This maybe released August 21 and we already have here what would be the complete list of tasks that the quest will be asking. Since this post was written before the day of release, there still a chance it maybe change but rest assured that together with our community and your help we will update it immediately.
Firefly Fancy Quests 1: Farmville 2 Looking for Lightning Bugs
Water 25 Spaghetti Squash to attract some fireflies.
Feed 3 Adult Chicken. They can help us look!
Perform 10 helpful actions on Neighbor farms to check for fireflies.