江滩异地钉螺生存繁殖的现场研究

FIELD STUDY ON SURVIVAL AND REPRODUCTION OF ONCOMELANIA HUPENSIS SNAILS FROM FOREIGN LANDS IN MARSHLAND

目的 观察江滩外来钉螺的生存、繁殖及螺口动态消长情况 ,为防制工作提供科学依据。 方法 捕捉安徽和南京江滩钉螺进行人工配对后在仪征有螺滩地采用现场螺笼放养、定期观察的方法 ,进行钉螺的生存繁殖、螺口消长及钉螺的越冬死亡观察。 结果 安徽、南京和仪征三地钉螺的越冬死亡率分别为 16.84%、19.0 0 %和 17.17% ,差异均无显著性 (P >0 .0 5 ) ;年生存率分别为 11.86%、19.64 %和 2 6.2 5 % ,其中安徽组与仪征对照组差异显著 (P <0 .0 5 ) ,而安徽与南京两组间差异无显著性 (P >0 .0 5 ) ;各组钉螺的生殖腺发育正常 ,月平均产卵数和螺卵孵化率等差异亦无显著性 (P >0 .0 5 ) ,但安徽与南京两地钉螺的产卵高峰期较仪征对照组钉螺推迟约 2 0d左右。 结论 异地江滩钉螺迁入仪征江滩后能够生长繁殖 ,但在短期内不会构成螺情的迅速增殖和蔓延 ,提示今后在螺情较轻的滩地或地区 ,加强螺情监测是关键 ,但对高密度有螺滩地 ,仍应强化灭螺措施 ,以进一步降低钉螺密度而减少钉螺的扩散。

Objective To observe the survival, reproduction and dynamic changes of Oncomelania hupensis snails from foreign lands in Yizheng marshland, which will provide the basic theory for developing control strategy. Methods The snails from Anhui and Nanjing were collected and mated in the lab, then were raised in the cages on the Yizheng marshland. The survival, reproduction and dynamic changes of snails were observed on regular time. Local snails in Yizheng were as control. Results The death rate in winter of snails in Anhui, Nanjing and Yizheng was 16.84%, 19.00% and 17.17% respectively. There was no significant difference in all groups. The survival rate was 11.86%,19.64% and 26.25%, correspondingly. There was significant difference between Anhui and Yizheng groups. No significant difference was found between Anhui and Nanjing groups. The development of glands of snails from all groups was as normal. There was no significant difference of egg production and hatching in all groups, but the egg production peak time of snails from Anhui and Nanjing groups was about 20 days later than that of control group. Conclusion The snails from foreign lands can survive in Yizheng marshland, but which will not cause the snail increasing and spreading in short term. It is necessary to strengthen snail surveillance in the lower snail infested area, while in the higher snail infested area it still need to reinforce the molloucucide strategy to decrease the snail density and avoid spreading.