Cold tolerance varies among invasive populations of the Asian clam (Corbicula fluminea)

Abstract

The distribution of the subtropical Asian clam Corbicula fluminea (Müller, 1774), one of the world’s most invasive freshwater molluscs, is reportedly constrained by a lower thermal tolerance limit of 2°C. Although its occurrence in north temperate regions is typically restricted to artificially heated waterbodies, the species has been found to overwinter in unheated lakes and rivers. In laboratory experiments, we compared the cold tolerance of populations from several geographically distinct sites spanning 35°N to 46°N in eastern North America. Each population contained individuals that fully recovered from two months of continuous exposure to near freezing (1°C) conditions, contrary to published accounts of C. fluminea’s thermal ecology. Survivorship increased with body size and was enhanced by prior acclimation to a low temperature (10°C) compared to a higher one (18°C). When acclimated to 10°C, clams from northern populations exhibited greater survivorship (55.0 ± 16.1%) than those from southern populations (26.7 ± 19.2%). However, one southern population demonstrated survivorship as great as that of the most tolerant northern population, suggesting that its clams could overwinter in unheated northern waterbodies. Differences among populations indicate either that contemporary evolution has occurred or that developmental plasticity shapes future acclimation responses.

Overwinter survival of Corbicula fluminea in a central Minnesota lake

“…observations by Cvetanovska et al [41] which documented a lag period from exposure to cold temperatures and clam mortality such that survivorship remained high immediately following 8 weeks of exposure to cold temperatures but a significant drop in survivorship was observed after 8 weeks in recovery during lab trials. Our winter size class analysis indicates there were already at least two size classes present in Briggs Lake during the 2020-2021 winter season.…”

“…We speculate that the overwinter survival and apparent reproduction in these two central Minnesota lakes are evidence of the evolution of increased cold tolerance at the northern invasion front of C. fluminea. Laboratory trials by Cvetanovska, et al [41] indicated that C. fluminea from colder climates were more likely to tolerate exposure to temperatures near freezing temperatures with acclimation than individuals collected from warmer climates. Evolution of cold tolerance at invasion fronts have been observed in other invasive species including an invasive house gecko (Hemidactylus frenatus; [57]), cane toads (Rhinella marina; [58]), elongate hemlock scale (Fiorinia externa; [59]), and mosquitofish (Gambusia affinis; [60]) and lab experiments have demonstrated the ability of another invasive mollusc, the apple snail (Pomacea canaliculata) to develop improved cold tolerance with acclimation [61,62].…”