High tolerance to abiotic stressors and invasion success of the slow growing freshwater snail, Melanoides tuberculatus

Considerable research has been conducted to determine traits common to invasive species with the goal of predicting, preventing, or managing invasions. The importance of physiological tolerance to abiotic stressors in the ability of invasive species to establish and displace native species has been hypothesized to be important although there are few actual tests of the hypothesis in the literature. In freshwater molluscs it has been suggested that high fecundity is the most important trait for invasion success and that physiological tolerance to abiotic conditions is unlikely to play a significant role. We examined the tolerance to abiotic stressors using a known invasive snail species (Melanoides tuberculatus) that has a much slower growth rate and fecundity than a native species it has displaced (Biomphalaria glabrata). We tested the hypothesis that M. tuberculatus would have significantly greater tolerance to natural and anthropogenic abiotic stressors (cadmium, malathion, temperature extremes, and desiccation) which may provide a mechanism for displacement of B. glabrata. A time-to-event analysis was used to determine relative tolerance between species. M. tuberculatus was significantly more tolerant to the tested abiotic stressors than B. glabrata with the exception of low temperature (5°C). Stress tolerance may partly explain the ability of M. tuberculatus to displace B. glabrata despite having a much lower growth rate and fecundity. These results also suggest that M. tuberculatus is likely to have a strong advantage in disturbed or polluted habitats. Identifying those traits most important for the invasion success of particular species could be used to better inform removal strategies and may allow for improved predictions of invasion potential.