Flashing Lights=Beautiful Nights

Fireflies are mostly nocturnal, coming out in early evening, right before the sun goes down, to court and attract a mate. Outnumbering females 50 to one, fireflies seen twinkling at dusk and into the nighttime sky are always male. Keep in mind that there are more than 170 different species of fireflies in the United States, and more than 2,000 species around the world, and each different species is recognized by the duration and frequency of flashes. Scientists from the Department of Entomology at Purdue University explain that of the 43 known species of fireflies found in Indiana, only 30 flash. Some species flash primarily at dusk and stop when it gets dark, whereas others do not start flashing until after dark, and carry on well into the night. Arwin Provonsha, curator of the Purdue Entomological Research Collection, explains that fireflies that flash in Indiana can be classified as follows: Photinus have a yellow flash, Photuris have a green flash and Pyractomena have an amber flash.

When the male firefly flashes, he is inviting the female to mate with him. The flashing serves as a secret code that a female of the same species can understand. Female fireflies generally remain close to the ground, preferring to perch on blades of grass or weeds, waiting to decode the flashing lights from the males above. Females decode the flashes by determining the color, brightness, length of the flash and the time between flashes. That is how she decides whether or not the male above is a suitable mate. After the flash pattern has been decoded and the mate determined to be suitable, she activates her light organ, which serves as a spotlight in the dark of night that allows the male to find her perched below. The remaining 13 species of the 43 in Indiana fly during the day and find mates with chemical attractants rather than with flashing lights. In some species of fireflies, the females do not have wings, and rely on their flashes to attract males.