Data/hora: 21/06/2024 19:55:14

Biblioteca(s): | Embrapa Amazônia Ocidental.
Data corrente: | 09/11/2010
Data da última atualização: | 08/04/2021
Autoria: | FERNANDES, C. C.; SMITH, G. T.; PODOS, J.; NOGUEIRA, A.; INOUE, L. A. K. A.; AKAMA, A.; HO, W. W.; ALVES-GOMES, J.
Afiliação: | Cristina Cox Fernandes, University of Massachusetts; G. Troy Smith, Indiana University; Jeffrey Podos, University of Massachusetts; Adília Nogueira, INPA; LUIS ANTONIO KIOSHI AOKI INOUE, CPAA; Alberto Akama, Universidade Federal do Tocantins; Winnie W. Ho, Indiana University; José Alves-Gomes, INPA.
Título: | Hormonal and behavioral correlates of morphological variation in an Amazonian electric fish (Sternarchogiton nattereri: Apteronotidae).
Ano de publicação: | 2010
Fonte/Imprenta: | Hormones and Behavior 58, n. 4, p. 660-668, 2010.
Idioma: | Inglês
Conteúdo: | The weakly electric fish from the main channel of the Amazon river, Sternarchogiton nattereri, offers a striking case of morphological variation. Females and most males are toothless, or present only few minute teeth on the mandible, whereas some males exhibit exaggerated, spike-like teeth that project externally from the snout and chin. Androgens are known to influence the expression of sexually dimorphic traits, and might be involved in tooth emergence. In this study we assess the relationship in S. nattereri between morphological variation, 11 ketotestosterone (11-KT) and testosterone (T). We also examine relationships of morphology and androgen levels with electric organ discharge (EOD) frequency, reproductive condition, and seasonality. Our main finding is that male morph categories differed significantly in plasma concentrations of 11-KT, with toothed males showing higher levels of 11-KT than toothless males. By contrast, we did not detect statistical differences in T levels among male morph categories. Reproductive condition, as measured by gonadosomatic indexes (GSI), differed across two sample years, increased as the season progressed, and was higher in toothed males than in non-toothed males. EOD frequency was higher in toothed males than in either toothless males or females. Taken together, our findings suggest that S. nattereri male sexual characters are regulated by 11-KT levels, and that both morphology and androgens interact with reproductive condition and EOD frequency in ways that vary within and across reproductive seasons.
Palavras-Chave: | Morfologia; Variação comportamental; Variação morfológica.
Thesagro: | Peixe Elétrico.
Categoria do assunto: | --
Registro original: | Embrapa Amazônia Ocidental (CPAA)
Exemplares: | CPAA - (22993-1) - UPC - AP - PP - S8733 -  - S8733 - DIS