Density-dependent mate searching strategies of male woodfrogs

Abstract Individually marked male woodfrogs, Rana sylvatica , were monitored throughout the night in an unmanipulated aggregation and in an aggregation with artificially reduced density. Males were less active in the low density aggregation. Movement was modelled using a computer simulation that assumed that male movement patterns resulted from chance encounters between searching males. The model success-fully predicted the results observed at the low density, but was unable to predict those observed at the high density. This suggest that males may assess density and actively respond to it. A second result was that males in the low density aggregation were more likely to search for mates at the oviposition site, but males in the high density aggregation were more likely to search at the aggregation periphery. This change in behaviour is predicted by a simple evolutionarily stable strategy model.