Trail Effect of light in photography

I was on a visit to nearby village. It was month of November, i was standing in the balcony and noticed that flies and insects are roaming around the street night lamp. I actually started to capture the light only. but after one shot i found that i can capture trailing effect of light reflected from insects. Then i set exposure time to 1 sec. and I got this result, This is first time i got trailing effect of light.
Camera : Canon EOS 550D, f-stop - f/5.6, exposure time : 1 sec., ISO : 800, exposure bias : -1 step, focal length - 55 mm, No flash