Courtship behavior of the male sulfur butterfly Colias erate toward experienced females that were inhibited from showing mate refusal behavior by experimental manipulation.

Abstract

For high school students, evolution of animal behavior seems to be the most difficult concept to understand due to unavailable examples off ered by text books. In the present study, we developed teaching materials for the evolution of animal behavior and proposed the methodology.　In the Japanese sulfur butterfl y Colias erate, polyandrous alba females are the dominant morph in the female population, though mated females do not easily re-accept males courting.　The wings of mated alba captured in the field were closed by glue, and they were tethered in the grassland where males were searching for mates.　We observed 1,830 entries of males into the imaginary hemisphere of 1 m radius around each female.　A half of the males noticed and visited our females.　Due to the closed wings, every female was unable to show the mate refusal posture, so the males continued their courtship behavior.　However, the duration of hovering around the females was short in the morning, and most males left the females without touching them.　Because newly emerged females promptly accept copulation with males in the early morning, males might prefer virgin females to mated ones.　On the other hand, males that visited the females around noon prolonged the duration of hovering and tried to copulate persistently.　The adaptive significance on the behavioral sequence was easily observed due to the closing femalesʼ wings.　Manipulation of the butterfl y wings in the field observation was discussed in the viewpoint of the teaching materials for high school education on evolutionary biology.