Pre-copulatory swimming behavior of Leptodiaptomus ashlandi (Copepoda: Calanoida): A fractal approach

Abstract

Mating behaviour is an emerging topic in the study of copepod ecology, having important consequences at both individual and population levels. Mate-finding has been shown to depend upon the perception of cues released by the conspecific, as well as on the swimming behaviour of both the male and the female. In order to understand the differences in the strategies adopted in the pre-copulatory phase by males and females, we analysed the swimming tracks of the freshwater calanoid Leptodiaptomus ashlandi. The three-dimensional trajectories described by males and females have been analysed in terms of their three-dimensional fractal dimension D3D, a parameter which can synthetically but appropriately characterize the degree of contortion of a three-dimensional path. D3D values for L. ashlandi males during the pre-detection phase are higher than the corresponding ones for females, indicating that the male explores more extended volumes of fluid, thus increasing the probability of encountering a female. © The Author 2006.