Morphological and Ecological Characterization of <I>Steinernema feltiae</I> (Rhabditida: Steinernematidae) Rioja Strain Isolated from <I>Bibio hortulanus</I> (Diptera: Bibionidae) in Spain


  • R. Campos-Herrera
  • M. Escuer
  • L. Robertson
  • C. Gutierrez


molecular markers, natural host, Spain, Steinernema feltiae, virulence.


A new strain of Steinernema feltiae (Rhabditida: Steinernematidae) was isolated in La Rioja (Spain) from larvae of Bibio hortulanus (Diptera: Bibionidae). A comparative morphometric analysis of this new strain and four additional S. feltiae isolates was performed. Although significant differences in morphometric measurements were observed, PCR-RFLP profiles and sequence analysis of the ITS region of rDNA confirmed the identity of the new strain as A2 RFLP type of S. feltiae. A comparative morphometric study among nematodes from three hosts, Galleria mellonella (Lepidoptera: Pyralidae), Spodoptera littoralis (Lepidoptera: Noctuidae) and B. hortulanus, was conducted. Ecological characterization of the Rioja isolate was performed in G. mellonella larvae. Larval mortality was 75.3 and 78.12% in penetration and sand column assays, respectively, and the percentage of penetrating infective juveniles was 12.0 and 2.8% in these assays. Larval mortality in the one-on-one bioassay was 4.2 %, and in exposure-time bioassays, it was 50% at 11.25 hours. Relationships between morphometric characteristics and host mortality are discussed for this new strain of entomopathogenic nematode.