Sri Lanka is a tropical island situated close to the southern tip of India. The invertebrate fauna is as large as it is common to other regions of the world. There are about 2 million and counting species of arthropods found in the world. Due to this, it is very difficult to summarize the exact number of species found within a certain region.
The following list is about some minor insect orders recorded in Sri Lanka.
Archaeognatha, are an insect order of the subclass Apterygota, which means they are insects without wings at any stage of the lifecycle. In the evolution of insects, Archaeognatha are the most primitive insects currently exists in the world. They have elongated bodies and arched backs. They have three long caudal filaments, where two lateral filaments are known as cerci, and the medial one is an epiproct. 350 species of Jumping bristletails belong to two families have been identified. Two species are known from Sri Lanka.[1]
Zygentoma is an insect order of the subclass Apterygota. The order includes silverfish, fishmoths, and the firebrats. All Zygentoma species have three long caudal filaments, where two lateral filaments are known as cerci, and the medial one is an epiproct or appendix dorsalis. There are five families in the order. 3 species are known from Sri Lanka.[2][3]
The order Embioptera, commonly known as webspinners, are a small group of mostly tropical and subtropicalinsects, classified under the subclassPterygota. The order has also been referred to as Embiodea or Embiidina.[4] The name Embioptera ("lively wings") comes from Greek, εμβιος, embios meaning "lively" and πτερον, pteron meaning "wing", a name that has not been considered to be particularly descriptive for this group of fliers,[5] perhaps instead referring to their remarkable speed of movement both forward and backward.[6]
Over 360 embiopteran species have been described,[5][7] along with estimates of around 2000 species being in existence today.[8] There is some debate as to the exact phylogenetic classification of Embioptera, with the order having been classed as a sister group to both orders Zoraptera,[5][9] and Phasmatodea,[10]
The following list provide the lacewings currently identified in Sri Lanka. Only four species found from this order within the country.[11][12][13][14][15]
Psocoptera are an order of insects that are commonly known as booklice, barklice or barkflies.[20] They first appeared in the Permian period, 295–248 million years ago. They are often regarded as the most primitive of the hemipteroids.[21] Their name originates from the Greek word ψῶχος, psokos meaning gnawed or rubbed and πτερά, ptera meaning wings.[22] There are more than 5,500 species in 41 families in three suborders. Many of these species have only been described in recent years.[23]
The Order Psocoptera is divided into three suborders. According to checklists by Smithers in 1967 and New in 1977, there are 67 accepted species of booklice found from Sri Lanka.[11] The checklist of New was advanced with the full description of two subfamilies Epipsocidae and Pseudocaeciliidae, from Sri Lanka.[12][24][25]
Thrips (order Thysanoptera) are minute, slender insects with fringed wings (thus the scientific name. Other common names for thrips include thunderflies, thunderbugs, storm flies, thunderblights, storm bugs, corn flies and corn lice. Thrips species feed on a large variety of plants and animals by puncturing them and sucking up the contents. A large number of thrips species are considered pests, because they feed on plants with commercial value. Some species of thrips feed on other insects or mites and are considered beneficial, while some feed on fungal spores or pollen. Approximately 6,000 species have been described. Thrips are generally tiny (1 mm long or less) and are not good flyers [citation needed], although they can be carried long distances by the wind. In the right conditions, like indoor grow rooms or greenhouses, many species can exponentially increase in population size and form large swarms because of a lack of natural predators, making them an irritation to humans.
The first comprehensive detailed work on Sri Lankan thrip fauna came through Schmutz in 1913. His checklist stood for more than 70 years with 43 new species.[11] In 1997, Oda et al. rediscovered and updated the thrip diversity, but with small collections from Sri Lanka.[12] The most recent work was done by Wijerathna, and he listed 16 species of thrips from 28 crops across the island. Currently, thrips documented within Sri Lanka included to 3 families - Aeolothripidae, Thripidae, and Phlaeothripidae, with 46 genera and 78 species.[26][27]
Fleas are insects that form the order Siphonaptera. They are wingless, with mouthparts adapted for piercing skin and sucking blood. Fleas are external parasites, living by hematophagy off the blood of mammals and birds. Over 2,000 species have been described worldwide.[28]
The following list provide the fleas found in Sri Lanka.[12] The first checklist of fleas in Sri Lanka was done by Iyengar in 1973.[11] 20 species are recognized, more taxonomic study is required.[29] The fleas studies were almost confined to parasitic sections, where W. W. A. Phillips documented 11 species of fleas in 1980.
The caddisflies are an order, Trichoptera, of insects with approximately 7,000 described species.[30] Also called sedge-flies or rail-flies, they are small moth-like insects having two pairs of hairy membranous wings. They are closely related to Lepidoptera (moths and butterflies) which have scales on their wings, and the two orders together form the superorder Amphiesmenoptera. Caddisflies have aquatic larvae and are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps, and temporary waters (vernal pools).[31] The larvae of many species use silk to make protective cases of gravel, sand, twigs or other debris.
The caddisfly diversity in Sri Lanka is fairly studied from British times to present day. However, the first comprehensive work was done by Schmid in 1958.[32] Then in 1973, Malicky updated the checklist.[12] Currently 188 number of caddisfly species belongs to 18 families are identified from Sri Lanka.[11][33][34][35][36]
Order Strepsiptera, commonly called, twisted-wing parasites, are an endopterygote order of insects. The order consists with nine extant families with about 600 species. Adults in most of their lives are spent as endoparasites in other insects, such as bees, wasps, leafhoppers, silverfish, and cockroaches.[37] Males have well-developed pair of hind-wings and reduced fore-wings. Females wingless and usually do not leave their hosts.[11]
The first scientific observation and detailed work on strepsipterans of Sri Lanka was done by Kathirithamby in 1994.[38][39] In 1997, Kifune discovered 20 strepsipterans from Sri Lanka, with 7 new species. All these new species genera are endemic to the country.[40][12][41][42]
Phthiraptera, is an insect order, which comprise more than 5,000 species of wingless insects. All lice are obligate parasites which live externally on warm-blooded mammals and birds. The three cosmopolitan species of lice live within the humans, on head, body and pubic region. They are divided into two groups, sucking lice and chewing lice. The exact number of lice in Sri Lanka is not known. Only some species have been documented.[43]
Mecoptera is an insect order with about 600 described species. They are commonly known as scorpionflies, due to enlarged genitals possessed by males, which resemble the stinger of a scorpion. They are one of major pollinators gymnosperms along with bees. Detailed work on mecopterans in Sri Lanka not yet carried out. Two species are known to live in Sri Lanka.
Plecoptera is an insect order with about 3,500 described species with worldwide distribution. They are one of the most primitive winged insects. The body is very simple, chewing mandibles, large compound eyes with two or three ocelli. Detailed work on plecopterans in Sri Lanka not yet carried out. Eight species within two families are known to live in Sri Lanka.
^Donald J. Borror; Charles A. Triplehorn; Norman F. Johnson (1989). An Introduction to the Study of Insects (6th ed.). Harcourt Brace College Publishers. p. 247.
^E. S. Ross (2000). "Contributions to the biosystematics of the insect order Embiidina. Part 1. Origin, relationships and integumental anatomy of the insect order Embiidina". Occasional Papers of the California Academy of Sciences. 149: 1–53.
^ abcdefWijesekara, Anura; Wijesinghe, D.P. "History of Insect Collection and a Review of Insect Diversity in Sri Lanka". Ceylon Journal of Science: 59. CiteSeerX10.1.1.379.2411. ((cite journal)): Cite journal requires |journal= (help)
^New, T. R. (1977). "Epipsocidae and Pseudocaeciliidae (Psocoptera) from Sri Lanka". Oriental Insects. 11 (3): 409–420. doi:10.1080/00305316.1977.10433824.
^Chantaramongkol, P. (1987). "The Caddisflies of Sri Lanka". Proceedings of the Fifth International Symposium on Trichoptera. Proceedings of the Fifth International Symposium on Trichoptera Volume 39 of the series Series Entomologica. pp. 109–110. doi:10.1007/978-94-009-4043-7_19. ISBN978-94-010-8294-5.
^Malicky, Hans (1983). "Caddisflies (Trichoptera) from Parakrama Samudra, an ancient man-made lake in Sri Lanka". Limnology of Parakrama Samudra — Sri Lanka. Limnology of Parakrama Samudra — Sri Lanka. Volume 12 of the series Developments in Hydrobiology. pp. 227–228. doi:10.1007/978-94-009-7281-0_21. ISBN978-94-009-7283-4.
^Whiting, M. F (2003). "Strepsiptera". In Resh, V. H. & R. T. Cardé (ed.). Encyclopedia of Insects. Academic Press. pp. 1094–1096.
