I've not seen fireflies flashing in synchrony, but I have seen firefly 'swarms' in Taiwan (2-3 times on calm and foggy July evenings at elevations about 1500 m in a forested area of Yushan National Park) It seems that they will nest together in the leaf litter for the day, so when it is time to emerge for the night, they'll all emerge together. The first time I saw it (July 1999) was the most spectacular. Hundreds emerged from litter beside the trail and we were able to stand in the middle of the swarm (<5 meters wide), totally dazzled by the blinking lights. Part of the impressiveness was how silent it all was.
Hiking past this area in late evening, I've seen the swarms a few more times, but 10-30 meters off the trail. Aborigine friends of mine have recently purchased land near the park. On this land, displays of fireflies are frequent in late spring and summer--just not in the same densities. They have noticed a negative correlation between pesticide use and fireflies and hope to keep their land fairly pesticide-free. Unfortunately, they will have no control over the management of uphill lands as they are cleared for farming. In Taiwan, as elsewhere, humans are clearing land for farming to the edges of the national parks. In southern Taiwan, we have cockroach-sized fireflies (2-3 cm long). Their lights will stay on for a minute, maybe more. I found that 5-7 in a plastic bag were more than adequate to light my path. CL ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Cara Lin Bridgman P.O. Box 013 Phone: 886-4-2632-5484 Longjing Sinjhuang Taichung County 434 Taiwan http://megaview.com.tw/~caralin/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
