The feeding strategies of two large marine copepods

We compared the feeding behaviour of the two copepods Paraeuchaeta norvegica and Chiridius armatus, allowing them to prey on other calanoids in small-scale laboratory experiments. Several differences were found. When fed either live, free-swimming or dead, non-moving prey, P.norvegica seemed unable to locate the dead prey items while C.armatus foraged heavily on them. When starved, P.norvegica increased its feeding rate while C.armatus reduced its feeding after an initial increase. None of the predators changed their feeding rates when exposed to light. Nighttime versus daytime feeding was tested only with P.norvegcia, which seemed to possess an endogenous feeding rhythm with increased rates at night. Chiridius armatus infected with epizooic ciliates appeared to have increased feeding rates.