Clemson University's annual firefly count gets under way this weekend.

It's the fifth year for the Vanishing Firefly Project in which researchers enlist the help of the public in counting lightning bugs. It's thought there are fewer fireflies now than there were decades ago and the count is designed to track the number of the bugs.

In the past, the count was held one night each year. This year, the count begins on Saturday night but researchers hope volunteers will continue counting fireflies through the summer.

Volunteers count flashes or fireflies that appear in their field of vision during 60 seconds, then report to Clemson by entering the information on a computer, an iPhone app or, beginning this year, a new Android smartphone app.