The effect of slope direction and population density on water influx in a desert snail, Trochoidea seetzenii

Trochoidea seetzenii is widely distributed in the Negev Desert, dormant most of the year, and becoming active when sufficient moisture (dew or rain) is available. Its activity is then limited during the hours of the day when moisture is present. Unlike other desert snails, T. seetzeni generally aestivates above ground on bushes. The tritiated water dilution method underestimated total body water volume by 1.7% indicating that there was negligible exchange of tritium with non-aqueous hydrogen and underestimated measured water intake by 13.9%. Despite environmental differences between N- and S-facing slopes, T. seetzeeni had similar daily water influx on both slopes (54.8 μl and 51.4 μl per snail, respectively), suggesting that the snails were able to select microsites on both slopes in which the net effect on water influx was similar. There was interference among snails in searching for water and as a result water influx was density dependent. Daily water influx at a density of 10 snails m^-2 was 63.3 μl snail ^-1 and at a density of 50 snails m^-2 was 42.9 μl snail^-1. -from Authors