Exploring the desiccation tolerance of the invasive bivalve Corbicula fluminea (Müller 1774) at different temperatures

2020-05-27T13:46:53Z (GMT) by Simone Guareschi Paul Wood
Corbicula fluminea (Müller, 1774) (Mollusca, Corbiculidae) is among the most successful and widespread invaders of aquatic ecosystems worldwide. Given its wide geographical distribution and documented effects on aquatic ecosystems, there is considerable interest in quantifying its behaviour, propagation and control. We conducted a series of laboratory experiments to assess the effects of complete desiccation (aerial exposure at high relative humidity) on a UK population of C. fluminea for: (1) different environmental temperatures (6 scenarios: from cool winter droughts to summer heatwave thermal conditions); and (2) two size classes (> 1 cm and ≤ 1 cm). A mortality rate of 100% was obtained for all experiments, except the lowest temperature scenario of 4 °C. For both high-temperature scenarios (25 and 30 °C) 100% mortality was recorded after 48 h, and an elevated mortality rate recorded after 24 h. An extended period of desiccation of 5–6 days would be necessary to reach a mortality rate of 90% at 15 °C and 3.5 days at 20 °C. Statistical analysis demonstrated a significant effect of temperature on mortality, but both size classes displayed similar responses to desiccation. The greatest difference in mortality was recorded between the highest and lowest experimental temperatures. C. fluminea was particularly tolerant to desiccation when low temperature and high humidity conditions coincided, suggesting it could potentially spread to regions beyond its current eco-geographical range. The results will be of direct interest for regulatory authorities considering desiccation (and water level management) as a means of managing and preventing the further spread of this species.