Abstract
The aim of the present study was to determine the life-cycle of Narapa bonettoi in the main channel of the Middle Paraná River. The average density varied between 17 and 624 ind. sample−1. The spatial distribution was contagious with a higher degree of aggregation during the first months of the observed cycle, than during the last months. Mature specimens were more abundant in September 1985–86, resulting in greater breeding activity in early summer, when there was a large population increase. Two reproductive strategies were observed: asexual and sexual. After breeding, worms undergo a resorption process of their reproductive organs, returning to a non-sexual condition. Narapa bonettoi probably uses asexual reproduction as an adaptative strategy, because cocoon development will be affected by environmental factors such as the drift in the Paraná River which is highly erodable. Population growth was rapid during the first four months and then stabilized.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bertolid de Pomer, H., C. Copes, I. Ezcurra de Drago & M. Marchese, 1986. Caracteristicas limnologicas del rio Parana y sus principales tributarios en el tramo GoyaDiamante. Los sedimentos y su fauna. Rev. Asoc. Cienc. Nat. Litoral 17: 79–97.
Elliott, J. M., 1977. Some methods for statistical analyses of samples of benthic invertebrates. (3nd edn), Sci. Publ. Freshwat. Biol. Assoc., Ambleside 25, 160 pp.
Ezcurra de Drago, L, 1980. Campana limnologica ‘Keratella I' en el rio Parana Medio: Complejo bentonico del rio y ambientes leniticos asociados. Ecologiá 4: 89–101.
Learner, M. A., G. Lochhead & B. D. Hughes, 1978. A review of the biology of British Naididae (Oligochaeta) with emphasis on the lotic environments. Freshwat. Biol. 8: 357–375.
Loden, M., 1981. Reproductive ecology of Naididae (Oligochaeta). Hydrobiologia 83: 115–123.
Marchese, M., 1981. Contribución al conocimiento del complejo bentónico del río Paraná medio. Ecologia 6: 55–65.
Marchese, M., 1984. Estudios limnologicos en una seccíon transversal del tramo medio del río Paraná. XI: Zoobentos. Rev. Asoc. Cienc. Nat. Litoral 15: 157–174.
Marchese, M., 1987. The ecology of some benthic Oligochaeta from Paraná River, Argentina. Hydrobiologia 155: 209–214.
Marchese, M. & I. Ezcurra de Drago, 1983. Zoobentos de los principales tributarios del río Paraná medio en el tramo Goya-Diamante. Su relación con el cauce principal y cauces secundarios. Rev. Asoc. Cienc. Nat. Litoral 14: 97–107.
Marchese, M. & I. Ezcurra de Drago, 1992. Benthos of the lotic environments in the Middle Paraná River system. Transverse zonation. Hydrobiologia 237: 1–14.
Mehra, H. R., 1920. On the sexual phase in certain Indian Naididae. Proc. zool. Soc., London 31: 457–465.
Righi, G. & M. E. Varela, 1983. Narapa bonettoi, gen. nov., sp. nov. (Oligochaeta, Narapidae, Fam. nov.) de agua doce da Argentina. Rev. Asoc. Cienc. Nat. Litoral 14: 7–15.
Wetzel, R. G. & G. E. Likens, 1991. Limnological Analyses. 2nd Edition. Springer-Verlag, New York, 391 pp.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Marchese, M. Population dynamics of Narapa bonettoi Righi and Varela, 1983 (Oligochaeta: Narapidae) from the main channel of the Middle Paraná River, Argentina. Hydrobiologia 278, 303–308 (1994). https://doi.org/10.1007/BF00142339
Issue Date:
DOI: https://doi.org/10.1007/BF00142339