STUDIES ON THE HOST PREFERENCE OF CABBAGE BUTTERFLIES(PIERIS RAPAE L.)III : MECHANISM OF FOOD PREFERENCE OF CABBAGE BUTTERFLY LARVAE I

Abstract

The larvae developed in the cabbge field decidedly prefer cabbage leaves to radish leaves, and the larvae grown in the radish field tend to prefer radish leaves. The preference behavior in the former is more conspicuous than in the latter^<3)>. This paper deals with the results of the preference test of the cabbage butterfly larvae for cabbage and radish leaves coated with cabbage or radish juices, especially of the analysis of the mechanism of food preference. The results are summarized as follows : 1) The larvae developed in the cabbage field decidedly prefer cabbage leaves to radish leaves when both leaves are coated with radish juice, but they show no precise tendency in preference when the leaves are coated with cabbage juice. 2)The larvae grown in the radish field prefer cabbage leaves to radish leaves when both leaves are coated with radish juice, but when the leaves are coated with cabbage juice the preference is not so distinct. 3)According to the results of the above experiments, it seems that the chemical attractants of the cabbage and radish leaves are the most important factor for the food preference of cabbage butterfly lervae. It was ascertained that the difference in the food plants of the larvae caused the difference in the character of preferring food plants.