On my fennel bush I have had over 100 caterpillars, some moved on but the last crop has been outstanding. One day I saw one as it was “hatching”.. . that morning early, the tiniest black and blue one coming out and a little later these two! I looked it up last year and butterflies mate as soon after coming out as possible. They mate for over an hour! Last time I got pictures… this time I got it on video! Pretty Neat!