Investigating the Sublethal Effects of Cannabis sativa on Earthworms and Trematode Cercariae

Abstract

<p>Rising demand for <em>Cannabis sativa</em> production and use has resulted in recent rapid widespread legalization and large-scale production. Due to its abundance and variety of unique secondary metabolites, <em>C. sativa</em> cultivation could pose a risk to natural terrestrial and aquatic environments. Currently, its general effects on invertebrate animals are not well studied beyond lethality. Here, I investigated how ingestion of <em>C. sativa</em> plant material affected the growth, mortality, and behaviour of an earthworm species. Earthworms that fed on <em>C. sativa</em> gained less weight and took longer to escape from an external heat stimulus. However, mortality and escape behaviour from an external light stimulus were not affected. I also investigated if exposure to aqueous cannabinoids affected the activity and longevity of free-swimming infectious cercariae of trematode (flatworm) parasites. Neither high nor low concentrations of cannabinoid solutions had any effects. Exposure to <em>C. sativa</em> could thus have some effects on non-target organisms.</p>