The Relationship Of Oncomelania Hupensis Morphology And Structure Development Change And The Survival Rate

Through the research of Oncomelania hupensis’s external shape change during the growth period, we can get the relationship between the change of young snails’ whorl in the growth and the transition of life habit from aquatic to terraneous. The helicoid of newly-hatched snail is nearly clear, there has one spiral on the shell. The length and width is approximately same. With the growth, the shape will changes, the number of spiral will increases, the length of the shell will longer than width of it. The length-width ratio of newly-hatched snail is around1:1, the length-width ratio will be changed during the growth. When the length-width ratio reaches2.2:1, young snails will transits from aquatic to terraneous and have mating between male and female, which observed occur in July.In the research of Oncomelania hupensis’s interior structure, we get these results:young snail with four rotations has obvious gills, no gonad, the sex is undistinguishable, suit for aquatic. Young snail with five rotations has obvious gills, the gonad of male is not obviously, the penis of male has an embryonic form. Young snail with six rotations has obvious gills, both male and female’s gonad are obviously. The respirator and digestion systems have been formed. Young snail with seven rotations has obvious gills, gonad is obvious, each organ can be clearly seen under the microscope.In the research of Oncomelania hupensis’s hibernation survival rate, we find that in the same depth with four directions, the Oncomelania hupensis which live in the side direction has a higher hibernation survival rate, the lower side direction ones has a lower hibernation survival rate. The other directions’Oncomelania hupensis have the same hibernation survival rate.In the same directions with different depth, the hibernation which live in2cm depth has a higher survival rate, the lcm ones and the3cm is lower. The factor which probably leads this result is the effect of external environment. The Oncomelania hupensis which live in1cm depth is easier impacted by the external environment,3cm depth ones is easier covered by upper soil which also lead the lower survival rate.