Steinernema rarum

Steinernema rarum	Contents	Rev 07/12/2025
	Classification	Biology and Ecology
	Morphology and Anatomy	Life Cycle
Return to Steinernema Menu		Ecosystem Functions and Services
	Distribution	Management
Return to Steinernematidae Menu	Feeding	References
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Morphology and Anatomy:

Review general morphological characteristics of genus Steinernema

Reported median body size for this species (Length mm; width micrometers; weight micrograms) - Click:

Distribution:

The dauer stage infective juvenile invades invades the body of the host insect and resumes development it releases releasing endosymbiotic pathogenic bacteria (Xanorhabdus sp in this case) from its intestine into the host. The nematode and bacterial symbiont kill the insect and convert the carcass into an incubator for the nematode-bacterial pair. When the carcass is exhausted of nutrients, a subsequent generation of IJs, each carrying pathogenic bacteria, disperse into the soil. (Dziedziech et al. 2020).

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Biology and Ecology:

The following criteria characterize the general biology of entomopathogenic nematodes (a modification of Koch's postulates):

Carry a pathogenic bacterium (Xenorhabdus spp.) in the dauer juvenile (infective) stage.
Dauer juveniles actively seek and penetrate insect hosts.
Release the bacterium in the insect host.
There is rapid death of the insect host.
Both nematode and bacterium reproduce within the insect host; the IJ develops into a third-stage feeding larva and into males and females in the case of Steinernema (in Heterorhabditis tthe IJs develop mainly into hermaphroditic adults).
The bacterium is re-associated with the new generations of the nematode.
Infective juvenile nematodes emerge from the cadaver of the insect host

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

Xenorhabdus is a genus of motile, gram-negative proteobacteria from the family of the Morganellaceae. Species of the genus are only known to live in symbiosis with Steinernema spp.

The nematode cannot establish within the insect host without the bacteria.

Some species of Xenorhabdus are virulent when injected directly into the insect host while other species appear to need phoresy with the nematode into the insect (Gaudriault et al, 2014).

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Life Cycle:

Ecophysiological Parameters:

For Ecophysiological Parameters for this species, click	If species level data are not available, click for genus level parameters

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Ecosystem Functions and Services:

Entomopathogenic nematodes.

The small hive beetle (SHB), Aethina tumida Murray (Coleoptera: Nitidulidae), is a threat to the European-derived western honeybee (Apis mellifera Linnaeus) populations globally. The last instar of the SHB is a non-feeding, wandering stage that exits the hive to pupate in the soil. Laboratory biological control experiments indicate moderate virulence of S. rarum against wandering larvae of SHB (Mbala et al., 2925).

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Management:

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References:

Bhat, A. H., Chaubey, A. K., and Askary, T. H. 2020. Global distribution of entomopathogenic nematodes, Steinernema and Heterorhabditis. Egyptian Journal of Biological Pest Control 30:1-15.

Chaston, J. M., Suen, G., Tucker, S. L., Andersen, A. W., Bhasin, A., Bode, E., Bode, H. B., Brachmann, A. O., Cowles, C. E., Cowles, K. N., Darby, C., Leon, L., de Drace, K., Du, Z., Givaudan, A., Tran, E. E. H., Jewell, K. A., Knack, J. J., Krasomil-Osterfeld, K. C., and Goodrich-Blair, H. 2011. The entomopathogenic bacterial endosymbionts Xenorhabdus and Photorhabdus: Convergent lifestyles from divergent genomes. PLOS ONE 6:e27909. https://doi.org/10.1371/journal. pone.0027909

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.

Dziedziech A, Shivankar S, Theopold U. 2020. High-resolution infection kinetics of entomopathogenic nematodes entering Drosophila melanogaster. Insects. 11:60. doi: 10.3390/insects11010060.

Gaudriault S., Ogier J.C.; Pagu, S.; Bisch G.; Chiapello H.; M'digue C.; Rouy Z.; Teyssier C.; Vincent S.; Tailliez P.; Guivaudan A. (2014). Attenued Virulence And Genomic Reductive Evolution In The Entomopathogenic Bacterial Symbiont Species, Xenorhabdus poinarii. Genome Biology and Evolution. 6: 1495"1513.

Hunt, D.J. and Nguyen, K.B. 2016. Advances in Entonmopathogenic Nematode Taxonomy and Phylogeny. Nematology Monographs and Perspecives 12 Brill, Leiden.

Kaya, H.K., and Gaugler, R. 1993. Entomopathogenic nematodes. Annual Review of Entomology 38: 181-206.

Mbala, G.M., Browning, K., Wansi, S., Li, Y., Ellis, J.D., Kanga, L.H., Shapiro-Ilan, D. I. 2025. Comparative Virulence of Entomopathogenic Nematodes to the Small Hive Beetle (Aethina tumida Murray, Coleoptera: Nitidulidae). J. Nematology 57: | DOI: 10.2478/jofnem-2025-0011

Nguyen, K.B. and Smart, G.C. 1996. Identification of entomopathogenic nematodes in the Steinernematidae and Heterorhabditidae. J. Nemtology 28:286-300.

Shapiro-Ilan, D. I., Gouge, D. H. and Koppenhofer, A. M. 2002. Factors affecting commercial success: case studies in cotton, turf and citrus, In Gaugler, R. (Ed.), Entomopathogenic Nematology CABI Publishing, Wallingford, pp. 333-356.

Spiridonov, S. E. and Subbotin, S. A. 2016. Phylogeny and phylogeography of Heterorhabditis and Steinernema. In: Hunt, D.J. & Nguyen, K.B. (Eds). Advances in entomopathogenic nematode taxonomy and phylogeny. Nematology Monographs and Perspectives 12 (Series Editors: Hunt, D.J. & Perry, R.N.). Leiden, The Netherlands, Brill, pp. 413-427. DOI: 10.1163/9789004285347_007

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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