bottle w/ glowstick Lightning Bug (or FireFly as some say;) Once made, they can be saved each year and then a new glow stick can be added inside. The kids love flying these around the yard at night! Could be a fun camping craft.
Fireflies mainly emit light to attract mates, though this communication method is also used to defend territory. Though it is mostly adult fireflies that glow, there are some species where the larvae and the eggs also emit light.