Meeting Abstract
Parasites are known to affect the life history of their hosts, including lifespan, fecundity, and maternal investment in offspring. Previous work on freshwater snails has shown that trematode infections reduce host fecundity and survival. In this experiment, we considered a novel snail-acanthocephalan system and compared the effects of acanthocephalan and trematode infection on host survival and fecundity. To do this, we measured life history traits of 36 field caught Helisoma sp. snails in the lab, including their survival, egg production, and size. After the snails died, they were dissected and examined for acanthocephalans and trematodes. To determine if there were potential hereditable differences between snails infected and not infected with acanthocephalans, we raised the offspring of the wild caught snails in the lab and measured their egg production and size. We found no significant difference in egg production, size, or survival between snails infected and uninfected with acanthocephalans. However, snails with trematodes laid fewer eggs, were larger, and had lower survival than uninfected snails. The offspring of snails infected with acanthocephalans did not differ in size or egg production from the offspring of uninfected snails. Trematode and acanthocephalan infections were not independent; the majority of snails were co-infected or uninfected. These results suggest that acanthocephalans do not reduce snail fecundity or survival, while trematodes do. High co-infection rates could suggest that acanthocephalans and trematodes are encountered together in the field, older snails have a high probability of encountering both parasites during their life, or that infection with one parasite increases the susceptibility to other parasites.
