STABILIZING OR DIRECTIONAL SELECTION IN SIGNALING SYSTEMS - INVESTIGATIONS IN A POPULATION OF PAINTED REED FROGS, HYPEROLIUS MAMZORATRCS

Numerous studies in sexual selection have been interpreted as showing that components of the signalling system involved in mating are under strong directional selection due to female preferences for elaborate t raits. Conversely the recognition concept of species predicts strong s tabilizing selection on the specific-mate recognition system. We docum ent directional preferences in a population of the African painted ree d frog, Hyperolius marmoratus, in two-choice phonotaxis experiments, u tilizing synthesized calls. Females failed to respond consistently to population mean values of specific-mate recognition system signal comp onents in choice experiments presenting mean and extreme value stimuli . Even the least-preferred extremes of coupled signal components were still effective in eliciting phonotactic responses. Our results provid e no evidence for stabilizing selection within the tested range. Howev er there is also no evidence an open-ended directional preference span ning the natural range of male stimuli. The claims of the recognition concept are examined, We believe that it is incorrect to argue whether or nor the recognition concept is 'correct'. Rather, it provides an e xplicit null hypothesis. Studies in sexual selection are concerned wit h instances in which the assumptions of the recognition model are viol ated (e.g. where males signal variation in the benefits that they prov ide males). Understanding this issue should reduce the amount of confu sion in the literature, and clarify our objectives when it comes to in vestigating the selective forces manifest in signalling systems.