Study on shell shape changes of filial generation Oncomelania hupensis snails in Weishan Lake region,Shandong Province / 中国血吸虫病防治杂志

ABSTRACT

Objective To explore the shape change characteristics of Oncomelania hupensis snail shell after the snails being passively migrated into Shandong intake area of the South-to-North Water Diversion Project. Methods The snails raised on the Dushan island in Weishan Lake region were captured,and 115 the first filial generation snails and 107 the second filial generation ones were selected. The length and width of shells and apertures,and the labial ridge thickness of those snails were measured,the longitudinal rib number of snail spiral was counted,and 107 parental snails were chosen as controls. Results The labial ridge thickness of the filial generation snail was significantly reduced with the increase of algebras,and the labial ridge thickness among the 3 generations had a significant difference(P<0.01). Both the length of snail shell and the width of snail apertures were de-creased,while the width of snail shell,the length of snail apertures,the multiplication product of snail aperture’s length and width and the longitudinal rib number of snail spiral were all increased. Conclusion The body size of Oncomelania snails in Weishan Lake region becomes smaller,and their shells become thinner,which indicates that the environment of the lake region is not suitable for snail breeding,and the snails have natural decay tendency with the extension of time.