Influence of substrate humidity on desiccation resistance capacity in Subulina octona (Mollusca, Subulinidae)

Abstract

The aim of this study was to verify the influence of substrate humidity on desiccation resistance of Subulina octona, continuously exposed, for 48 h, to the temperature of 35°C. Forty individuals conditioned in 2 plastic boxes, one box containing black earth humidified with 40 ml water and the other one containing dry black earth were used. The retraction of cephalopodal mass inside the shell and the number of dead individuals was evaluated. Snails from dry and humid substrate boxes showed cephalopodal mass retraction of 9.9 cm±2.88 and 2.78 cm±3.17, respectively, after 12 h of exposure; 8.55 cm±1.3 and 6.33 cm±2.91, after 24 h; 11.07 cm±4.19 and 7.27 cm±2.7, after 36 h, 9.12 cm±2.15 and 6.47 cm±2.11, after 48 h. Every individual of dry substrate box died whereas every individual of humid substrate box survived. These results showed that substrate humidity was an influent factor regarding desiccation resistance in S. octona.