Cannibalistic behaviour of rock-pool copepods: An experimental approach for space, food and kinship

Abstract

Studies on cannibalism in harpacticoid copepods are restricted to predation on naupliar larvae in rock-pool harpacticoids of the genus Tigriopus. An earlier experimental study on the Mediterranean copepod Tigriopus fulvus indicated that females recognized their own larvae and preferentially preyed on nauplii other than their own. In a series of laboratory experiments, we tested if there were differences in naupliar predation as a function of crowding, food level and sex in Tigriopus brevicornis and T. fulvus. Results show that cannibalism was restricted to the first larval stages (N1 and N2). Both food availability and adult density significantly affected the predation rate. Contrary to earlier suggestions, adult males also preyed on the nauplii. We found no evidence that adults spare their own offspring, for neither T. fulvus nor T. brevicornis.This is in accordance with what one would expect for species having the life history characteristics of Tigriopus, i.e.: multiple broods and large number of offspring. Earlier results indicating parental care in Tigriopus must be taken with caution.