Tinbergen suggested there are four major aims or questions in ethology. All of these contribute to the larger single question of why animals behave as they do. Here, I emphasise one aim, to understand the evolution of behaviour. Using studies of sexual communication in túngara frogs (Physalaemus pustulosus) I attempt to illustrate how an analysis of the past evolution of behaviour can contribute to our understanding of its current function and the details of the mechanisms guiding it. I argue that integration of Tinbergen's four questions not only give us a more complete understanding of the biology of behaviour, it might be necessary to give us a correct understanding.
Michael A. Ryan
Michael A. Ryan
Alexander Baugh and Michael Ryan
In acoustically advertising anurans the male courtship call elicits species-typical responses from conspecifics – usually phonotactic approach and mate choice in gravid females and an evoked vocal response in adult males. Males in several species, however, are also known to perform phonotaxis, sometimes with the same acoustic preferences as females. Female túngara frogs are known to update their phonotactic approach as male advertisement signals change dynamically in attractiveness. Here we show that males also perform such temporal updating during phonotaxis in response to dynamic playbacks. While males exhibit slower phonotactic approaches than females, their responsiveness to dynamic changes in call complexity does not differ significantly compared to females. These results demonstrate that males are sensitive to the location of preferred call types on a moment-to-moment basis and suggest that similarities between male and female sexual behaviour in anurans might often be overlooked. We suggest that anuran phonotaxis is more widespread and serves different functions in reproductive females and males. Lastly, these temporal updating results suggest that male frogs are highly selective about site selection in a chorus.
Edited by Michael A. Ryan
Contributors are: Roland Betancourt, Robert Boenig, Richard K. Emmerson, Ernst Hintz, László Hubbes, Hiram Kümper, Natalie Latteri, Thomas Long, Katherine Olson, Kevin Poole, Matthias Riedl, Michael A. Ryan
Michael Ryan, Ryan McKnab and Ingo Schlupp
Females of many species receive male attention that reflects a conflict between the sexes over reproduction. Here we demonstrate that female sailfin mollies (Poecilia latipinna) suffer such a cost via a reduction of their feeding time in the presence of males. Female sailfin mollies spend significantly more time feeding when accompanied by an Amazon molly (P.formosa) or a sailfin molly female than when accompanied by a male sailfin molly. Furthermore, we show that male sexual harassment is size dependent and that small males impose a greater cost on females.