Oscheius

 

Contents

 

Rev 03/12/2024

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
Return to Oscheius Menu Ecosystem Functions and Services
Distribution Management
Return to Rhabditidae Menu Feeding  References
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Classification:

 

Chromadorea

  Rhabditia

    Rhabditida

      Rhabditoidea

        Rhabditidae

       
Oscheius Andrassy, 1976

Type species of the genus: Rhabditis insectivora Koerner, 1954

Genus named for Professor Gunther Osche in recogniton of his work on Rhabditidae.

   Synonymy of Heterorhabditoides with Oscheius is generally accepted (Kumar, et al., 2019)

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Morphology and Anatomy:

Historically, Oscheius dolichura (Schneider, 1866) was one of the first nematode species (before C. elegans) described to have an androdioceous mode of reproduction (Maupas, 1900; Feliox, 2006).

The genus Oscheius is comprised of two groups or clades, Dolichura and Insectivora (Sudhaus and Hooper 1994) which are currently recognized as separate subgenera, Dolichorhabditis and Oscheius, respectively. With a few exceptions (Torrini et al., 2015) entomopathogenic nematodes (EPNs) have occurred mainly in the Insectivorus group.

Species in the Dolichura group generally have a slender body, peloderan bursa, inconspicuous posterior phasmids and spicules with straight tip (no distal hook). Species in the Insectivora group have a wide body with 4 to 6 incisures each in the lateral fields, pseudopeloderan/leptoderan bursa, phasmids posterior to the last genital papillae and needle-like spicules with  distal hooks (Kumar et al., 2019; Torrini et al., 2015)..

Species identification of the genus is very challenging since morphological characters are very similar. The genus Oscheius includes 42 valid species belonging to the Insectivora (28) and Dolichura (14) groups (Tabassum et al., 2016). A detailed revision of the taxonomy of the genus is provided by Abolafia and Pena-Santiago (2019).

 Males:

Insectivora Group:


  • with spicules shaped like crochet needles, leptoderan bursa and non-expansile rectum.
  • (As of 2018, 43 species)

Dolichura Group:

  • with normal spicules, peloderan bursa and expansile rectum.
  • (As of 2018, 14 species)

 Ref: Ye et al., 2018

 

  • Stoma rhabditoid, tubular, about 3-4 times as long as wide.
  • Cheilostom not sclerotized.; Gymnostom sclerotized.
  • Esophagealcollar surrounding base of stoma.
  • Procorpus cylindrical; metacorpus not clearly differentiated.
  • Basal bulb globe-shaped with "grinder" plates.
  • Excretory pore at the level of basal bulb. Duct sclerotized
  • Cuticle finely striated
  • amphids pore-like on lateral lips
  • tail conical in both sexes

 

Females:

  • Reproductive system didelphic, amphidelphic, ovaries reflexed.
  • Vulva at mid-body, a transverse slit with side vulval flaps .

 

 


Body size range for the species of this genus in the database - Click:
 
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Distribution:

 

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Feeding:

 Bacterivorous on bacteria in decomposing insect body (necronemic)  or free-living bacterivores.

Some insect associated nematodes are described as insect parasitic. Andrassy (1976) described the genus Oscheius and its type species, O. insectivorus,and Sudhaus (2011) separated Oscheius species into an Insectivora group with leptoderan bursa, comprising 14 species and  a Dolichura group, with peloderan bursa, comprising 13 species. Some representatives of this genus are considered potentially entomopathogenicc based on habitat or associations, e.g., O. carolinensis  (Ye et al., 2010).

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Biology and Ecology:

 

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Life Cycle:

 

For Ecophysiological Parameters for this genus, click 
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Ecosystem Functions and Services:

Considered entomopathogenic.The following criteria characterize entomopathogenic nematodes (a modification of Koch's postulates):

Ref: Dillman, et al., 2012; Ye et al., 2018).

Under laboratory conditions, the nematode and associated bacteria have been shown to kill:

Ye et al. (2018)

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Management:

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References:

Abolafia, J., Pena-Santiago, R. 2019. Morphological and Molecular Characterization of Oscheius saproxylicus sp. n. (Rhabditida, Rhabditidae) From Decaying Wood in Spain, With New Insights into the Phylogeny of the Genus and a Revision of its Taxonomy. J. Nematology 51:  DOI: 10.21307/jofnem-2019-053

 

Andrassy, I. 1976. Evolution as a Basis for the Systematization of Nematodes. UK, Pitman. 228 pp.

 

Dillman, A.R., Chaston, J.M., Adams, B.J., Ciche, T.A., Goodrich-Blair, H., Stock, S.P., and Sternberg, P.W. 2012. An entomopathogenic nematode by any other name. PLoS Pathogen 8(3): e1002527, available at: https://doi.org/10.1371/journal.ppat.1002527.

 

Felix, M-A. 2006. Oscheius tipulae. WormBook: The Online Review of C. elegans Biology ï¿½

 

Kumar, P., Jamal, W., Somvanshi, V.S., Chauhan, K., Mumtaz, S. 2019. Description of Oscheius indicus n. sp. (Rhabditidae: Nematoda) from India. J. Nematology DOI: 10.21307/jofnem-2019-004.

 

Liu, Q.Z., Mracek, Z., Zhang, L.J., Puza, V., and Dong, L.M. 2012. Nematology 14:139-149.

Maupas E. 1900. Modes et formes de reproduction des n�matodes. Arch. Zool. exp. 8:463�624.

Schneider, A.F. 1866. Monographie der Nematoden (Berlin).

Sudhaus, W. 2011. Phylogenetic systemization and catalogue of paraphyletic Rhabditidae; (Secernentea: Nematoda). Journal of Nematode Morphology and Systematics 14:113-178.

 

Sudhaus, W. and Hooper, D.J. 1994. Rhabditis (Oscheius) guentheri sp. n., an unusual species with reduced posterior ovary, with observations on the Dolichura and Insectivora-groups (Nematoda: Rhabditidae). Nematologica, 40, 508�533. http://dx.doi.org/10.1163/003525994X00391

 

Torrini, G., Mazza, G., Carletti, B., Benvenuti, C., Roversi, P.F., Fanelli, E., De Luca, F., Troccoli, A., Tarasco, E. 2015. Oscheius onirici sp. n. (Nematoda: Rhabditidae): a new entomopathogenic nematode from an Italian cave. Zootaxa 3937: 533-548. DOI: https://doi.org/10.11646/zootaxa.3937.3.6

 

Tabassum, K.A., F. Shahina, K. Nasira and Y. I. Erum. 2016. Description of six new species of Oscheius Andrassy, 1976 (Nematoda: Rhabditida) from Pakistan with a key and diagnostic compendium to species of the genus. Pakistan Journal of Nematology 34:109-161..

 

Ye, W., Torres-Barragan, A. & Cardoza, Y.J. 2010. Oscheius carolinensis n. sp. (Nematoda: Rhabditidae), a potential entomopathogenic nematode from vermicompost. Nematology 12: 121-135.

 

Ye, W. Foye, S., MacGuidwin, A.E., Steffan, S. 2018. Incidence of Oscheius onirici (Nematoda: Rhabditidae), a potentially entomopathogenic nematode from the marshlands of Wisconsin, USA. J. Nematology 50:9-26. DOI: 10.21307/jofnem-2018-004

 

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Copyright  1999 by Howard Ferris.
Revised: March 12, 2024.

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