Department of Zoology, Oregon State University, Corvallis, OR 97331, USA.
Parasit Vectors. 2012 Feb 1;5:24. doi: 10.1186/1756-3305-5-24.
It is rare to find terrestrial nematode lineages parasitizing arthropods inhabiting the intertidal or littoral zone of the oceans. During an ecological study along the Oregon dunes, an allantonematid nematode (Tylenchomorpha: Allantonematidae) was discovered parasitizing the intertidal shore bug, Saldula laticollis (Reuter)(Hemiptera: Saldidae). This shore bug is adapted to an intertidal environment and can survive short periods of submergence during high tides. The present study describes the nematode parasite and discusses aspects of its development, ecology and evolution.
Adults and last instar nymphs of S. laticollis (Hemiptera: Saldidae) were collected from the high intertidal zone among clumps of Juncus L. (Juncaceae) plants at Waldport, Oregon on October 3, 2011. The bugs were dissected in 1% saline solution and the nematodes killed in 1% Ringers solution and immediately fixed in 5% formalin (at 20°C). Third stage juveniles removed from infected hosts were maintained in 1% saline solution until they matured to the adult stage, molted and mated.
Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae) is described from last instar nymphs and adults of the intertidal bug, Saldula laticollis on the Oregon coast. The new genus can be distinguished from other genera in the Allantonematidae by a stylet lacking basal knobs in both sexes, an excretory pore located behind the nerve ring, ribbed spicules, a gubernaculum, the absence of a bursa and the elongate-tubular shape of the ovoviviparous parasitic females. Studies of the organogenesis of Halophilanema showed development to third stage juveniles in the uterus of parasitic females. Maturation to the free-living adults and mating occurred in the environment. The incidence of infection of S. laticollis ranged from 0% to 85% depending on the microhabitat in the intertidal zone.
Based on the habitat and morphological characters, it is proposed that Halophilanema adapted a parasitic existence fairly recently, evolutionarily speaking. It was probably a free-living intertidal or shore nematode that fed on microorganisms, especially fungi, in the intertidal habitat and became parasitic after saldids entered the environment. Halophilanema represents the first described nematode parasite of an intertidal insect.
在海洋的潮间带或滨海区中，寄生节肢动物的陆生线虫谱系极为罕见。在沿俄勒冈沙丘进行的一项生态研究中，发现了一种寄生在潮间带岸虱、Saldula laticollis（Reuter）（半翅目：Saldidae）体内的全尾线虫（Tylenchomorpha：Allantonematidae）。这种岸虱适应潮间带环境，能够在涨潮时短暂淹没。本研究描述了这种线虫寄生虫，并讨论了其发育、生态和进化的各个方面。
2011 年 10 月 3 日，在俄勒冈州沃尔德波特的 Juncus L.（莎草科）植物丛中采集高潮间带的 S. laticollis（半翅目：Saldidae）成虫和最后龄若虫。在 1%盐水中对虫子进行解剖，在 1%林格氏溶液中杀死线虫，然后立即在 20°C 下用 5%福尔马林固定。从受感染的宿主中取出的第三龄幼虫保存在 1%盐水中，直到它们成熟为成虫、蜕皮和交配。
Halophilanema prolata n. gen., n. sp.（线虫：Allantonematidae）从俄勒冈海岸潮间带岸虱的最后龄若虫和成虫中描述。新属可通过两性体的 Stylet 缺乏基部节结、排泄孔位于神经环后、具肋状 spicules、 gubernaculum、无囊和卵胎生寄生雌虫的长管状形状与 Allantonematidae 中的其他属区分开来。Halophilanema 的器官发生研究表明，第三龄幼虫在寄生雌虫的子宫中发育。在环境中成熟为自由生活的成虫并交配。S. laticollis 的感染率因潮间带微生境而异，范围从 0%到 85%不等。
基于栖息地和形态特征，从进化角度来看，Halophilanema 最近适应了寄生生活。它可能是一种自由生活的潮间带或海岸线虫，以潮间带栖息地中的微生物为食，尤其是真菌，在 Saldids 进入环境后成为寄生虫。Halophilanema 代表了描述的第一种潮间带昆虫线虫寄生虫。
