Survival and biophysical changes of three common species of land snails in Edo and Delta States during a 12-week aestivation
The experiment was conducted to determine the changes in the biophysical parameters during starvation in three common species of land snails identified in Edo and Delta States. A total of 252 matured healthy snails comprising three species (Archachatina marginata, Archachatina papyracae and Achatina fulica) were used. A completely randomized design was used in a 3 x 4 factorial arrangement. At the end of two weeks acclimation period, feed and water were withdrawn for 4, 8 and 12 weeks. Result shows that A. marginata has significantly (P<0.05) highest initial liveweight. A. papyracae had the least weight but was not significantly (P>0.05) different from the weight of A. fulica used in the study. During the 12 weeks of starvation, A. papyracae recorded the highest mortality rate of 24.58 %. A. marginata and A. fulica respectively recorded mortality rate of 9.05 and 6.52 %. A. marginata reflected two stages of major weight decline; 2nd and 9th weeks. The A. papyracae and A. fulica however declined conspicuously only at the 1st week. The weight of the muscular foot which constitutes the edible portion of the three species decreased between 0, 4 and 8 weeks. There were no significant differences in weight in each of the three species. Twelve weeks aestivation eventually resulted in further and significant weight loss. The aestivation lengths did not affect the shell weight in the three species, except A. marginata with significant decline at the 12th week. This study indicates that A. marginata and A. fulica are bigger in size and more tolerant to extended starvation than A. papyracae.
Keywords: Biophysical, aestivation, Archachatina marginata, Archachatina papyracae, Achatina fulica