Reproductive success of inbred strain MV31 of the ctenophore Mnemiopsis leidyi in a self-sustaining inland laboratory culture system

Ctenophores are an attractive lineage for studying animal evolution due to their early divergence from other metazoans. Among Ctenophora, Mnemiopsis leidyi is a model system for developmental, cellular, molecular genetic, and evolutionary studies. Until recently, many of these studies were conducted on wild-caught animals, limiting access to researchers on the coast. Here we present significant advancements towards culturing M. leidyi in laboratories without coastal access, enabling its wider use as an experimental and genetic model system. We detail updated feeding regimes that take advantage of co-culturing Brachionus rotifers with Apocyclops copepods, and quantify the reproductive output of our M. leidyi lab strain on this diet. Our updated feeding regime maintains reproductive fitness comparable to wild-caught individuals. Importantly, we have eliminated the logistical complexities and costs of regularly feeding live larval fish to M. leidyi. Our updated protocols make it feasible to maintain continuous ctenophore cultures independent of access to both coastal populations of wild M. leidyi and larval fish culturing facilities.