First microscopic evidence of invasive Ceratium furcoides ingestion by native Asplanchna sieboldii in a tropical reservoir, with a review of zooplankton predators of Ceratium

Biological invasions can impact food web interactions such as predator–prey dynamics, yet examples of native predators controlling non-native prey remain underexplored. Here, we investigate trophic relationships between Ceratium furcoides (Dinophyta) and plausible native zooplanktonic predators in a tropical reservoir. To our knowledge, this is the first visual documentation of C. furcoides ingestion by Asplanchna sieboldii in an invaded ecosystem. Our field data suggest opportunistic predation likely influenced by water level reductions and narrowing of the water column following an anomalous and well-documented drought period in southern Brazil. We recommend that future studies examine samples from other tropical and subtropical reservoirs to identify and report additional zooplankton associations with Ceratium and their specific environmental contexts, thereby supporting the development of potential biocontrol strategies.