Niche Restriction and Host Gut Bacterial Sensitivity in Intestinal Nematodes of the African Nightcrawler

Niche restriction is observed in tandem with the life history traits of parasites, reflecting their response to changing host conditions. Mesidionema praecomasculatis predominantly inhabits the anterior intestine of the host earthworm African nightcrawler, whereas Thelastoma endoscolicum, a pinworm, resides in the hindgut, which is characterized by a higher population of resident bacteria. Control experiments indicate that both intestinal nematodes are sensitive to environmental residues of the anthelmintic mebendazole. However, reductions in T. endoscolicum infection were observed only after host exposure to food limitation or the antibiotic streptomycin, both of which also reduced gut bacterial abundance. These findings underscore the strong correlation between T. endoscolicum infection dynamics and the host's bacterial abundance, aligning with previous research on the potential relationship between pinworms, host digestion, and the resident bacterial population. Given that African nightcrawler is a widely used compost earthworm, the influence of intestinal nematodes, along with varying prevalence under different farming conditions, may significantly affect the efficiency of earthworm composting-an aspect that has been relatively underexplored in the composting industry.