I going on a camping trip almost every year with to the mountains of North Carolina along the New River. We usually do this trip in the fall but this year we went in June. Fire flies were not on my mind but they were a very welcomed surprise. Once it got dark, 1000s of them lit up the night.
I took this shot just right on our camping site. I put my camera in interval mode and let it go. F/2.8, iso 1600 and 30 second exposures I believe. The fireflies never got super close to my camera and/or I guess I was shooting to wide to get the bigger yellow dots that some firefly photos have. But if you view this on a large monitor you can really see how many there are. I used just over 300 images to add in the star trails and all of the fireflies, using the lighten blend mode in photoshop.