The Community Effects of Trematode Parasites on Species Interactions

Kailah Massey from the University of Georgia worked with Dr. Emlyn Resetarits.

Abstract Trematode parasites have a complex life cycle that infects and castrates snails as their initial host. (Wood et al., 2007). The snails our team observed were Elimia type snails. These snails have top-down control over algae in aquatic ecosystems. Snails have total control over algae and influence lower trophic organisms that feed on algae. Changes done by top-down organisms have an inverse effect on the lower trophic level organisms. High levels of parasite infections can alter the resilience of an ecosystem. Furthermore, research has shown that trematode parasites can influence host consumption, potentially creating more of a strain and impact on ecosystems (Rosemond et al., 1993). To assess this claim, we conducted location surveys to quantify infection prevalence within snails at each site. We then constructed a chlorophyll consumption trial consisting of a blind experiment to determine if infected snails consumed more algae on average than uninfected snails. Our results indicate that a trematode infection can increase the consumption of chlorophyll in their snail hosts. Trematode parasites were responsible for up to twenty percent of chlorophyll consumption across our sites. Further research will include the differences between visceral and gonadal infections on the consumption of Elimia snails.