Abstract

A study has been carried out in Kisangani during four months on the laying and the rate of eclosion of snail of the genre of Achatina. Two hundred and forty adult snails were loged in the cages of 9m2 (14 subjects per cage) and one cage of collection of 18m2 (60 subjects). In the tapissed cages of litter of cacao-plantation (20 cm of width), the genitors were entertained to give the eggs which were recolted one per week to be incubed artificially. The temperatures of the cacao-plantation and the litter have been controlled for this aim. The obtained results indicate that 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 in mid-day and 23,3°C and 23,0°C in the evening. 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 temperature of incubation has been of 22,9°C. The light genitors have produced more births than the heavy genitors with an inverse speed for the numbers of eggs per birth and the relative fecundity which has been estimated to 71% in medium. The number of births has significantly differed in function of medium vif weigh of genitor. The average rate of eclosion has been evaluated to 75,3% and has also revealed a significant difference according to weight of genitor.


Key words: Achatina, African giant snail, temperature, litter, laying, eclosion