I didn't see this mentioned in the Seasons strategy guide, so I'm not sure if it's known. I was playing one of my families with a toddler, when suddenly the toddler started crawling to the backyard. There was a butterfly icon in the queue. It seems toddlers can "chase butterflies" autonomously or by clicking the ground below them. It was so adorable. When the fireflies appear, I will attempt to do the same with them.
Love, Charmy