Individual variability in the swimming behavior of the sub-tropical copepod Oncaea venusta (Copepoda: Poecilostomatoida)

The swimming behavior of males and females of the seldom studied sub-tropical copepod Oncaea venusta was studied using scale-dependent (swimming speed and net-to-gross displacement ratio) and scale-independent (fractal dimension) metrics. The scale-dependent metrics were characterized by: (1) a considerable intra- and inter-individual variability that prevented the identification of any specific behavior and (2) a strong dependence on the number of data points available in each individual path. Conversely, the scale-independent metric (fractal dimensional) resolved reduced intra- and inter-individual variability and independence from the length of the swimming paths, leading to the identification of 4 groups of distinct swimming patterns. While additional behavioral experiments are needed to ensure the relevance and the generality of the present results, behavioral fractal analysis nevertheless demonstrates a promising ability to elucidate the complexity of zooplankton behavior.