INVASION OF Corbicula spp. IN ARGENTINA: PHENOTYPIC PLASTICITY OF A GLOBAL INVASIVE BIVALVE

PAOLUCCI, ESTEBAN; HUNICKEN, LEANDRO; SYLVESTER F

Buenos Aires

Congreso; Marine and Freshwater Invasive Species: Ecology, Impact and Management; 2016

CONICET & Aquatic Ecosystem Health and Management Society

Invasive freshwater bivalves are a group of special concern because of their rapid expansion and wide range of effects. Freshwater clams in the genus Corbicula, native to Southeast Asia, began to expand globally in the early last century. In Argentina, the genus was introduced through Río de la Plata in the 1970s, and 50 years later has achieved a countrywide distribution across a diversity of aquatic habitats. An important adaptation mechanism is phenotypic plasticity. Changes in the morphology of the shell, gills, and labial palps have been reported for other invasive bivalves such as the golden mussel as a response to new environmental conditions in habitats colonised. In this study, we compare the morphology of six invasive Corbicula populations across the provinces of Salta, Córdoba, Catamarca, Buenos Aires and Río Negro in Argentina. We used 20 individuals per site to calculate gill area/valve area (GV); palp area/valve area (PV); and palp area/gill area (PG) ratios for these populations. We conducted analyses of covariance to examine differences between these morphometric relationships, using clam size (surrogate for age) as a covariate. All ratios showed significant differences among populations (GV: F(5,121) = 12.05, PV: F(5,108) = 12.72, p PG: F(5,108) = 15.00; p <0.001). Population of Dique Cabra Corral, a highly modified reservoir in Salta, showed the highest palp/gill area ratio, while Biallet Massé, a pristine stream in Córdoba, was in the other extreme. These results illustrate Corbicula´s phenotypic plasticity, and suggest this feature may be instrumental to its adaptation to new environmental conditions. Extension of our study to more populations and detailed consideration of ambient data will improve our understanding of the role of phenotypic plasticity to subsidise Corbicula´s invasive success.