Capture efficiency of the freshwater prawn Palaemonetes argentinus (Nobili 1901) on the Culex pipiens s.l. (Linnaeus 1758) mosquitoes larvae.

Abstract

The predation consists of a chain of events divided in three phases: encounter, capture and ingestion. We filmed the prawn Palaemonetes argentinus depredate on mosquitoes larvae (Culex pipiens s.l.) in aquaria, watching an increment in the swimming activity of prawns then to recognize the movement of the larvae by mechanoreceptors. The encounters of prey demand in the aquaria with small prawns 13.9 ± 9.39 seconds, in the aquarium with big prawns 26.6 ± 23.47 seconds, and in the pools with mixed prawns 17.9 ± 16.32 seconds. The attacks were more efficiently in small prawn (73%) that in big prawn (44%), maybe because the small prawns are better swimmers than big ones. The capture of prey was made with the second pereiopods and rapidly will be carried to its cephalic appendices. These larvae are preferment eaten by the cephalic region (79.33 %) and in this manner the prawns neutralized its possible escapes. The time utilized into manipulation depends of the larvae number depredated. In general, the time to eat the mosquitoes larvae is longer in the small prawns (91.0 ± 90.3 seconds) that the big prawns (25.0 ± 27.9 seconds).