The background for the present investigation was our maintenance of cultures of M. macrocopa for stress ecology studies, in which we aimed to determine whether the heritage of cross tolerance was epigenetically controlled and based on DNA methylation in the presence of humic substances. To pursue this, in xenobiotic experiments, we pre-exposed Moina to humic substances, and then tested their cross tolerance against sea salt (following Suhett et al. (2011)). During these xenobiotic experiments, some cultures became infected with flagellates, allowing us the opportunity to study them, and their response to DOC and salt.