I'm currently agonising over my Walking Stick Insect. While I was there I completed my Fishing Aspiration on one sim and am 3/4 of the way to the other. I've also filled my Base Game Fossil collection while there
Some insects only unlock at one at a time (like the fishing skill unlocks fish) and the Walking Stick Insect is the very last one. I don't know why it calls itself 'uncommon' when it's so particular about both time and place. I found the Dragon Dragonfly ages ago.