Skip to main content Accessibility help

Infrapopulations of Procamallanus elatensis Fusco & Overstreet, 1979 (Nematoda: Camallanidae) in the rabbitfish Siganus rivulatus (Teleostei, Siganidae) from the Saudi coast of the Red Sea

  • Mohammed O. Al-Jahdali (a1)

Factors regulating gastrointestinal nematode infrapopulations are to a great extent density-dependent. Here, 23 natural infrapopulations (41–281 individuals) of the viviparous nematode Procamallanus elatensis (Camallanidae) from the fish Siganus rivulatus were found distributed in a well-defined fundamental niche (posterior 55% of the intestine). Immature worms were mostly found in the anterior third of this niche, while mature worms were found in aggregations posterior to them and followed by gravid females in the posterior 20% of the intestine. This distribution strongly suggests that worms migrate towards the posterior intestine while they mature, copulate and reproduce. In small infrapopulations, the sex ratios were distinctly female-biased and the number of gravid females was low. In large infrapopulations, the sex ratios were distinctly male-biased and the number of gravid females was high. However, the mean lengths of both immature males and females and mature females decreased dramatically as the infrapopulation size increased, while those of mature males increased significantly. These results strongly suggest intraspecific competition and density-dependent regulation of mean worm length, and the increase in the mean length of mature males strongly suggests intense sexual selection and competition between mature males. Production of larvae by female worms decreased significantly as the infrapopulation size increased, suggesting a density-dependent reduction in female worm fertility. The results are statistically significant and strongly suggest that infrapopulation self-regulation is through density-dependent mechanisms, in which development of immature worms, infrapopulation size, sex ratio, sexual selection and carrying capacity of the fundamental niche play essential roles in shaping and regulating the infrapopulations.

Corresponding author
* E-mail:
Hide All
Andersson, M. (1994) Sexual selection. 1st edn.624 pp. Princeton, Princeton University Press.
Ashworth, S.T. & Kennedy, C.R. (1999) Density-dependent effects on Anguillicola crassus (Nematoda) within its European eel definitive host. Parasitology 118, 289296.
Barse, A.M., Mcguire, S.A., Vinores, M.A., Elerman, L.E. & Weeder, J.A. (2001) The swimbladder nematode Anguillicola crassus in American eels (Anguilla rostrata) from middle and upper regions of Chesapeake Bay. Journal of Parasitology 87, 13661370.
Borgsteede, F.H.M. & Hendriks, J. (1979) Experimental infections with Cooperia oncophora (Railliet, 1918) in calves: results of single infections with two graded dose levels of larvae. Parasitology 78, 331342.
Bush, A.O., Lafferty, K.D., Lotz, J.M. & Shostak, A.W. (1997) Parasitology meets ecology on its own terms: Margolis et al. revisited. Journal of Parasitology 83, 575583.
Dezfuli, B.S., Volponi, S., Beltrami, I. & Poulin, R. (2002) Intra- and interspecific density-dependent effects on growth in helminth parasites of the cormorant. Phalacrocorax carbo sinensis. Parasitology 124, 537544.
Dunn, A.M. (1965) The gastro-intestinal helminths of wild ruminants in Britain. Parasitology 55, 739745.
Froese, R. & Pauly, D. (2004/2010) FishBase. World Wide Web electronic publication. Available, version 04/2010 (accessed May 2010).
Fusco, A.C. & Overstreet, R.M. (1979) Two camallanid nematodes from Red Sea fishes including Procamallanus elatensis sp. nov. from siganids. Journal of Natural History 13, 3540.
Ghiselin, M.T. (1974) The economy of nature and the evolution of sex. 2nd edn.364 pp. Berkeley, California, University of California Press.
Guyatt, H.L. & Bundy, D.A.P. (1993) Estimation of intestinal nematode prevalence: influence of parasite mating patterns. Parasitology 107, 99106.
Hassanine, R.M. & Al-Jahdali, M.O. (2008) Intraspecific density-dependent effects on growth and fecundity of Diplosentis nudus (Harada, 1938) Pichelin et Cribb, 2001 (Acanthocephala: Cavisomidae). Acta Parasitologica 53, 289295.
Haukisalmi, V., Henttonen, H. & Vikman, P. (1996) Variability of sex ratio, mating probability and egg production in an intestinal nematode in its fluctuating host population. International Journal for Parasitology 26, 755764.
Irvine, R.J., Stien, A., Dallas, J.F., Halvorsen, O., Langvatn, R. & Albon, S.D. (2001) Contrasting regulation of fecundity in two abomasal nematodes of Svalbard reindeer (Rangifer tarandus platyrhynchus). Parasitology 122, 673681.
Keymer, A.E. (1982) Density-dependent mechanisms in the regulation of intestinal helminth populations. Parasitology 84, 573587.
Marcogliese, D.J. (1997) Fecundity of sealworm (Pseudoterranova decipiens) infecting grey seals (Halichoerus grypus) in the Gulf of St. Lawrence, Canada: lack of density-dependent effects. International Journal for Parasitology 27, 14011409.
May, R.M. & Woolhouse, M.E.J. (1993) Biased sex-ratios and parasite mating probabilities. Parasitology 107, 287295.
Morand, S. & Hugot, J-P. (1998) Sexual size dimorphism in parasitic oxyurid nematodes. Biological Journal of the Linnean Society 64, 397410.
Moravec, F., Menodoza-Franco, E., Vargas-Vázquez, J. & Vivas-Rodríguez, C. (1995) Studies on the development of Procamallanus (Spirocamallanus) rebecae (Nematoda: Camallanidae) a parasite of cichlid fishes in Mexico. Folia Parasitologica 42, 281292.
Mössinger, J. & Wenk, P. (1986) Fecundity of Litomosoides carinii (Nematoda, Filarioidea) in vivo and in vitro. Zeitschrift für Parasitenkunde 72, 121131.
Poulin, R. (1997a) Population abundance and sex ratio in dioecious helminth parasites. Oecologia 111, 375380.
Poulin, R. (1997b) Covariation of sexual size dimorphism and adult sex ratio in parasitic nematodes. Biological Journal of the Linnean Society 62, 567580.
Poulin, R. (2001) Interactions between species and the structure of helminth communities. Parasitology 122, S3S11.
Poulin, R. (2006) Evolutionary ecology of parasites. 2nd edn.332 pp. Princeton, Princeton University Press.
Randall, J.E. (1983) Red Sea reef fishes. 2nd edn.192 pp. London, IMMEL Publishing.
Richards, D.T. & Lewis, J.W. (2001) Fecundity and egg output by Toxocara canis in the red fox, Vulpes vulpes. Journal of Helminthology 75, 157164.
Roche, M. & Patrzek, D. (1966) The female to male ratio (FMR) in hookworm. Journal of Parasitology 52, 117121.
Seidenberg, A.J., Kelly, P.C., Lubin, E.R. & Ngton, J.D. (1974) Helminths of the cotton rat in southern Virginia, with comments on the sex ratios of parasitic nematode populations. The American Midland Naturalist 92, 320326.
Shostak, A.W. & Scott, M.E. (1993) Detection of density-dependent growth and fecundity of helminthes in natural infections. Parasitology 106, 527539.
Sinniah, B. & Subramaniam, K. (1991) Factors influencing the egg production of Ascaris lumbricoides: relationship to weight, length and diameter of worms. Journal of Helminthology 65, 141147.
Stien, A., Dallimer, M., Irvine, R.J., Halvorsen, O., Langvatn, R., Albon, S.D. & Dallas, J.F. (2005) Sex ratio variation in gastrointestinal nematodes of Svalbard reindeer; density dependence and implications for estimates of species composition. Parasitology 130, 99107.
Szalai, A.J. & Dick, T.A. (1989) Differences in numbers and inequalities in mass and fecundity during the egg-producing period for Raphidascaris acus (Nematoda: Anisakidae). Parasitology 98, 483489.
Tingley, G.A. & Anderson, R.M. (1986) Environmental sex determination and density-dependent population regulation in the entomogenous nematode Romanomermis culicivorax. Parasitology 92, 431449.
Watson, H., Lee, D.L. & Hudson, P.J. (1988) Primary and secondary infections of the domestic chicken with Trichostrongylus tenuis (Nematoda), a parasite of red grouse, with observations on the effect on the caecal mucosa. Parasitology 97, 8999.
West Eberhard, M.J. (1983) Sexual selection, social competition, and speciation. Quarterly Review of Biology 58, 155183.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Helminthology
  • ISSN: 0022-149X
  • EISSN: 1475-2697
  • URL: /core/journals/journal-of-helminthology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed