Why fireflies are only spotted in summer and where lightning bugs live the rest of the year

Firefly fans who'd like to see lightning bugs year-round are out of luck. 

The insect, which is a type of beetle, is usually seen only between spring and summer, with different species emerging at different times. The first fireflies of the season come out later in the year as you move farther north. 

The fireflies people see glowing and flying around are adults, said Sara Lewis, author of "Silent Sparks: The Wondrous World of Fireflies." Their time aboveground before dying is brief, with fireflies actually spending the bulk of their lives living underground.