An observation on the mimic ecology of the oncomelania hupensis in three-gorge-reservoir areas

Abstract

According to the modulation of three-gorge-reservoir water level, the two observation spots were established at Gaoyang Town and Jianshe Village in Xingshan County of Hubei Province in order to observe the survival and reproduction of the oncomelania under different ecological conditions. Our one-year observation revealed that most settled oncomelania died between June and August in the year and only a few of them survived the winter. The oncomelania hupensis’s survival rate in group I,II,III settled in Gaoyang Town was 10 %, 1 %, 0 %, respectively, and the oncomelania Sichuan’s 12. 5 %, 22. 5 %, 13. 5 %. The rates obtained from spots in Jianshe Village is 0 %, 2 %, 0 % and 9. 5 %, 19 %, 3 %, respectively. The survival rate of oncomelania Sichuan was higher than that of the oncomelania hupensis in the two spots. After draining the feeding pools, the soil samples were harvested and used for egg-hatching. The numbers of eggs that hatched in group 1, II in Gaoyang were 1 and 2, respectively. The young oncomelania were found in each spot pool after the drainage, suggesting that the local condition is favorable to the oncomelania and the mating season of each group oncomelania is from April to August with the most active mating time being from May to June.

Keywords

three-gorge-reservoir areas / ecological variation / oncomelania / reproduction