Abstract

A study has been carried out in Kisangani during four months on the laying and the hatching rate of the snail of Achatina genus. Two hundred and forty adult snails were housed in cages of 9 m2 (14 snails per cage) and one collection cage of 18 m2 (60 snails). In the cacao litter lined cages (20 cm of width) in cacao plantation, the genitors were maintained to hatch eggs which were harvested once a week to be artificially incubated. Temperatures of the cacao-plantation and the litter have been controlled for this aim. The average weekly temperature under the cacao-plantation and in its litter was respectively 20.7°C and 22.5°C in the morning, 26.2°C and 23.5°C at mid-day and 23.3°C and 23.0°C in the evening. The average temperatures in different moments of the day have significantly differed between the cacao-plantation and its litter in morning hours and of mid-day and non-significantly at crepuscular hours. The average temperature of incubation has been of 22.9°C. The light genitors have produced more births than the heavy ones but with an inverse relationship with the numbers of eggs per birth and the relative fecundity, estimated to be 71% on average. The number of births has significantly differed with the genitor weight. The average rate of hatching was 75,3% with a significant difference according to genitor weights.


Keywords: Temperature, litter, laying, Achatina, hatching