Sensory cues in host selection for oviposition by the cabbage butterfly, Pieris rapae

The butterfly Battus philenor forms search images for leaf shape when searching for its two larval host plants in southeast Texas. This behavior increases the rate of discovery of host plants and permits females to track changes in relative host plant suitability for larval growth. Apostatic selection resulting from search image formation is a likely explanation for divergence in leaf shape by the two host plants.