Reproductive pattern and sexual system of the nocturnal seagrass shrimp Ambidexter symmetricus (Decapoda: Caridea: Processidae) in a Florida bay

Abstract

The purpose of the current study was to analyse the reproductive ecology and sexual system in Ambidexter symmetricus (Processidae), a nocturnal seagrass shrimp. This work was conducted in St Joseph Bay, Florida, in May–August 2010 and April–October 2011. The sex ratio in A. symmetricus and the presence of juvenile females supported the hypothesis of a gonochoric sexual system. Breeding in the population occurred seasonally from April until September. Successive spawning of individual females was shown by the presence of late-stage (prespawning) ovaries in females that were brooding late-stage (near hatching) embryos. Female A. symmetricus were generally larger and more abundant than males. Male A. symmetricus with parasites exhibited gigantism. Because of seasonal differences in recruitment and growth, body size varied with time of year, with larger (overwintered) individuals collected in April and May, and smaller more recently recruited individuals more abundant in September and October. The population biology of this species is similar to many other warm-temperate, shallow-water carideans, thus supporting hypotheses about latitudinal variation in breeding and recruitment in marine benthic invertebrates.