File:Garden Doodles (34506755154).jpg

High season of fireflies. This image combines several exposures (each about 20 seconds) in order to collect enough traces of fireflies wandering through the garden on their wedding flight. (Easily done in Photoshop by combining layers with blending mode "Lighten").

Fireflies are only active in the late dusk, before it becomes too dark. Because of the remaining daylight it is not possible to do it all in a single long-term exposure, because this would make the environment appear too bright.

Here is some information from Wikipedia about fireflies:

The Lampyridae are a family of insects in the beetle order Coleoptera. They are winged beetles, commonly called fireflies or lightning bugs for their conspicuous use of bioluminescence during twilight to attract mates or prey. Fireflies produce a "cold light", with no infrared or ultraviolet frequencies. This chemically produced light from the lower abdomen may be yellow, green, or pale red, with wavelengths from 510 to 670 nanometers.

Light production in fireflies is due to a type of chemical reaction called bioluminescence. This process occurs in specialized light-emitting organs, usually on a firefly's lower abdomen. The enzyme luciferase acts on the luciferin, in the presence of magnesium ions, ATP, and oxygen to produce light.