Generally, male butterflies of butterfly species emerge earlier than female butterflies. After that, the male butterfly flies around, looking for the newly fledged female butterfly based on the sex pheromones emitted by the female butterfly, and quickly chases and mates. Before mating, there is more or less a courtship process. The pattern and color of the female butterfly and its pheromones all play an important role. Finally, the structure of the external genitalia must match.
If a female butterfly perched on a leaf has already mated, when the male butterfly flies, she will spread her wings flat and raise her abdomen high, and never take off. This is a sign that the female butterfly does not accept mating. Therefore, the male butterfly flies around for a while and has no choice but to let him go; otherwise, mating will begin. Sometimes a female butterfly that does not need to mate may encounter several male butterflies chasing each other while flying in the air. They press closely and fly in circles, becoming inseparable and rising to high altitude together. At this time, the female butterfly suddenly grabs her wings and flies away. Down and down rapidly, this kind of flight makes the male butterfly seem to be lost and does not know where the female butterfly is, so the female butterfly can escape.
This "escape from marriage" instinct of female butterflies is quite interesting. There are also some butterflies, such as most species of the family Sericidae. After mating, the female butterfly grows various post-mating derivatives at the base of the opening of the mating sac, which acts as an obstacle to prevent re-mating. Each insect has its own type, which is a major feature in identifying species.