Firefly (jonaki poka) small, luminescent, carnivorous beetle of the family Lampyridae, order Coleoptera. From antiquity these insects have attracted the attention of naturalists, biologists, amateurs, children, and the common man. Fireflies are also known as glow-worms or lightning bugs. In many species the females are wingless. The family comprises of about 2000 species belonging to 100 genera and seven subfamilies. These nocturnal insects can be very small (less than 5 mm), or as large as 22 mm or more. Luciola (from Old World) is the largest genus with about 290 species. Asia has about 280 species including 21 from Sri Lanka, and 17 from Japan. In Bangladesh four species of fireflies have so far been recorded (Lamprophorus tenebrosus, Lampyris marginella, Luciola chinensis, and L. ovalis).
Essentially, they are all nocturnal. Adult females of many species are larviform, while others are normal with shorter wings. Adults of many species do not feed. The giant glowworm of Bangladesh Lamprophorus tenebrosus shows sexual dimorphism like many other fireflies. Its larviform female measures over 60 mm, while brownish male is about 25 mm. Its larvae are predatory on the giant snail, Achatina fulica, a serious pest of vegetables and other crops. In fact snails, slugs and other mollucs form the principal food item of larval fireflies, though other soft-bodied animals such as earthworm and insects are included in their diet.
Males, females, and larvae emit a heatless, greenish yellow to reddish orange light; in some species even the eggs glow. The light is believed to stimulate sexual attraction between adults and is produced by organs located on the underside of the abdomen. The intensity and frequency of flashes vary from species to species and probably serve to attract males and females to each other. Fireflies are well represented in temperate regions, although the majority of the species are tropical and subtropical. [Md Sohrab Ali]