Liveweight Changes and Reproductive Performance of Snails (Archachatina Marginata) Under Controlled and Naturally Induced Aestivation

The liveweight changes and reproductive performance of snails (Archachatina marginata) under controlled (watered throughout the experimental period, aestivated for 6 and 12 weeks) and naturally induced aestivation were investigated. Eighty (80) reproductively matured snails with five snails replicated four times in a completely randomized design were used. Liveweight and mortality were monitored during aestivation. Eggs collected were incubated. While the continuous watered group (0A) gained 11.95 g, the groups aestivated for 6 weeks (6A), 12 weeks (12A) and by nature (N) respectively recorded -40.05, -88.28 and -51.29 g. Mortality records showed 1, 1, 2 and 0. Apart from clutch size and number of snailet hatched, the investigated reproductive indices reflected significant (P<0.05) differences. The average clutch number was highest in 0A (5.65) followed by 12A (4.25), 6A (2.80) and N (2.67). Clutch weight was highest in N (25.17 g) which differ statistically from 0A (21.54). This was however not significantly different from 6A (22.88g) and 12A (24.32g). These respectively gave an average egg weight of 2.92, 2.91, 3.16 and 3.21 g for 0A, 6A, 12A and N. Hatchability was significantly highest in 6A (95.92%) which was not significantly different from 12A (93.69 %) and N (89.48 %). The later however, did not differ statistically from 0A. 0A nevertheless gave the highest snailet weight (2.63 g) and the least was recorded from 6A (1.53 g). It is evident from this study that aestivation although depressed weight and overall number of eggs laid, it however favoured hatchability and incubation period in A. marginata.