1. Sexual dimorphism of the cuticle and body-wall muscle in free-living mycophagous nematodes
- Author
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Ekino, T., Yoshiga, T., Takeuchi-Kaneko, Y., Ichihara, Y., and Kanzaki, N.
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Nematoda ,Proteins ,Zoology and wildlife conservation - Abstract
Sexual dimorphism in motility-related traits is widespread among animals, including several species of Nematoda. However, no study has examined motility-related structural components and compared them between sexes. We examined the motility-related components in four species: Bursaphelenchus conicaudatus Kanzaki, Tsuda and Futai, 2000; Bursaphelenchus rainulfi Braasch and Burgermeister, 2002; Bursaphelenchus doui Braasch, Gu, Burgermeister and Zhang, 2005; Parasitaphelenchus costati Kanzaki, Ekino, Ide, Masuya and Degawa, 2018. We measured the structure and amount of cuticle and body-wall muscles and estimated their relationship to body diameter or total cross-sectional area. Although no structural differences were observed in muscle, the relevant muscle area of B. doui and P. costati was significantly smaller in females than in males. This difference was greatest in P. costati. In all but B. doui, the relative cuticle thickness was significantly smaller in females than in males. Furthermore, only P. costati females had no striated basal zones in their cuticles; these are thought to be cross-linked proteins that provide strength to nematode cuticle during body movement. These results indicate that sexual dimorphism in motility-related structural components is present in P. costati and that females invest less energy in the components than do males. Key words: Bursaphelenchus conicaudatus, Bursaphelenchus doui, Bursaphelenchus rainulfi, cuticle structure, entomophilic nematode, motility, muscles, Parasitaphelenchus costati, transmission electron microscopy. Un dimorphisme sexuel de caracteres associes a la motilite est repandu chez les animaux, notamment chez plusieurs especes de nematodes. Aucune etude ne s'est toutefois penchee sur les elements structuraux associes a la motilite, ni n'en a fait une comparaison entre les sexes. Nous avons examine les elements associes a la motilite chez les quatre especes suivantes: Bursaphelenchus conicaudatus Kanzaki, Tsuda et Futai, 2000; Bursaphelenchus rainulfi Braasch et Burgermeister, 2002; Bursaphelenchus doui Braasch, Gu, Burgermeister et Zhang, 2005; Parasitaphelenchus costati Kanzaki, Ekino, Ide, Masuya et Degawa, 2018. Nous avons mesure la structure et la quantite de cuticule et de muscles de la paroi corporelle et estime leur relation avec le diametre du corps ou l'aire totale de sa coupe transversale. Bien qu'aucune difference structurale n'ait ete observee dans les muscles, l'aire des muscles pertinents de B. doui et P. costati etait significativement plus petite chez les femelles que chez les mâles. Cette difference est la plus grande chez P. costati. Chez toutes les especes sauf B. doui, l'epaisseur relative de la cuticule etait significativement plus faible chez les femelles que chez les mâles. En outre, seules les femelles de P. costati ne presentaient pas de zones basales striees dans leurs cuticules; ces elements seraient des proteines reticulees qui conferent de la force a la cuticule des nematodes durant des mouvements du corps. Ces resultats indiquent qu'un dimorphisme sexuel d'elements structuraux associes a la motilite est present chez P. costati et que les femelles investissent moins d'energie dans ces elements que les mâles. [Traduit par la Redaction] Mots-cles : Bursaphelenchus conicaudatus, Bursaphelenchus doui, Bursaphelenchus rainulfi, structure de la cuticule, nematode entomophile, motilite, muscles, Parasitaphelenchus costati, microscopie electronique a transmission., Introduction Polymorphism is widespread throughout the animal kingdom, and studies of polymorphism have played an important role in understanding life-history evolution and the physiological basis of adaptation (Zera and Denno [...]
- Published
- 2019
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