ScienceAsia 12 (1986): 023-030 |doi: 10.2306/scienceasia1513-1874.1986.12.023

EFFECTS OF SOME PHYSICO-CHEMICAL FACTORS ON THE HATCHING OF EGG MASSES AND ON THE SURVIVAL OF JUVENILE AND ADULT SNAILS OF BULINUS (PHYSOPSIS) ABYSSINICUS

MOHAMED A. DAGAL, E. SUCHART UPATHAM, MALEEYA KRUATRACHUE and VITHOON VIYANANT

ABSTRACT: Effects of some physioo-chemical factors-salinity. water temperature and hydrogen ion concentration-on the hatching of eggs and on the survival of juvenile and adult snails of Bulinus (Physopsis) abyssinicus were studied. All factors were found to affect the hatchability of egg masses and the survival of juvenile and adult snails. As the concentrations of sodium chloride solutions increased. the rates of hatching of egg masses and the survival rates of juvenile and adult snails. decreased. The optimum temperatures for the hatchability of egg masses and the survival of snails were between 25^o-30^o C. respectively. The best pH at which the egg masses could hatch and the snails could survive well was 7.5. Below pH 6. and above pH 8. no eggs hatched and none of the snails survived.

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Center for Applied Malacology and Entomology. Department of Biology. Faculty of Science. Mahidol University, Bangkok. Thailand

Received 28 November 1985