Meeting Abstract
P2.24 Monday, Jan. 5 Living on the edge: A field study on the effect of salinity and parasitism on an intertidal gastropod LONGORIA, A*; AGUIERRE, P; FREDENSBORG, BL; University of Texas_Pan American; University of Texas_Pan American; University of Texas_Pan American blfredenbor@utpa.edu
Physiological stress and parasitism are both important stressors affecting the abundance, diversity and composition of intertidal animal communities. However, rarely have the two stressors been studied in concert. This study investigated the effect of a naturally occurring rapid decrease in salinity on the density of plicate horn snails, Cerithidea pliculosa, and the prevalence (%) of larval trematodes (flukes) using the snails as hosts. Random collections of C. pliculosa were conducted on two separate occasions on three intertidal flats in Laguna Madre, South Texas. The density of snails was determined and >100 snails were dissected per site to determine the infection status of the snails. The first collection was conducted five days prior to the arrival of a category two hurricane (Hurricane Dolly). The second sampling event took place three weeks later. A drop in salinity was recorded in the study area due to substantial rainfall during the storm. No difference in the density of snails was observed for any of the three sites indicating that C. pliculosa is tolerant to variations in salinity. In one of the three sites, the prevalence of infection by larval trematodes decreased significantly(P = 0.012)suggesting that infected snails disproportionately were lost from the population. No difference in prevalence could be detected for any of the two other sites (P= 0.10 and P = 0.99),but the proportions of trematode species significantly differed between the two sampling events for all three snail populations (p <0.025). In conclusion, occasional events of stressful conditions can influence host-parasite interactions but the outcome seems to be species specific. More studies are needed on the effect of physiological stress on host-parasite interactions.
