Bionomics of the slug-parasitic nematode Alloionema appendiculatum and its effect on the invasive pest slug Arion vulgaris.
Alloionema appendiculatum Schneider, 1859 (Rhabditida: Alloionematidae) is a common parasite of terrestrial molluscs capable of causing high snail mortality in heliculture. It has also been described as a parasite of the invasive slug Arion vulgaris Moquin-Tandon, 1855 (Pulmonata: Arionidae), a serious pest in central Europe. Nonetheless, our knowledge about the ecology of this nematode is poor. Our study aims to provide new information about some as yet unknown aspects of the biology of this species, mainly its prevalence, attraction to slug associated cues, development, progeny production, and influence on the mortality and feeding activity of its host. The results of our study provide new information about the saprobic life cycle and natural prevalence of the species, but also show that, in standard conditions, A. appendiculatum has a very weak influence on the mortality and feeding activity of A. vulgaris. We concede that the effect of A. appendiculatum on the slug host can be strongly influenced by bacterial associates, even though the role of bacteria in nematode development is questionable and needs further research. Based on our results, A. appendiculatum does not seem to be a suitable agent for the biocontrol of A. vulgaris.