Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2009.03.006 Byline: Albert F.H. Ros (a), Teresa Fagundes (a), Rui F. Oliveira (a)(b) Abstract: In maximizing reproductive success, individuals face a trade-off between parental care for their current offspring and investing in androgen-dependent sexual traits to produce further offspring. It has thus been proposed that parental effort would suppress androgen levels. Here, we studied parental effort by manipulating brood size in the peacock blenny, Salaria pavo, a littoral fish species in which males show long periods of paternal care. We focused on the effects of brood size on female spawning rate (measured as number of eggs received in the nest by focal males) and androgen levels. We found a positive linear relationship between brood size and the number of eggs received subsequently. Accordingly, spawning rate increased for males with experimentally enlarged broods while it decreased for males in which brood size was reduced. However, over a longer time interval, brood sizes of both treatments returned to the nonmanipulated brood size, suggesting an effect of additional factors such as male quality. Brood size did not show the expected negative relationship with levels of testosterone and 11-ketotestosterone. On the contrary, testosterone levels were positively correlated with brood size. However, in agreement with the prediction, changes in the level of parental care by manipulation of brood size showed an inverse relationship with testosterone levels. As with brood size, given time, testosterone levels tended to return to nonmanipulated levels. Such changes suggest that males adjust their brood size to an individual value through androgen modulation of courtship or other traits influencing female spawning rate. Author Affiliation: (a) Unidade de Investigacao em Eco-Etologia, Instituto Superior de Psicologia AplicadaPortugal (b) Champalimaud Neuroscience Programme, Instituto Gulbenkian de CiA*ncia, Portugal Article History: Received 5 March 2008; Revised 27 June 2008; Accepted 16 March 2009 Article Note: (miscellaneous) MS. number: 08-00148R