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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

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.04.016 Byline: Molly E. Cummings, Joana M. Jordao, Thomas W. Cronin, Rui F. Oliveira Abstract: We investigated the visual ecology of the coloration of the eastern Atlantic fiddler crab, Uca tangeri, with particular attention to predator (e.g. avian) and conspecific vision. Spectral reflectance measurements were made on different body parts used in possible intraspecific communication as well as background habitats including crab-made materials (e.g. mudballs). Avian-based and crab-based visual models were used to obtain different estimates of crab conspicuousness to potential predators and conspecifics. We found that male body parts (except for dorsal carapace) were significantly more conspicuous to conspecific viewers than female equivalent body parts, and showed greater within-body contrast estimates. Moreover, male major claw areas differed in reflectance properties, producing variation in conspicuousness that fit signalling predictions: areas visible during claw-waving events were most conspicuous against the background sky, whereas areas visible in nonwaving positions were more conspicuous against substrate backgrounds. For avian vision, sexually dimorphic coloration results in males being generally more conspicuous than females (in terms of brightness contrast) against all backgrounds, however, there was no sexual dimorphic conspicuousness of carapace coloration. Furthermore, one of the most conspicuous features of both male and female crabs is an area that is likely to be more visible to crabs (mouthparts) than to avian predators from above. While conspicuousness varies with background, the most conspicuous background for male signalling parts (major claw) is dark mudballs, suggesting that males may increase the conspicuousness of their signals by modifying their signalling environment. Author Affiliation: (a) Section of Integrative Biology, University of Texas at Austin, U.S.A. (a ) Unidade de Investigacao em Eco-Etologia, Instituto Superior de Psicologia Aplicada, Lisboa, Portugal (a ) Department of Biology, University of Maryland at Baltimore County, U.S.A. Article History: Received 19 June 2006; Revised 24 September 2006; Accepted 9 April 2007 Article Note: (miscellaneous) MS. number: A10479R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2005.04.014 Byline: Katharina Hirschenhauser, Rui F. Oliveira Abstract: The challenge hypothesis (Wingfield et al. 1990, American Naturalist, 136, 829-846) predicts varying androgen responses to mating, breeding or territorial behaviour in avian males. At the interspecific level, the highest androgen responsiveness has been observed in males from monogamous species with paternal incubation, and the lowest in males from promiscuous, nonpaternal species. Studies of a number of vertebrate species have discussed the extension of the challenge hypothesis predictions to nonavian vertebrates, but a general 'vertebrate consensus' has not been achieved. For this quantitative review we included data from all vertebrate species available in the literature into several meta-analyses. We distinguished between the effects of androgens on sexual, aggressive and paternal behaviour and the effects of behaviour on androgen levels and compared these effects between taxa, mating systems and types of parental care. We observed large variations between taxa in all data sets. Nevertheless, at the vertebrate level the challenge hypothesis predictions originating from the avian literature were confirmed for the modulation of androgen responsiveness (1) to sexual behaviour by paternal care but not by mating system, and (2) to paternal behaviour by mating system but not the degree of paternal care. In contrast, our results provide (3) no support for the predicted modulation of androgen levels in response to agonistic interactions by mating and parental care system at the vertebrate level. Furthermore, our meta-analyses suggest that the effects of exogenous testosterone on sexual and agonistic behaviour, as a rule of thumb, may be expected to be larger in nonpaternal than in paternal systems. Author Affiliation: Unidade de Investigacao em Eco-Etologia, ISPA, Portugal Article History: Received 24 September 2004; Revised 5 November 2004; Accepted 10 April 2005 Article Note: (miscellaneous) MS. number : RV54

Visual communication in the marine fish, Salaria pavo, was studied using video playbacks.

Both male and female European fiddler crab, Uca tangeri, produce mudballs. Among females this is merely a by-product of nest digging but among males, mudballs serve two other functions. Experimental removal of mudballs increased aggression among neighboring males while placing mudballs next to crab dummies encouraged females to approach and enter the burrows. These results suggest that mudballing behavior serves to reduce competition among males and attract female conspecifics.

The ecological modulation affects sex roles in a natural population of the blenniid fish, Salaria pavo. The female initiation of mating predominates over male intra-sexual competition, active courtship and developed epigamic characters in males. More than one female of S. pavo comes to the nest and each female mates with different males during the breeding season. The males are selective in admitting the females to the nest. The ability of females to spawn determines the male courtship behavior for the nest sites.