Mehdinema alii		Contents		Rev: 08/24/2026
		Classification		Biology and Ecology
		Morphology and Anatomy		Life Cycle
Return to Mehdinema Menu		Economic Importance		Ecosystem Functions and Services
		Distribution		Management
Return to Mehdinematidae Menu		Feeding		References
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Classification:

Chromadorea

Chromadoria

Rhabditina

            Diplogastroidea

Mehdinematidae

                  

Mehdinema alii Farooqui, 1967

Type species of the genus

    Synonyms:
      

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Morphology and Anatomy:

• Cuticle covered with dense, posteriorly-directed spines from head to mid-body then become less frequent and disappear.
• Lateral fields conceled by spines anteriorly but become visible at mid-body with  3 incisures
• Lip region has a pair of liplets and is surrounded by 6 setiform labial papillae; 2 circular amphid openings dorsosublaterally.
• Stoma tubular extending about 16% of esophagus length with large anteriorly and  a flattened, dorsal denticle posteriorly. DEG opens through the denticle.
• Esophagus proper with muscular procorpus, valvate muscular metacorpus, and valveless, only slightly muscular postcorpus.
• Excretory pore posterioe to esophago-intestinal junction.

Mehdinema alii (A) Adult male, entire specimen. (B) Adult female, entire specimen. (C) Female anterior end, lateral view. (D) Female stoma, lateral view. (E) Female vulva, lateral view. (F) Female tail, lateral view. Drawing from Luong et al., 1999

Females: Amphidelphic with reflexed ovaries. Vulva at mid-body, with protruding lips with a knoblike projection on the anterior lip Ovoviviparous,  both eggs and juveniles present in the uterus Female tail is approximately 7.5-10 tx abr width at the anus, attenuates gradually to a furcated tip Males Shorter than female Monorchic, testis ventral to intestine.  A cuticular flap is anterior to the cloacal opening   1 pair of sublateral precloacal genital papillae located asymmetrically on either side of the body, 1 small mid ventral genital papilla located on the anterior cloacal lip, 2 pairs of postcloacal papillae that lie asymmetrically on either side of the protruding gubernaculum ;  3 dome-shaped caudal papillae arranged asymmetrically Spicules paired, equal length, arcuate, needle-like, and apparently fused at the tip Gubernaculum complex , an arcuate apophysis terminating in a ventrally directed, bifid cuticularized ptrocess. Tail tightly coiled Ref : Luong et al., 1999

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

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Distribution:

The host, cricket, G. sigillatus is distributed worldwide throughout the tropics. It has been recorded from Australia, Cuba, Mexico, and Florida., Southern California and Arizona, USA. The introduced tropical insect has adapted to more arid conditions.

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Economic Importance:

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Feeding:

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Biology and Ecology:

The host cricket has a polygamous mating behavior in which male crickets attract females by through acoustic signals. Mating females receive a nutrient-rich spermatophylax, attached to a sperm-containing ampulla. The ampulla is removed after the spermatophylax is consumed. Females mate with multiple partners until enough sperm is obtained to fertilize available eggs

Infection appears to be male-biased. 75% of adult male crickets were infected but only 13% of females. Infection intensity was greater in male than in female crickets.

Most nematode infections in male crickets were in the hind gut with 25% in the genital chamber. Females had a low prevalence of nematodes in the hindgut but the majority of infected females had dauer juveniles (presumably the infective stage) in the genital chamber, suggesting sexual transmission..

Thesex-biased infection may be a direct consequence of the sexual (Luong et al., 2000),  The transmission mechanism implies behavioral synchronization with the host; presumably resulting from a long coevolutionary relationship.

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Life Cycle:

Dauer juveniles are a survival and infectice stage. Juveniles are transmitted sexually from males to females.  Adult female crickets harboring infective dauers subsequently transfer the nematode to their next mates. (Luong et al., 2000).

Ecophysiological Parameters:

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Ecosystem Functions and Services:

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Management:

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References:

Farooqui, M. N. 1967. On a new Mehdinematidae fam. nov. from Gryllus domesticus. Zoologischer Anzeiger 178: 322-326.

Luong, L.T., Platzer, E.G., Zuk, M., Giblin-Davis, R.M. 2000. Venereal worms: sexually transmitted nematodes in the decorated cricket. J. Parasitology 86:471-477.

Luong, L.T., Platzer, E.G., De Ley, P., Thomas, W.K. 1999. Morphological, molecular and biological characterization of Mehdinema alii (Nematode: Diplogasteriad) from the decorated cricket (Gryllodes sigillatus). J. Parasitol. 85:1053-1064.