PHENOTYPIC PLASTICITY IN AN ALIEN INVASIVE MUSSEL ACROSS A GRADIENT OF THEIR LIMITING FACTORS IN SOUTH AMERICA

ESTEBAN M. PAOLUCCI; MARCIA D. OLIVEIRA; PAULA SARDIÑA; FRANCISCO SYLVESTER; LEILA RON; LEONARDO MUTTI; MACISAAC, H. J

La Plata

Congreso; VI Congreso Argentino de Limnologia: Agua, ambiente y sociedad; 2014

Instituto de Limnologia "Dr. Raul A. Ringuelet" CONICET-CCT La Plata

Adaptation to new environments is an essential step in the establishment and spread of an alien species, and species traits such as phenotypic plasticity may be particularly important for survival in highly variable systems such as river floodplains. Limnoperna fortunei is a highly invasive, biofouling mussel native to Asia which, after being introduced into the Río de la Plata estuary around 1990, spread to almost the entire basin. We analyzed morphological variation in 19 introduced populations of the species distribution edge in the Paraguay and Uruguay rivers. We found differences between relative gill, palp area, and shell morphology of populations from geographically close sites but presenting divergent environmental conditions. Individuals from populations exposed to high chlorophyll and total suspended solids and low oxygen concentrations exhibited the most profound morphological variation. Differences in relative palp area were especially marked, and positively correlated with total suspended solids. L. fortunei`s morphological differences are likely associated with environmental variability in combination with developmental plasticity, as has been observed in other mussels. Phenotypic differences observed across a gradient of limiting factors suggests that developmental plasticity may be responsible for the species? survival and spread across unfavorable environments.