[This was written by Fran Siebrits and published online by Wild Magazine http://www.wildcard.co.za/, 2010]

According the latest study on fireflies, the blinking action performed by these winged beetles is for species recognition. Some groups of fireflies blink repeatedly in unison in a rhythmical synchronisation.

Fireflies, or lightening bugs, belong to the insect family called Lampyridae. There are roughly 2000 different species of fireflies, each with their unique blinking sequence. Without this physiological blinking pattern it would be extremely confusing and maybe even impossible for fireflies to recognise their own kind.
Fireflies use a chemical reaction known as bioluminescence to attract the opposite sex, therefore attributing to species survival. The light glows from a special organ in the lower abdomen which is different for each species. Even the larvae of fireflies emit light and are often referred to as ‘glow worms’.
Female fireflies recognise the synchronised blink of the males in their species. Just as we are able to pick out a friend in a crowd they are able to pick out their own species among a variety of other fireflies. Males blink their species-specific pattern, pausing momentarily in the hope of a response in the form of a single blink from a female firefly. The ladies are therefore able to pick out potential mates from their own species as the guys blink-on past trying to impress them.
Male fireflies, on the other hand, chose to synchronise their blinking patterns so that they have more chance of being recognised by the females of their species. They do not seem to be worried about competition within the species, as long as the female knows which males she can chose from.
Although the most commonly known fireflies come out at night when we can see their luminous glow, there are also many diurnal (or daytime) species. These fireflies have other ways of making sure that species recognition is maintained. Survival and reproduction are the most important factors in all species. Some just know how to make it a beautiful and romantic process.

Andrew Moiseff and Jonathan Copeland. Firefly Synchrony: A Behavioral Strategy to Minimize Visual Clutter. Science, July 2010: Vol. 329. no. 5988, p. 181