Abathymermis		Contents		Rev: 05/26/2025
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Abathymermis Menu				Ecosystem Functions and Services
		Distribution		Management
Return to Mermithidae Menu		Feeding		References
		Go to Nemaplex Main Menu		Go to Dictionary of Terminology

Type species of the genus: Abathymermis tenuicauda (Rubtsov, 1967) Rubtsov, 1971

    Synonyms:

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Morphology and Anatomy:

• Cuticle thin without crossing fibers
• Constrtiction in cervical region.
• Six cephalic papillae
• Mouth terminal with short buccal funnel
• Amphids oval
• Trophosome present
• Some species sexually reproducing, others capable of parthenogenes

Female:

• Vagina barrel- or bell-shaped; vaginal canal straight and perpendicular to body axis
• Vulva at mid-body

Male:

• Two short spicules
• Genital papillae in 3 rows, few in number

Pre-parasitic larvae armed with stylet.

Ref: Johnson and Kleve, 1995

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Distribution:

Freshwater mermithids

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Feeding:

Food Sources and Feeding strategies for the genus Abathymermis

Species of the genus Abathymermis have been describe parasitizing chironomid midges from freshwater lakes

• As with other Mermithidae, there is a stichosome consisting of a longitudinal serial duplication of esophageal glands (stichocytes, usually about 16) which are exterior to the esophagus musculature, each with a duct into the esophageal lumen

•  In the later stages of development, stichosome separates from the intestine, which becomes a trophosome in which the walls and lumen of the intestine disappear resulting in a syncyteal structure. with no anal opening to the exterior.

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Biology and Ecology:

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Life Cycle:

Typical of aquatic mermithids:

•  the post-parasitic larva emerges from tthe larva or adult of an insect host, molts to the adult stage, mates and deposits eggs in about a week.

• eggs hatch in a week and the pre-parasitic larva  penetrates into the haemocoel of the larva of an insect host and becomes parasitic.

• the parasitic larva is the only feeding stage and nutrients from the host are absorbed through the cuticle; the pre-parasitic stage survives on nutrients stored in the egg, the post-parasitic and adults stages utilize nutrients stored in the trophosome during the parasitic stage.

• the male dies after mating, the female dies after egg depositions (Johnson and Kleve, 1995)

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Ecosystem Functions and Services:

Potential for biological control of aquatic insect pests (Kumar et al., 2023,

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Management:

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References:

Johnson, A.A. and Kleve, M.G. 1995. Abathymermis fiseri n.sp. and Abathymermis shocki n. sp. (Nematoda: Mermithidae) from midge (Diptera: Chironomidae) imagos emerging from Lake Itasca, Minnesota, USA. Invertebrate Biology 114: 19-26.

Ferris, H. 2007. Stichosomida. McGraw-Hill Encyclopedia of Science & Technology. http://accesscience.com/abstract.aspx

Kumar, D., Nagal, P., Sidhu, H.S., Ranga, P., Kumari, P. 2023. Role of Mermithid Nematodes in the Management of Agricultural and Household Insect Pests: A review. Environment and Ecology 41:2890-2899.

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Copyright 1999 by Howard Ferris.
Revised: May 26, 2025.