上海市青浦区钉螺再生性研究

Study on the reproducibility of Oncomelania snails in Qingpu district of Shanghai

目的了解钉螺在青浦区环境中再生的能力。方法采用环境法取全区10个镇(街道)的10块土壤作为试验组及近年来上海市有螺地区的松江、金山区2块土壤作为对照组,随机分配植入试验基地。将不同颜料标记后的雌雄钉螺各25只采用随机法放入每个试验地块中,经过1年的试验,观察是否有新螺出现,以及越冬后次年钉螺的生存状况。结果自2008年5月22日开始放养钉螺后,经过147d首次发现有新螺出现,钉螺繁殖、孵化时的月平均气温为27.1～34.3℃,至2009年5月17日,所有试验地块均有新螺出现,春季钉螺产卵、孵化时的月平均温度仅为3.2～9.8℃。试验前后土壤pH值分别为5.5±0.7和5.4±1.0,配对t检验显示差异无统计学意义(t=0.17,P=0.87)。结论钉螺在青浦区可以再生,并可以越冬生存;春季钉螺可能在较低温度下即可繁殖孵化。

Objective To explore the reproductive capacity of Oncomelania snails in the environment in Qingpu district.Methods Soils that were taken by environmental methods from 10 sampling sites in all the ten towns of Qingpu district served as the test group,with soil samples taken in the same way from Songjiang district and Jinshan district where O.snails appeared in recent years used as the control group.All these samples were randomized as the experimental fields.O.snails marked by different colors were divided into 12 groups,25 males and 25 females for each group.The O.snails were also randomized to the fields to see whether the second birth of snails would appear and their survival status over the winter.Results It was on May 22nd,2008 that the O.snails were stocked and the second generation was first found 147 days later,with the second generation of O.snails appearing in every field of the experimental base before May 17th,2009.The average monthly temperature for snails to reproduce or incubate was between 27.1 ℃ to 34.3 ℃,with the value being between 3.2 ℃ to 9.8 ℃ for the nails to do the same things in Spring.Statistical analysis by the paired t-test showed that there was no significant difference（t=0.17,P=0.87） in the average pH values of the soils before and after the experiment,which were 5.5±0.7 versus 5.4±1.0.Conclusion O.snails are able reproduce in Qingpu district with the ability to survive over winters,relatively low temperature needed in spring for them to reproduce.