Constitutive and adaptive changes of giant african land snails, Archachatina marginata and Achatina achatina, to support transition from the aestivating state to arousal
By OMOYAKHI, J.M. AND OSINOWO, O.A.
The morphological alterations through aestivation to arousal and subsequent changes were determined in giant African land snails, A. marginata and A. achatina. The snails were induced to enter into and sustained in aestivating state for 6 weeks. The control group was sacrificed while others were aroused and fed for 2, 4 and 6 weeks before sacrificed. During the 6 weeks of aestivation preceding the post-aestivation (arousal), there was a mean liveweight reduction of 59.7 % of initial liveweight of A. marginata and 60.4 % of A. achatina. Hydration and feeding provoked a new increase in liveweight by 192.6 % and 160.3 % of the liveweight within two weeks for A. marginata and A. achatina respectively. While A. marginata regain its lost weight within 2 weeks, A. achatina recovered only about 76.13 % which was significantly lower (P < 0.01) than the 72.67 ± 7.41 g weight loss over the 6 weeks aestivation period. In both species, shell weight markedly increased during the first 2 weeks of arousal, tending to stabilize thereafter. The haemolymph significantly increased (P < 0.001) with weeks of post-aestivation rising to 384.8, 427.1 and 335.1 % of aestivated haemolymph for A. marginata and to 180.7, 223.1 and 221.9 % for A. achatina by 2, 4 and 6 weeks respectively. The study concludes that the growth changes during and after aestivation are basically the result of the dynamics of the haemolymph and body moisture.
Keywords: Morphology, alteration, aestivation, hydration, transition, snail
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