Implications of animalfluid interactions for the feeding behavior of Lychnorhiza lucerna

Abstract

Swimming and feeding are coupled features of Scyphozoa medusae. The contractions of the bell, which provide the forward motion, also produce flows towards the feeding surfaces at the oral arms and tentacles. Patterns of swimming vary among the scyphozoan groups. Rhizostomeae jellyfish are conspicuous components of tropical and subtropical coastal areas with distinguishable swimming patterns. They are robust swimmers, with high pulsation frequencies and strong marginal flows. Besides the highly modified morphology of the feeding structures, swimming traits may also influence the animal´s ecological role by affecting feeding rates, prey capture and selectivity. This BEPE project requests a three month training internship at the Marine Biological Laboratory, Woods Hole, US. My goal is to focus on learning video techniques and methods of analysis applied to studies of animal-fluid interactions. High frequency videos (250-1000 frames per second) of the Rhizostomeae medusae L. lucerna, which is the target species of my Ph.D. research, were recorded during the visit of Dr. John Costello to the laboratories of CEBIMar-USP. These videos will be analyzed in order to describe: i- swimming kinematics; ii- interactions of swimming vortex with oral arms; and iii- prey capture events. Digital particle image velocimetry (DPIV) techniques will be applied to measure the water flow velocity surrounding the animal. These results will be compared to field data on diet and prey selectivity (already performed during the Ph.D.), thus extending knowledge about the mechanical basis of feeding patterns of Rhizostomeae medusae. (AU)