X hits on this document

254 views

0 shares

0 downloads

0 comments

48 / 80

Reproductive aspects of the Jenynsia multidentata.

45

consent of female. The males take position along the female posterior side and try to introduce their gonopod into the female urogenital opening as fast and furtively as they can (Bisazza et al. 2000). The males expend a great part of their daily time in this activity. This behavior probably make them less careful (compared with females) regarding avoiding predator’s attacks by piscivorous fishes and birds. This differential behavior between genders could result in a higher male predation rate, resulting in larger numbers of females in the population (Magurran & Nowak 1991, Magurran & Seghers 1991). An alternative hypothesis could be associated with differences in capture of males and females by the fish gear (beach seine hauls) employed during our sampling. In this case, the males could be simply under captured due their smaller size, resulting in a higher ratio of females in the samples. More studies should be conducted in controlled conditions at the laboratory and in natural environment in order to test these hypotheses.

Acknowledgements

We are grateful to the Fundação de Amparo a Pesquisa Rio Grande do Sul – FAPERGS for the scholarship provided to the first author, to CNPq- PELD for the financial support in permanent and consume materials, to the staff od the Laboratório de Ictiologia (FURG) for the logistical support, to Kátia L. B. Andrade and Jamile C. Oliveira for their collaboration in preliminary processing of samples.

References Betito, R. 1984. Dinâmica da População de Jenynsia lineata (Cyprinodontiformes, Anablepidae) na restinga de Rio Grande, estuário da Lagoa dos Patos (RS-Brasil). MSc. Thesis, FURG, Rio Grande do Sul - Brasil. Bisazza, A., Manfredi, S. & Pilastro, A. 2000. Sexual competition, coercive mating and mate assessment in the one-sided livebearer, Jenynsia multidentata: Are they predictive of sexual dimorphism? Ethology, 106: 961-978. Chao, L. H., L. E. Pereira & J. P. Vieira. 1985. Estuarine fish community of the dos Patos lagoon, Brazil, p. 429-450. In: Yanez-

Arancibia,

A.

(Ed.).

Fish

community

ecology in estuaries and coastal lagoons: Towards an ecoystem integration. DR (R) UNAM Press, Mexico, 560 p.

Constantz, G. D. 1984. Sperm competition in poecilid fishes, p. 465–485. In: Smith, R. L. (Ed.). Sperm competition and the evolution of animal mating systems. Academic Press,

Orlando, 687 p.

Costa, C.S.B., U. Seeliger & P.G. Kinas. 1988. The effect of wind velocity and direction on the salinity regime in the lower Patos Lagoon estuary. Ciência e Cultura, 40: 909-912. Endler, J. A. 1995. Multiple-trait coevolution and environmental gradients in guppies. Trends in Ecology & Evolution, 10: 22-29. Farr, J. A. 1977. Male rarity or novelty, female choice behavior, and sexual selection in the guppy, Poecilia reticulata peters (Pisces: Poeciliidae). Evolution, 31: 162-168. Fontoura, N. F., Braun, A. S., Lewis, D. S. & Souto, G. D. B. 1994. Dinâmica populacional da ictiofauna da Lagoa Fortaleza, Cidreira, Rio Grande do Sul II. Jenynsia lineata (JENYNS, 1842) (Teleostei, Anablepidae). Biociência, 2: 75-78. Garcia, A. M., Vieira, J. P., Winemiller, K. O. & Raseira, M. B. 2004. Reproductive cycle and spatiotemporal variation in abundance of the one-sided livebearer Jenynsia multidentata, in Patos Lagoon, Brazil. Hydrobiologia, 515 (1-3): 39-48. Ghedotti, M. J. 1998. Phylogeny and classification of the anablepidae (Teleostei: Cyprinodontiformes), p. 561-582. In: Malabarba, L. R., Reis, R. E., Vari, R. P., Lucena, Z. M. S. & Lucena, C. A. S. (Eds.). Phylogeny and classification of neotropical fishes. EDIPUCRS, Porto Alegre, 603 p. Ghedotti, M. J. & Weitzman, S. H. 1996. A new species of Jenynsia (Cyprinodontiformes: Anablepidae) from Brazil with comments on the composition and taxonomy of de genus. Natural History Museum and Department of Systematcs and Ecology, 179: 1-25. Hamilton, M. A., Russo, R. C. & Thurston, R. V. 1977. Trimmed Spearmann-Karber method for estimating median lethal concentration in toxicity bioassays. Environmental Science Technology, 11 (7): 714-719. Mai, A. C. G., Garcia, A. M. & Vieira, J. P. 2005. Influência da salinidade no crescimento de

juvenis do

barrigudinho

Jenynsia

multidentata

Jenyns, 1842.

Revista

Brasileira de Zoologia, 22 (3): 780-783. Magurran, A. E. & Nowak, M. A. 1991. Another battle of the sexes – the consequences of sexual asymmetry in mating costs and predation risk in the Guppy, Poecilia- Reticulata. Proceedings of the Royal Society of London Series B-Biological Sciences, 246 (1315): 31-38.

Pan-American Journal of Aquatic Sciences (2007), 2 (1): 40-46

Document info
Document views254
Page views254
Page last viewedSun Dec 11 00:32:38 UTC 2016
Pages80
Paragraphs4377
Words44828

Comments