I've never imagined that a bug can make me cry

Nah I'm not a noob and I know it's just spawn but I've had a nest with 3 bugs, I've kept it in a well-ventilated space, it was healthy, I've fed it the food it likes (peeled almond and pumpkin seeds) and they've been thriving, I've seen them even after the 72 hours end, and they've been perfectly fine, I've thought that I would be able to keep them till they're adults. But sadly I've woken up today and all of them were dead, I've thought about that it's not the end and they'll spawn again, but it just hurt me a lot and it's been breaking my heart. Why did they die I thought everything was fine, oh well.