Lightwings
A white, glowing insect somewhere between a butterfly and a moth, as they share characteristics and feeding habits akin to both insects (but they have a particularly strong attraction to decaying matter), and though they seem to prefer evening and early morning hours, they can appear at any time of day. Their bioluminescence also seems to be toxic if eaten, making them a target to only a few predators that can stomach them, so perhaps their glow is a warning.
They are seen as special and even holy to some, often tied to the spirits of ancestors and lost loved ones, perhaps because they seem unusually fearless around humans, especially ones who use magic.
There are stories that say if you kill a lightwing, especially on purpose, you are cursed to a life of hardship, so leave the pretties be!
Chrysalis and caterpillar stages:
Just like butterflies and moths, lightwings go through egg, caterpillar and chrysalis life stages before emerging into their final winged selves. Their caterpillar forms are also bioluminescent, but to a MUCH less striking degree than their adult form, so they can go more unnoticed in nature.