Wiles Crystal M, Bolek Matthew G
Department of Zoology, Oklahoma State University, Stillwater, Oklahoma, USA.
Folia Parasitol (Praha). 2015 Jan 1;62:2015.019. doi: 10.14411/fp.2015.019.
Third-stage larvae of the nematode Serpinema trispinosum (Leidy, 1852) were collected from the midgut of four of five species of adult damselflies (Zygoptera) from a non-irrigated restored semipermanent wetland located in Stillwater, Oklahoma, USA. Of the four infected damselfly species, prevalence and mean abundance was highest for the southern spreadwing, Lestes disjunctus australis Walker (10%, 0.2 ± 0.8) and lowest for the familiar bluet, Enallagma civile (Hagen) (2.5%, 0.04 ± 0.3); whereas mean intensities were lowest for the citrine forktail, Ischnura hastata (Say) (1.5 ± 0.5) and the eastern forktail, Ischnura verticalis (Say) (1.0 ± 0). This is the first record of larvae of S. trispinosum from damselflies. Serpinema trispinosum adults have been reported from 18 species of North and Central American freshwater turtles, whereas microcrustaceans such as copepods serve as intermediate hosts and snails, fish and amphibians serve as paratenic hosts in this nematode's life cycle. However, dietary studies of the 18 species of freshwater turtles reported as definitive hosts for S. trispinosum indicate that aquatic insects including damselflies are more commonly reported in turtle diets than are fish or amphibians. Additionally, unlike snails and amphibians, larval damselflies predominantly feed on microcrustaceans, and our observation of S. trispinosum infecting damselflies may reflect the importance of these insects as paratenic hosts. In the present study, we provide new host information and measurements for third-stage larvae of S. trispinosum from damselfly hosts along with measurements for adult male and female S. trispinosum from turtle hosts from Oklahoma, USA.
线虫三棘丝蛇线虫（Serpinema trispinosum，Leidy，1852）的第三期幼虫是从美国俄克拉荷马州斯蒂尔沃特一处未经灌溉的恢复性半永久性湿地中采集的5种成年豆娘（均翅亚目）中的4种的中肠内获取的。在这4种受感染的豆娘物种中，南方展翅豆娘（Lestes disjunctus australis Walker）的感染率和平均丰度最高（10%，0.2±0.8），而常见蓝纹豆娘（Enallagma civile (Hagen)）的感染率和平均丰度最低（2.5%，0.04±0.3）；而柠檬尾叉尾豆娘（Ischnura hastata (Say)）（1.5±0.5）和东部尾叉尾豆娘（Ischnura verticalis (Say)）（1.0±0）的平均感染强度最低。这是三棘丝蛇线虫幼虫在豆娘体内的首次记录。三棘丝蛇线虫的成虫已在18种北美和中美洲淡水龟体内被发现，而诸如桡足类等小型甲壳动物是该线虫生命周期中的中间宿主，蜗牛、鱼类和两栖动物则是转续宿主。然而，对被报道为三棘丝蛇线虫终末宿主的18种淡水龟的饮食研究表明，包括豆娘在内的水生昆虫在龟的饮食中比鱼类或两栖动物更常见。此外，与蜗牛和两栖动物不同，豆娘幼虫主要以小型甲壳动物为食，而我们观察到三棘丝蛇线虫感染豆娘可能反映了这些昆虫作为转续宿主的重要性。在本研究中，我们提供了来自豆娘宿主的三棘丝蛇线虫第三期幼虫的新宿主信息和测量数据，以及来自美国俄克拉荷马州龟宿主的三棘丝蛇线虫成年雌雄虫的测量数据。
