Abstract: Mucus trails of gastropods on copper sheets placed on the inner wall of terrariums give information about stress in snail populations. From the exponential regression curve y=Ae^–Bx (y = number of trails, x = trail height on the sheet) we calculated the estimates x50, xl0 and x5 at which respectively 50, 10 and 5 trails were attained. These values reported on vertical line segments made it possible to compare the antagonistic behaviour between species as a function of population densities or other disturbing factors. The method was tested on 4 Zonitidae species: Zonitoides nitidus, Z. arboreus, Oxychilus draparnaudi and O. cellarius. In the light of these results we discussed the measure of inter and intraspecific disturbance in molluscan populations and the impact of the disturbance on the predation capacity of the snails.