Long-Distance Movement of Pieris rapae

(1) Adult female butterflies were bred on artificial diet containing dye so that they laid coloured eggs, and the distribution of eggs was used as an amplifier for the distribution of adults. (2) The butterflies were released in a 1 km square grid of cabbage plants. The observed pattern of coloured eggs agrees with independent predictions based on Jones's (1977) rules for short-distance movement. (3) Each butterfly flies about 700 m per day over the ground, and ends the day 250600 m from where she started. (4) Each butterfly maintains a preferred direction throughout one day, but the direction changes unpredictably from day to day. (5) The butterflies in these experiments laid only 10%? of their daily complement of eggs, because they could not find enough host plants. (6) This method of studying animal movement overcomes several flaws inherent in previous methods, but is restricted to distances of a few km at most.