Phasmarhabditis bonaquaense n. sp. is described and illustrated from the body of Malacolimax tenellus, from the locality of České Švýcary near the village of Dobrá Voda, the Czech Republic. Females are characterized by a body length of 2349 (1878–2626) µm and a cupola shaped tail with a long hyaline hair-like tail tip. Extremely prominent papilla-like phasmids present. Males 1829 (1414–2121) µm long. Peloderan bursa with nine pairs of rays (papillae), 1/1/1/2/1/3. One non-paired apparent papilla-like structure located near the ventral appendage anterior to the cloaca. Prominent papilla-like phasmids located close to the tail tip. Small subunit (18S), ITS, and D2-D3 expansion segments of the large subunit of ribosomal DNA were used to analyze the phylogenetic relationships of sequenced species in the genus Phasmarhabditis and other closely related species. Phasmarhabditis bonaquaense n. sp. varied from other related nematodes both in morphological characterizations and phylogenetic analysis. The life cycle of the newly described species is not well known but it is probably a facultative, mollusc-parasitic nematode able to survive permanently in the saprobic phase on decaying organic matter.

The effect of different growing substrates on the development of the slug parasite Phasmarhabditis hermaphrodita has been studied in a series of laboratory experiments. Wild, laboratory and Nemaslug strains of P. hermaphrodita and their monoxenic counterparts with Moraxella osloensis (CCM 5605T) were reared on homogenised pig kidney, Deroceras reticulatum, Arion lusitanicus, and Galleria mellonella, the faeces of D. reticulatum and A. lusitanicus, or leaf compost. Development time, yield, lipid reserves and the body length of nematodes were assessed. All P. hermaphrodita strains were able to grow and reproduce on all tested substrates; however, yields were markedly higher on invertebrate media. Lipid content and body size varied across the substrates and strains. A uniform response of all nematode strains and the most dramatic differences among substrates were recorded in yields, which could indicate that the quality of the substrate is expressed mainly in yield. Monoxenized strains had higher yield, length, lipid content and shorter development time. In general, the strain differences between the observed parameters were most likely due to different bacterial associates. The dramatic differences in yields on invertebrate substrates, in comparison to the others, illustrate the evolutionary advantage of the association of nematodes with invertebrates.

Entomopathogenic nematodes and fungi are globally distributed soil organisms that are frequently used as bioagents in biological control and integrated pest management. Many studies have demonstrated that the combination of biocontrol agents can increase their efficacy against target hosts. In our study, we focused on another potential benefit of the synergy of two species of nematodes, Steinernema feltiae and Heterorhabditis bacteriophora, and the fungus Isaria fumosorosea. According to our hypothesis, these nematodes may be able to disseminate this fungus into the environment. To test this hypothesis, we studied fungal dispersal by the nematodes in different arenas, including potato dextrose agar (PDA) plates, sand heaps, sand barriers, and glass tubes filled with soil. The results of our study showed, for the first time, that the spreading of both conidia and blastospores of I. fumosorosea is significantly enhanced by the presence of entomopathogenic nematodes, but the efficacy of dissemination is negatively influenced by the heterogeneity of the testing arena. We also found that H. bacteriophora spread fungi more effectively than S. feltiae. This phenomenon could be explained by the differences in the presence and persistence of second-stage cuticles or by different foraging behavior. Finally, we observed that blastospores are disseminated more effectively than conidia, which might be due to the different adherence of these spores (conidia are hydrophobic, while blastospores are hydrophilic). The obtained results showed that entomopathogenic nematodes (EPNs) can enhance the efficiency of fungal dispersal.

Surveying the biodiversity of entomopathogenic nematodes in Zulia and Falcón states, north-western Venezuela, two populations of a newSteinernemaspecies were isolated from soil samples. Morphological, morphometric and molecular data indicate that the new species belong to the ‘bicornutum-group’ ofSteinernema. The new species can be separated from the other species of the group due to the size and shape of their spicules, which are the shortest within the group, and the presence of prominent deirids in the male of both generations at basal bulb level. Lateral field with eight ridges at mid-body of which submarginal ridges are less distinct, but the third and sixth ridges eventually become wider posteriorly to form the last two ridges. Female possesses small but distinct double epiptygmata and anal swellings present in 50% of the specimens. Phylogenetic analyses of thebicornutum-group based on both ITS and D2-D3 regions showed a clear separation of the new species from all other species. We describe these two populations and designate them asSteinernema papillatumn. sp.