目的探讨湖北钉螺滇川亚种在垸内水网地区生存繁殖的可能性和期望生存时间。方法采用笼养法,将采自四川省丹棱县的湖北钉螺滇川亚种、湖北省江陵县实验区内的湖北钉螺指名亚种进行雌雄鉴定分离,分别以雌雄比1∶1配对后,放养在江陵县实验区的螺笼内,分别于3、6个月和9个月后,定期观察其生存和繁殖情况。将采集的滇川亚种钉螺采用室内瓷盘饲养法饲养,采用动物生存寿命表法计算滇川亚种钉螺在脱离原孳生环境后的期望生存时间。结果滇川亚种钉螺在同种及混合现场放养状态下,经过3个月和6个月后,存活率〉75%,至9个月后仍有20%以上的存活率。两个亚种钉螺3个月的存活率差异有统计学意义(23χ个月=38.641,P〈0.05),同一亚种雌螺与不同亚种雄螺放养后,雌螺存活率差异有统计学意义(2aχf=13.255,P〈0.05;2cχg=4.882,P〈0.05);9个月后各组均可查获数量不等的子代钉螺。室内实验推算滇川亚种钉螺和指名亚种钉螺的期望生存时间分别为35.84 d和41.16 d。结论滇川亚种钉螺离开原孳生环境后有足够的存活时间完成远距离被动迁移;迁入水网地区后能够继续生存繁殖,并能产生子代。
Objective To understand the possibility of the survival and reproduction of Oncomelania hupensis robertsoni snails in water network regions in Hubei Province,as well as their expected lifespan after leaving the original propagating environment,so as to provide the basic data and precondition for reducing the infection rates of O.h.hupensis in the lake regions.Methods The O.h.robertsoni snails,smooth-shell,were collected from Danling County,Sichuan Province,and raised in the cages in Baimasi Town of Jiangling County,Hubei Province.The survival and reproduction abilities of the snails were observed on regular time.The O.h.hupensis from Jiangling County,Hubei Province was studied as a control group.The expected lifespan of snails was calculated by using the animal life table.Results After 3-,6-month,the survival rates of O.h.robertsoni were maintained more than 75% in the homogeneous and mixed living conditions,still above 20% after 9-month.Compared with the control group,there was a statistically significant difference in the 3-month group(χ2three months=38.641,P0.05),there was a significant difference between the homogeneous and mixed groups for the female snail survival rates(χ2af=13.255,P0.05,χ2cg=4.882,P0.05),but not in the 6-,9-month groups(χ2six months=3.253,P0.05;χ2nine months=5.017,P0.05).Filial generation snails were found after nine months in each group.The expected lifespan of O.h.hupensis was 41.16 d and that of O.h.robertsoni was 35.84 d in the laboratory.Conclusions The O.h.robertsoni snails from foreign lands can continually survive and reproduce in water network regions in Hubei.O.h.robertsoni snails have enough survival time to passive remote diffusion after leaving the original propagating environments.