The ones glowing are the females in this kind of fireflies! Like this they attract the males, which are quite smaller and not that fancy.
The light pollution (they cannot attract mates so easily) and the pesticides are making the life of these creatures more difficult. Additionally when a field stops existing and a new building takes its place, this specific firefly for example cannot move that easily or even lay the eggs, where she used to, so they cease to exist.
The light is being produced through a chemical process and because of an enzyme.
You can aLao check out this sweet bee that visited us at Apollon, Naxos!
Bibliography
- https://academic.oup.com/bioscience/article/70/2/157/5715071?login=false (A Global Perspective on Firefly Extinction Threats)
- https://en.m.wikipedia.org/wiki/Firefly
Yannis and Stella @Apollon, Naxos 