The chemotaxis responses of soil nematodes have been well studied in bacteriophagic nematodes, plant-parasitic nematodes, entomopathogenic nematodes, and to a lesser extent malacopathogenic nematodes. Free-living stages of parasitic nematodes often use chemotaxis to locate hosts. In this study, we compared the chemotaxis profile of 2 slug-associated nematodes with overlapping host ranges. Phasmarhabditis californica is a facultative parasite that has been shown to express strain-dependent variation in chemoattraction profile. We tested 4 slug species to determine the attraction index of a Canadian strain of Ph. californica and a sympatric necromenic nematode, Pristionchus entomophagus. When tested against a control (distilled water), Ph. californica showed a clear (positive) attraction towards the mucus of slugs Ambigolimax valentianus, Arion rufus, and Arion fasciatus, but not Deroceras reticulatum. However, when given a choice between the mucus of D. reticulatum and Ar. fasciatus in a pairwise test, Ph. californica was strongly attracted to the former. Other pairwise comparisons did not reveal a clear preference for either slug species in the following pairs: D. reticulatum–Ar. rufus, Am. valentianus–Ar. rufus, D. reticulatum–Am. valentianus. The chemotaxis assay for Pr. entomophagus showed an attraction toward D. reticulatum and Ar. fasciatus (tested against controls); the attraction index for Am. valentianus was positive, but this was not statistically significant. In contrast, the attraction index for Ar. rufus was negative, suggesting possible repulsion to the mucus of this slug species. Given that Pr. entomophagus and Ph. californica occupy overlapping habitats, utilize similar hosts, and exhibit similar chemotaxis profiles, there is a potential for direct interaction between these 2 nematodes. Like other members of the genus Pristionchus, Pr. entomophagus may be able to prey upon the co-occurring Ph. californica, such antagonistic interactions could have important implications for the coexistence of these 2 species and Ph. californica in particular as a biocontrol agent against pestiferous slugs.

土壤线虫的趋化反应已在食菌线虫、植物寄生线虫、昆虫病原线虫以及较小程度上的马拉病线虫中得到了深入研究。寄生线虫的自由生活阶段经常利用趋化性来定位宿主。在这项研究中，我们比较了两种具有重叠宿主范围的蛞蝓相关线虫的趋化性特征。加州枯萎病菌是一种兼性寄生虫，已被证明在化学吸引谱中表现出菌株依赖性变异。我们测试了 4 种蛞蝓物种，以确定加拿大的加州Ph. californica品系和同域死灵线虫Pristionchus entophagus的吸引力指数。当与对照（蒸馏水）进行测试时，Ph. californica对Ambigolimax valentianus、Arion rufus和Arion fasciatus的粘液表现出明显的（正）吸引力，但对Deroceras reticulatum则没有。然而，当在D. reticulatum和Ar的粘液之间进行选择时。在成对测试中，Ph. californica被前者强烈吸引。其他成对比较并没有显示出对以下对中的任一蛞蝓物种的明显偏好：D. reticulatum – Ar。鲁弗斯，Am. 瓦伦提亚努斯– Ar. rufus，D. reticulatum – Am。瓦伦蒂安努斯。Pr的趋化性测定。entophagus对D. reticulatum和Ar表现出吸引力。fasciatus（针对对照进行测试）；Am的吸引力指数。valentianus呈阳性，但这没有统计学意义。相比之下，Ar 的吸引力指数。rufus呈阴性，表明这种蛞蝓的粘液可能具有排斥性。鉴于Pr。食虫线虫和加州Ph. californica占据重叠的栖息地，利用相似的宿主，并表现出相似的趋化性特征，这两种线虫之间存在直接相互作用的潜力。像Pristionchus属的其他成员一样，Pr。食虫虫可能能够捕食同时存在的加州Ph. californica ，这种拮抗相互作用可能对这两个物种和Ph. californica的共存具有重要意义，特别是作为对抗瘟疫蛞蝓的生物防治剂。