Weissman et al, 1993). However, studies emphasizing aspects of the peritrich life cycle such as growth rates of these ciliates are still lacking.…”