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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.09.037 Byline: Sylvain Dubey (a), Gregory P. Brown (a), Thomas Madsen (b), Richard Shine (a) Abstract: Information on the phenotypic correlates of male reproductive success can provide important insights into the operation of sexual selection, and the nature of evolutionary forces on phenotypic traits such as male body size. We combined results from a long-term mark-recapture field study with genetic analyses for identifying paternity of offspring to quantify male reproductive success in a colubrid snake species from tropical Australia. Because previous work has shown that male slatey-grey snakes, Stegonotus cucullatus, attain larger body sizes than do conspecific females, we predicted that larger males would have higher reproductive success. Our paternity assignments of 219 offspring (24 clutches) supported this prediction: larger males fathered more offspring, not because they obtained more matings, but because they fathered a higher proportion of offspring within the clutches to which they did contribute. Multiple paternity was common (mean of 2.3 fathers per clutch, range 1-5). Our results demonstrate the utility of molecular approaches to clarify mating systems in field populations of snakes, and suggest that the evolution of extreme male-biased sexual size dimorphism in this species is attributable to enhanced reproductive success afforded by larger body size in males. Author Affiliation: (a) School of Biological Sciences, University of Sydney, Australia (b) School of Biological Sciences, University of Wollongong, Australia Article History: Received 19 June 2008; Revised 9 July 2008; Accepted 30 September 2008 Article Note: (miscellaneous) MS. number: 08-00403R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2007.10.011 Byline: Haley Bowcock, Gregory P. Brown, Richard Shine Abstract: Successful reproduction often involves complex communication, but signalling capabilities frequently differ between the sexes. Research on sexual communication in anuran amphibians has focused heavily on the advertisement call made by reproductive males, with less attention paid to the release signal that males (and some females) give in response to misdirected attempts at amplexus. In the cane toad the release signal consists of a mechanical component (vibrations of the body wall, given by both sexes) as well as an auditory call (apparently given by males alone). We investigated the cane toad release signal to ask: (1) do females call in a manner similar to that of males but at a frequency inaudible to human ears? and (2) what stimuli (acoustic or otherwise) induce males to terminate amplexus? Analysis of calls over a wide (4-100a000Hz) frequency range confirmed that female toads are indeed mute. Acoustic playback experiments revealed that males were less likely to dismount if we prevented an otherwise vocal target animal from making a release call. However, adding a release call to an otherwise mute target did not initiate dismount. Instead, the cue eliciting male dismount appears to involve synchrony between the release call and some other factor (probably, vibration of the clasped animal). Sexual dimorphism in skin rugosity also may play a role in amplexus termination. Author Affiliation: School of Biological Sciences, University of Sydney, Australia Article History: Received 16 July 2007; Revised 15 September 2007; Accepted 11 October 2007 Article Note: (miscellaneous) MS. number: 9458R

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2005.01.002 Byline: Shawn E. Vincent, Richard Shine, Gregory P. Brown Abstract: Theoretical models predict that modalities of prey detection depend upon foraging modes: ambush foragers will rely on visual cues to launch a strike whereas active searchers will use chemical cues to locate prey. Testing this prediction is hampered by phylogenetic conservatism; ideally, we need to compare closely related animals that differ in foraging mode. Aquatic filesnakes from tropical Australia offer a unique opportunity of this kind, because female filesnakes ambush large fish in deep water whereas male filesnakes search actively for smaller fish in shallow water. We exposed freshly captured filesnakes to artificial prey items providing visual and/or chemical cues and measured tongue-flick rates and feeding responses of the snakes. Males responded most intensely to fish scent, regardless of movement, whereas females responded strongly to movement. Thus, our data provide the first intraspecific (sex-based) evidence for a functional relationship between foraging mode and the types of cues used for prey detection. Author Affiliation: (*) Department of Ecology & Evolutionary Biology, Tulane University, U.S.A. (a ) School of Biological Sciences, University of Sydney, Australia Article History: Received 10 August 2004; Revised 28 October 2004; Accepted 4 January 2005 Article Note: (miscellaneous) MS. number: A9965