Life on the beach for a sand crab (Emerita rathbunae) (Decapoda, Hippidae): parasite-inducided mortality of females in populations of the Pacific sand crab caused by Microphallus nicolli (Microphallidae)

Abstract

Parasites, by definition, can affect mortality of their host, making parasitism an important biotic determinant of animal population dynamics and community structure. Reduction in the number of larger, reproductive age females in populations of the Pacific sand crab, Emerita rathbunae (Decapoda, Hippidae), was observed in studies of the helminth community of this host. The aim of this study was to determine if high abundance of the metacercaria of the trematode, Microphallus nicolli (Microphallidae), causes mortality in this host. Females of E. rathbunae were collected from four sandy beaches in Guerrero State, Mexico, and helminths were collected from each crab. An analysis of variance (Anova) was applied to these data in order to identify differences in abundance between sizes of crabs, and an analysis of covariance (Ancova) was applied to identify differences in the abundance of metacercariae between locations