Microhabitat Differences in the Benthic Substrata Affect Parasitism in a Pulmonate Snail Host, Helisoma anceps

Abstract

The microhabitats in which hosts live can potentially influence the ability and success of parasites in finding and infecting these hosts. The infection dynamics of both digenetic trematode parasites and a nematode parasite (Daubaylia potomaca) infecting a pulmonate snail, Helisoma anceps , were observed in a small North Carolina lake using 3 different classifications of substratum type based on percent coverage by leaves and debris. There were no differences in snail site occupancy or density between substratum types, but small-scale differences in microhabitat impacted parasite prevalence and intensity in their gastropod hosts. Snails inhabiting substrata covered in more leaf litter and debris had a lower prevalence and intensity of infection by all of the trematode species and life stages when compared to H. anceps inhabiting other substrata types, while only the intensity of infection was impacted in D. potomaca infections. These findings emphasize the importance of microhabitat, specifically its physical components, in influencing parasite infection in intermediate hosts and that small-scale differences may significantly affect the patterns of infection.

Cercarial fauna of freshwater snails in selected agricultural areas in Laguna, Philippines

“…The differences in the cercarial prevalence among the three habitat types surveyed may be due to various possible reasons. Although environmental factors were not measured in this study, parameters such as water temperature (Studer and Poulin, 2013), pH (Candia et al, 2015), vegetation cover (Koprivnikar et al, 2007), and leaf litter (Luth et al, 2016) were found to influence snail community and trematode prevalence in an area. It is also important to note that the presence of other animals that may serve as final hosts for these trematodes may also be one reason for prevalence of infection.…”

The distribution of echinostome parasites in ponds and implications for larval anuran survival

“…The survey results demonstrated that infection in snails and amphibians differed among ponds, and that high prevalence in snails predictably corresponded to increased infection in larval green frogs. The enclosure experiment similarly showed that echinostome abundance in tadpoles differed among ponds and also among sites within ponds, with a non-significant trend of higher abundance in enclosures in structured microhabitats, likely due to higher snail densities in those areas or microhabitat variation in infection in snails (Sapp and Esch, 1994;Zimmermann et al 2016). Structured microhabitats are typically preferred by larval frogs, likely because of protection from some predators and higher resource levels (Warkentin, 1992;Tarr and Babbitt, 2002), but parasitism may introduce a potential cost.…”

Effects of Polyester Microplastic Fiber Contamination on Amphibian–Trematode Interactions

“…Alternatively, microplastics could act as a structural barrier to cercaria movement, increasing the time it takes cercariae to contact hosts. If microplastics were to delay cercariae from contacting hosts during their infective period, they could reduce cercarial transmission, as has been documented with other structural barriers (e.g., leaf litter; Zimmermann et al 2016). Given the diversity of host species that trematodes utilize (e.g., humans, fish, mammals, birds, gastropods, reptiles, and amphibians; Fried and Graczyk 2000), the commonality of free-living life stages across trematode species, and the energetic constraints facing them (Fried and Graczyk 1997), understanding the impact of microplastic contamination on trematode cercariae and their transmission to hosts has broad relevance to host-parasite dynamics.…”