Adaptive changes in growth and morphological composition of aestivating giant African land snails, Archachatina marginata and Achatina achatina

Abstract

The experiment investigated the changes in liveweight and body composition at 0 (control), 2, 4 and 6 weeks of aestivation using 40 snails. The  experiment was conducted in a completely randomized design laid out in a species x weeks factorial arrangement. The results showed that though both species had identical initial  liveweights, the overall average weight after 6 weeks of aestivation was significantly higher (P < 0.05) for A. marginata (138.31 ± 5.47 g) than for A. achatina (118.81 ± 6.61 g). In both species, liveweight declined significantly (P < 0.001) with weeks of aestivation to 88.7, 83.1 and 52.4% of initial liveweight for A. marginata and 82.1, 62.8 and 35.0% for A. achatina during 2, 4 and 6 weeks respectively. There were declines in shell weight (P < 0.05), soft body weight (P < 0.05), dry weight (P < 0.01), haemolymph (P < 0.01) and body moisture (P < 0.001) for both species over the 6 weeks of aestivation. The species effect was more pronounced in A. achatina than in A. marginata