Egg predation and parasite prevalence in the invasive freshwater snail, Melanoides tuberculata (Müller, 1774) in a west Texas spring system

摘要

Melanoides tuberculata Müller, 1774 (Thiaridae), a freshwater prosobranch snail native to regions of Asia and Africa, was introduced into the U.S. in the 1960s and is now found in fifteen states. Melanoides tuberculata can affect native communities directly by displacing native snail species and indirectly by introducing foreign trematodes into novel environments. As the exact mechanisms of displacement of native snails by M. tuberculata are unknown, egg predation rates on native snails (Physella spp.) by two different size classes (>30 mm and <30 mm, total length) of M. tuberculata were determined in laboratory experiments. Additionally, M. tuberculata were sampled from Diamond Y Spring (Pecos County, TX) to determine if the exotic trematode Centrocestus formosanus (Nishigori, 1924) has been introduced into the system. No M. tuberculata > 30 mm were found to consume Physella spp. and only 2.8% of M. tuberculata snails consumed egg masses. None of the M. tuberculata collected from Diamond Y Spring were found to be infected with C. formosanus .