Experiments on the Selection against Colour Oddity of Water Fleas by Three-Spined Sticklebacks

To determine whether odd individuals were more vulnerable to predation than the majority of a swarm, four types of choice experiments were conducted with three-spined sticklebacks (Gasterosteus aculeatus L.) as predators and water fleas (Daphnia magna) as prey, attempting to separate out the roles of oddity and conspicuousness. Odd-coloured water fleas were attacked more often by the predators than the majority, suggesting that oddity is effective apart from conspicuousness, which, however, also played a role.