Comparative assessment of occurrence of Monocystis sp. in wild and cultured varieties of Lumbricus terrestris (Linnaeus, 1758)

Abstract India, known for its strong agrarian economy, faces significant environmental issues, for which earthworms might offer a feasible solution. The protist Monocystis, a unicellular parasite that forms spores, resides in the seminal vesicles of all earthworm species and is associated with parasitic infections that can result in castration. Therefore, the presence of Monocystis raises major concerns. This group of gregarine parasites, a member of Apicomplexa phylum, lives in the seminal vesicles of earthworms and feeds on their sperm.The aim of this research is to assess the prevalence of Monocystis infection across various types of earthworms, with a particular focus on comparing wild and cultured specimens. Earthworms were collected from both natural habitats and cultured environments from reputable sources, and their seminal vesicles were subsequently excised. These samples were then teased in normal saline and examined under a microscope. This study suggests that wild-type earthworms show a considerably greater vulnerability to Monocystis infections than their cultured relatives, supporting earlier claims that "all earthworm species are infected by Monocystis." The current study provides the initial definitive microscopic documentation of the presence of Monocystis sp. in wild populations of Lumbricus terrestris, potentially identifying it as Monocystis lumbrici, but further analysis is needed to confirm this.