The substratum moisture at the beginning of the bioassay wascalculated by weighing cubes or leaf litter (n = 3) with no animals(made with remaining material of the bioassay) before and after≥48 h in the oven at 60◦C (leaf litter) and at 105◦C (sedimentand clay). During the bioassay substratum moisture was calculated using three samples of each material of the bioassay. Additionally,to characterize the inside conditions of polyester bags, air temper-ature (◦C) and relative humidity (%) was recorded every hour bymeans of a Data Logger (Log32) which was daily moved to a dif-ferent bag. Mean shell length of the experimental snail population(n = 148) was 3.42 ± 0.3 mm.