MORPHOMETRIC STUDY OF THE REPRODUCTIVE SYSTEM OF GIANT AFRICAN LAND SNAIL Archachatina marginata ovum (Pfeiffer) (Pulmonata: Achatinidae) FOUND IN ILE-IFE, SOUTHWESTERN NIGERIA.

Abstract

The morphometry of the reproductive organs of the giant African land snail, Archachatina marginata ovum from wild collection at Ile-Ife, southwest Nigeria, was assessed during March - May (early rainy season) and August – October (late rainy season) of 2010. A total 134 snails were dissected and clas-sified into one of five different reproductive states (low mating readiness; high mating readiness; egg production; gravid and post reproductive). The five states were observed in snails collected during the early rainy season, whereas the gravid state was not observed in the collections during late rainy sea-son. Albumen gland was considerably enlarged at egg production state forming about 60 % of the total weight of the reproductive system, while vas deferens was significantly longer in snails at high mating readiness state. The sizes of the reproductive organs were not substantially related to the size of the snail as the coefficient of determination (r2) of the relationship were in most cases below 0.5. The over-all results indicated that variations in the morphology of the reproductive organs of A. marginata ovum are mostly state dependent and less related to the size of the snail and thus could be used reliably to categorise the snails into reproductive states.