First observation of potential phoresy between Planorbarius metidjensis and Ancylus fluviatilis (Gastropoda: Planorbidae) in Algeria

Phoresy, an ecological phenomenon in which one organism attaches itself to another for dispersal, has been observed in various species. In this study, we describe the potential occurrence of phoresy between Ancylus fluviatilis and Planorbarius metidjensis in Algerian freshwater. Through field observations, we provide evidence to suggest that P. metidjensis may serve as a transport host for A. fluviatilis, facilitating its movement within aquatic ecosystems. Additionally, juvenile P. metidjensis were observed attached to adults of the same species, which may be a case of intraspecific phoresy. This interaction has implications for understanding the ecology and dispersal mechanisms of freshwater molluscs.