Abstract

A study to investigate the factors affecting hatchability of Archachatina marginata eggs, had 600 eggs collected from snail pens and incubated in treated substrates; moist soil/sawdust mixture (MSD), moist sawdust (MD), moist soil (MSb), dry sawdust (DD) and dry soil (DS) as well as in rearing pens (1 m × 1 m × 0.8 m) containing moist soil (MSp). Results showed that snail egg weights  at  laying  ranged  from  250  to  1100  mg  (mean  of  670±247  mg).  Egg lengths and widths ranged from 13.0 to 16.00 mm (mean of 14.88±0.94 mm) and 9.00 - 11.00 mm (mean of 10.80±1.02 mm) respectively. Snail egg hatchability in MSD and MD of 64.0±4.8 and 61.5±3.9%, respectively were better (p<0.05) than in MSp (50.5±4.4%) and MSb (45.5±3.5%) among media in which eggs hatched. Dry Incubation media (DS and DD) had 0% hatchability. Best hatchability was between 50 and 70% humidity.  Embryonic  mortality  showed  a  reverse  trend  with  MSD (36.0±4.8%) and MD (38.5±3.9%) recording significantly  lower (p<0.05) values than MSp (49.5±4.4%) and MSb (54.5±3.5%). Incubation temperature ranged from 17 to 20°C and Incubation duration ranging from 22 to 35 days. Correlated analysis revealed a weak significantly (p<0.05) positive relationship (r=0.097) between egg weight and hatchability and a negative relationship (r=-0.234) between egg weight and embryonic mortality. Therefore, snail eggs could be incubated in moist sawdust and moist soil/sawdust mixture with humidity from 50 to 80%, at temperatures ranging from 17 to 20°C and that snail eggs with higher weights are most recommended for incubation.

Key words: Temperature, humidity, hatchability, embryonic mortality, Archachatina marginata eggs.