First record of Orbopercularia lichtensteini (Peritrichia: Operculariidae) attached to a hemipteran, Corisella edulis (Nepomorpha: Corixidae), in Hidalgo, Mexico, with notes on its cytology and distributional patterns

Operculariidae includes sessile ciliate species mainly attached to diverse substrates, but records are scarce for their attachment to aquatic true bugs. The goal of this contribution is to provide new cytological data with optical and scanning electron microscopy of Orbopercularia lichtensteini, and some notes about their distribution on a Mexican corixid. We manually collected the corixids in a pond in Mexico during a six-month period, and all individuals were revised to observe the peritrichids. We calculated the abundance and prevalence, with an emphasis on the specific micro-location of the epibiotic peritrich on the host Corisella edulis. A total of 36,205 peritrichids were recorded in 158 corixids. The colonies with fine striated zooids were dichotomously branched and mostly attached to left eyes, but also on other body regions, i.e. left wings and rostrum. We conclude that some morphological colony traits bring some advantages for food particle capture, and aspects of the biology and morphology of Corisella edulis play an important role in determining the spatial distribution of O. lichtensteini.