Gregarines are a diverse group of protozoan parasites belonging to the phylum Apicomplexa. The parasites in this phylum are characterized by the apical complex which helps them penetrate organisms. Cryptosporidium is closely related to gregarines and can infect humans to cause illness. Gregarines exclusively infect invertebrates which makes them safe to handle. Studying the less harmful gregarines can provide information on parasites that are more dangerous to humans. Monocystis agilis, a specific type of gregarine, typically inhabits the seminal vesicles of earthworms that it infects. Earthworm populations and the number of parasites in invertebrates were both examined in this study. Earthworms were sampled across the city of Abbotsford, British Columbia, in different locations by using non-toxic substances. The earthworms were then dissected in order to isolate their seminal vesicle tissue and fluid. Microscopy allowed for counting the number of gregarines in dissected specimens. Using this data, the number of earthworms between three different types of locations (parks, farms, and gardens) was compared. The number of gregarines between native and invasive species of earthworms was analyzed. Microscopic photography allowed for detailed images of different stages of the lifecycle of Monocystis agilis to be visualized.
Results/Conclusions
Earthworm populations across different locations showed no significant differences (P > 0.05). Future studies can focus on analyzing elevation and soil depth which may provide further insight. Comparisons of the number of gregarines between native and invasive species of earthworms determined that there was a significant difference (P < 0.05). The results indicate that native and invasive species may interact with gregarines through unique methods. Invasive species could have developed mechanisms of resistance, allowing them to carry higher numbers of parasites. Alternatively, the discrepancy in the number of parasites could be attributed to other factors. Possible explanations may include that the smaller population of native earthworms had fewer contacts with the gregarines. This study showed that gregarines can be readily isolated from earthworm seminal vesicles. Both earthworms and gregarines open a multitude of possibilities for future research and expansion on current findings.