The fauna of Bangladesh includes about 1,600 species of vertebrate fauna and about 1,000 species of invertebrate fauna based on incomplete records. The vertebrate fauna consists of roughly 22 species of amphibians, 708 species of fish, 126 -species of reptiles, 628 species of birds and 113 species of mammals.[1] The invertebrate fauna includes about 30 species of aphids, 20 species of bees, 178 species of beetles, 135 species of flies, 400 species of spiders, 150 species of lepidopterans 52 species of decapods, 30 species of copepods, 2 species of starfish and some species of sand dollars, sea cucumbers and sea urchins. Bangladesh's wide variety of ecological conditions, encompassing the long sea coast, numerous rivers and their tributaries, lakes, haors, baors, ponds and other forms of wetlands, lowland evergreen forests of tropical nature, semi-evergreen forest, hill forests, moist deciduous forests, swamps, and flat lands with tall grasses, has ensured the vast diversity of species found in the country.[2][3] However, the increasing population, unplanned urbanization and expansion of agriculture and industry have been significantly affecting the ecological structure of Bangladesh, leaving several species extinct and many others endangered.[4]
The invertebrate fauna so far recorded in Bangladesh comprises about 1,000 species. 18 species of bees have been discovered. Most of them are solitary bees consisting of 11 species. The rest include 4 of honeybees, 2 of bumblebees and the only stingless bee species, Trigona fuscobaltiata.[5]
There are a total of 35 species of scarab dung beetles found under 8 genera. The most common genus is Onthophagus. Another 30 species of leaf-eating scarabeids are also found. The ladybirds includes about 93 species, 80 of which are beneficial. 20 species of fireflies have also been discovered in the country.[5]
The most common indoor flies include housefly, the lesser housefly, the stable fly, the blue bottle fly, the green bottle flies and the flesh flies. The common outdoor flies include the black flies, the deer flies, the horse flies, the hover flies, the crane flies and some muscoids.[6] There are also some 113 species of mosquitos discovered in Bangladesh, the most common genera are Anopheles, Culex, Aedes, Mansonia, Psorophora and Haemagogus.[7]
More than 400 species of spiders are found under 134 genera, and 22 families. The largest family is Araneidae, consisting of some 90 species.[7]
About 124 species of butterflies have been discovered. Most of the species dwell in the northeast and southeast regions of the country.[8] There are also some species of moths, most commonly the snout moths, Scirpophaga incertulas, Chilo polychrysus, Cnaphalocrocis medinalis, Achyra nudalis, Scirpophaga nivella, Leucinodes orbonalis, Corcyra cephalonica, Plodia interpunctella and soforth.[9]