Assessing host competency between native and invasive snail species exposed to the native parasite Echinostoma revolutum

Christopher Glodosky,Gregory Sandland

doi:10.3391/ai.2014.9.1.07

Abstract

Invasive species have the ability to rapidly and extensively alter native ecosystems, and there is accumulating evidence to suggest that the introduction of invasive hosts can have influences on parasite transmission in native communities. In 2002, the aquatic snail Bithynia tentaculata was discovered in the Upper Mississippi River (UMR) where it now co-occurs with several native snails and their parasites. The goal of this study was to determine the competencies of a native snail (Physa gyrina) and an invasive snail (B. tentaculata) after controlled exposure to a native parasite species (Echinostoma revolutum). Results of our laboratory experiment indicated no difference in either the prevalence or intensity of infection between native and invasive snails, which was unexpected given past work on B. tentaculata. In addition, infection had no discernible influence on host life-history traits such as growth and survival. Together, these results may have a number of consequences for hosts and parasites within the UMR region. First, the presence of an additional competent host in the snail assemblage may reduce infection risk for native snail species through parasite dilution. Second, the occurrence of a competent invasive host may increase the transmission of E. revolutum to native definitive host species such as waterfowl and mammals. Ultimately, a better understanding of how native parasites cycle through the UMR snail assemblage could allow us to better predict: 1) transmission/invasion outcomes in the UMR and 2) the potential alterations that may occur in ecosystems at high risk of B. tentaculata invasion.

Highlights

Species introductions have profound impacts on global ecosystem dynamics leading to billions of dollars being spent on their control annually (Pimentel et al 2005)
While the exact mechanisms underlying the successful expansion of this species remain unknown, it is possible that interactions with native species, including parasites, may be modulating its success (Strayer 1999; Mills et al 2004; Sandland et al 2013)
Our study sought to assess the competency of B. tentaculata as a second-intermediate host for a common native trematode species (Echinostoma revolutum) found in native snails

Summary

Introduction

Species introductions have profound impacts on global ecosystem dynamics leading to billions of dollars being spent on their control annually (Pimentel et al 2005). Invasive species can spread rapidly within their new environments via natural and anthropogenic means (Frisch et al 2007; Meyerson and Mooney 2007). Studies have assessed the mechanisms underlying the dissemination of invaders from their points of origin, there is still very little known about the factors that facilitate invader success once these organisms arrive in new environments (Lodge et al 2006). This lack of knowledge hinders the application of control measures to mitigate the extent to which these organisms spread. This becomes even more important when invasive organisms serve as hosts for parasites within native habitats

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Conclusion