Reproductive pattern of the aggressive invader Limnoperna fortunei (Bivalvia, Mytilidae) in South America

Abstract

Limnoperna fortunei is an aggressive freshwater invader species recorded for the first time in 1991 at Balneario Bagliardi, Río de la Plata Estuary, Argentina. Since then it has spread rapidly within South America. We tested the hypothesis that invasive species need a time span for the development of a reproductive pattern once settled in a new environment. We analyzed the reproductive cycle of a population of L. fortunei from Guaiba Lake (29°55′S; Rio Grande do Sul, Brazil) and compared it with previous studies at Balneario Bagliardi (34°52′S). We studied 834 specimens from Guaiba, following routine histological techniques. At any sampled period, the highest proportion of specimens were mature and gonads showed no resting periods. Female gonad maturation periods and oocyte growth were recorded throughout the year. Five periods of spawning of different intensity were differentiated. The reproductive pattern of the Guaiba population showed more spawning events and a remarkable recovery capacity of the female gonad compared to the Balneario Bagliardi population. The reproductive patterns of L. fortunei from Guaiba two years after invasion shows similarities with the reproductive pattern described previously from Balneario Bagliardi after two and three years of invasion