Mermithid nematodes
symphylans new

Mermithid worm

Recently I noticed the whirling antics of a tiny but long worm. I grabbed my camera and captured some of the interesting behavior of what turned out to be an insect parasitic nematode, Mermis nigrescens. According to OSU zoologist, George Poinar, this is a female nematode in the process of ovipositing (egg laying) onto the spinach leaves. These eggs, when eaten by a plant-feeding insect like a grasshopper or caterpillar, contains an infective stage nematode, which is ready to penetrate into the body of a potential host as soon as it is swallowed.

These nematodes come out during wet periods and retreat when the sun comes out. They have an eye at the anterior end of the female worms that acts as a photoreceptor.

Video of the mermithid nematode, Mermis nigrescens

Mermithid worm video


Capinera, John. 2011. Featured Creatures. Grasshopper nematode: Mermis nigrescens.

Poinar, G . O ., Jr . 1985 . Mermithid (Nematoda) parasites of spiders and harvestmen . J . Arachnol . , 13 :121-128 .

Cranshaw, Whitney. Weird Worms: Horsehair Worm and the Grasshopper Nematode. Colorado State University Extension.

Hammond, G. 2009. "Mermis nigrescens" (On-line), Animal Diversity Web. Accessed June 03, 2010.

University of Nebraska - Lincoln. Plant and Insect Parasitic Nematodes: Mermis nigrescens. Nice line drawings of the eggs as well as life history information.

Wikipedia: Mermithidae

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Robin Rosetta

Page last modified 5/29/14


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