Tieszen K L, Molyneux D H
Department of Biological Sciences, University of Salford, United Kingdom.
J Protozool. 1989 Sep-Oct;36(5):519-23. doi: 10.1111/j.1550-7408.1989.tb01088.x.
An investigation of transmission and ecology of the monogenetic trypanosomatids, Blastocrithidia gerridis and Crithidia flexonema, in Gerris is described. Motile free-living flagellates of both species were found in the faeces of Gerris and in the water on which the bugs inhabited. Transmission of both trypanosomatid species occurred from naturally infected wild-caught bugs to flagellate-free laboratory-bred bugs via water. Crithidia flexonema was also transmitted to laboratory-bred bugs after being isolated in culture. Observations of experimentally infected bugs indicate that C. flexonema flagellates are imbibed and pass through the fore- and midgut to the hindgut where they become attached and multiply. There was no evidence to suggest transovarial transmission. In a 3-yr investigation into the prevalence of trypanosomatids in a natural population of adult Gerris odontogaster, it was found that the infection rate varied between 19% and 100%. There was no significant difference in infection rates between females and males. The infection rate peaked for each year in late spring or early summer. The significance of these results is discussed in relation to the ecology and behaviour of Gerris. The results indicate that the infections are maintained in hibernating bugs over winter.
本文描述了对水生蝽象中单亲毛滴虫（Blastocrithidia gerridis和Crithidia flexonema）的传播和生态学研究。在水生蝽象的粪便以及其栖息的水体中均发现了这两种能动的自由生活鞭毛虫。两种毛滴虫均通过水从自然感染的野生捕获蝽象传播至无鞭毛虫的实验室饲养蝽象。Crithidia flexonema在培养物中分离后也可传播至实验室饲养的蝽象。对实验感染蝽象的观察表明，C. flexonema鞭毛虫被摄入后穿过前肠和中肠到达后肠，在那里附着并繁殖。没有证据表明存在经卵传播。在一项对成年齿腹真蝽自然种群中毛滴虫流行率的为期3年的调查中，发现感染率在19%至100%之间变化。雌性和雄性之间的感染率没有显著差异。每年的感染率在春末或夏初达到峰值。结合水生蝽象的生态学和行为对这些结果的意义进行了讨论。结果表明，感染在冬眠的蝽象中越冬得以维持。
