User:Kgvyas09

'''Study of Psocoptera, Mallophaga, Siphunculata, Hemiptera and Thysanoptera Orders. 

1.	ORDER – PSOCOPTERA- PSOCIDS OR BOOKLICE

(Psoco-ptera, from generic name Psocus and Greek pteron = wing)

	Small, soft-bodied insects with two pairs of membranous wings or wingless. 	 When at rest, most winged species hold their wings steeply roof-wise over the body. 	 Head quite broad, with long filamentous antennae and biting mouthparts. 	 Eyes often large and protruding from the sides of the head. 	Legs with two or three tarsal segments. 	 Cerci absent. Metamorphosis simple, usually with six nymphal stages before reaching maturity, although some wingless forms may have fewer stages. 	The best known Psocids are the very small, wingless species commonly known as Booklice or Dustlice, which often infest houses, libraries, food stores, warehouses and other buildings. 	However, the majority of species, often called Barklice, live outside on tree bark, leaves, fences, stone walls and in old birds' nests. Most of these outdoor species are fully winged. Example :- 	Booklice - - Liposcelis spp. Psocids - Cerastipsocus venosus. Booklouse (or Dust Louse) - Liposcelis spp. Description:- 	Small wingless species, up to 2 mm long. 	Pale yellowish-white or brown in colour. 	 'Thigh' segments (femora) of hind legs very broad. 	Chewing mouthparts 	Tarsi 4-segmented 	They are generally gray or brown in color 	Cerci absent “cerci are either of a pair of simple or segmented appendages at the posterior end of various arthropods that usually act as sensory organs” 	Indoor species are usually wingless (or wings are reduced to small scales) and called booklice.

Biology:- 	Mainly found indoors (at least in temperate regions), living on all kinds of starchy organic matter such as stored food and paper. 	Often found among undisturbed books and under peeling wallpaper, feeding on glue, paste and minute traces of mould. 	Flour, meal and other cereal products are also eaten. 	Breed continuously throughout the year indoors.

Distribution: - 	Cosmopolitan, in warehouses and other buildings. 	Often transported in the cargo holds of ships. 	Abundant worldwide, but often overlooked because of their secretive habits.

Example:- Barklouse - Psocus spp.

Description:- 	Small (1/32-1/4 inches long) 	Soft-bodied insects 	With long, thread like antennae of 12 to 50 segments 	Chewing mouthparts 	Tarsi 4-segmented 	They are generally gray or brown in color 	Cerci absent “cerci are either of a pair of simple or segmented appendages at the posterior end of various arthropods that usually act as sensory organs”. 	Outdoor species typically have two pairs of wings (males only) held roof-like over the body and called barklice. Biology:- 	Found outdoors on various trees and bushes, mainly feeding on algae and minute fungi growing on bark and leaves. 	Often several generations in a year. 	Psocids undergo simple metamorphosis 	The females of some species of psocids can reproduce without fertilization 	Each female deposits singly or small batches of sticky, oval, and covered with a silken web or debris eggs on food sources. 	Females lay in average from 20-50 eggs/lifetime. Eggs deposit average depends on the time of the year. 	At 50-87 °F (Oct.- Jan.), eggs deposit average 20 	At 60-90 °F (June- Aug.), eggs deposit average more than 50. 	Eggs hatch in one-three weeks. 	Depending on optimal conditions (temperature, humidity and food availability), nymph will go through 3-8 molts in about two –eight weeks. 	Adults will live normally from one to six months.

Distribution:- 	Most booklice species are found in natural habitats such as animal nests, tree trunk crevices, under bark (hence the alternative name of barklice) and on leaves. 	 However, those species that have achieved pest status are widely distributed and often found in warehouses, food manufacturing premises, granaries and museums as well as domestic and retail premises. 	Here they will infest materials of plant and animal origin including stored food, plaster, leather, woodwork and even books. 	Many species are cosmopolitan and their countries of origin are unknown. 	They are widely distributed in the U.K. where their activity, reflecting seasonal influences, is greatest between April and November. 	Different species exhibit different temperature requirements. 	Thus Lepinotus patruelis is frequently encountered in cool situations, e.g. warehouses, whilst Liposcelis bostrychopilus, which is thought to have originated from Africa, prefers warmer situations, e.g. houses and retail premises. 	In heated buildings coninuously brooded species (e.g. Liposcelis spp.) will continue to breed throughout the year. Other species (e.g. Trogium spp.) produce only one generation per year and will overwinter as nymphs.

2.	ORDER-MALLOPHAGA - BITING LICE (Mallo-phaga, from Greek mallos = hair, phagein = eat)

	Small, wingless insects living as external parasites of birds or, less frequently, of mammals. 	Head fairly broad, with very small eyes and short antennae which are often concealed. 	Mouthparts of a modified biting type. 	Body usually flattened, with the prothorax distinct from the other two thoracic segments, which may be partly fused together. 	Cerci absent. 	The legs have one or two tarsal segments, the last of these bearng one or two claws with which the insect clings tightly to the feathers or fur of its host. 	 There are three nymphal stages, with no obvious metamorphosis. 	Biting Lice feed mainly on particles of skin, feathers and fur. 	 Some species take blood, sometimes puncturing the skin with their own jaws, but more often feeding at small wounds made when the host birds or animals scratch themselves. 	 Most lice are confined to one host or a group of closely related host species. 	 Some are of great economic importance when they infest domestic poultry or other livestock, but none are directly associate with humans.

Ex. :- Bird Louse - Nirmus punctata Description:- 	More or less whitish in colour, with darker brown markings on the head, thorax and abdomen. 	Head broad, with mandibulate mouthparts. 	The range in size from 0.5 to 10 mm long dorsoventrally flattened. 	Antennae short; 3-5 segmented. 	Eyes reduced or absent. 	Tarsi 1- or 2-segmented, most species have two small claws.

Biology:-

	Most feed on fragments of hair and feathers though some such as feed on their hosts blood as well 	Some have formed a symbiotic relationship with bacteria which live in special Mycetocytes in the insects fat reserves, these may help with the digestion of blood 	They are often adapted to live on particular parts of their hosts bodies. 	They can only survive for a maximum of three days after their host has died and may hitch a ride on a passing fly (phoresis) in the hope of reaching a new host, they may also use phoresis in order to spread to a new host even if the present one is still alive. 	Females lay up to 100 eggs which are cemented to the hair or feathers of the host with a clear fast drying glue which is secreted onto the hair or feather by the female immediately before she lays the egg. The eggs take about 3 or 4 days to hatch and the nymphs go through 3 larval instars in about 20 days before they reach maturity.

Distribution:- There are about 2,800 species dispersed worldwide.

3.	ORDER-SIPHUNCULATA (ANOPLURA) - SUCKING LICE (Siphunculata, from Latin siphunculus = little tube)

	Small, wingless insects living as external parasites of mammals. 	Head usully narrow and the eyes are reduced or absent. 	Antennae short 	. Mouthparts highly modified for piercing and blood-sucking, and retracted into the head when not in use. 	Body usually flattened, with all the thoracic segments fused together. 	 Cerci absent. The legs have one tarsal segment ending in a strong claw. 	 The claw is hinged in such a way that it can be closed tight against the tarsus to grip the hair of its host. 	There are three nymphal stages, with no obvious metamorphosis Sucking Lice feed exclusively on blood, obtained by piercing the skin of their host. 	As with the Biting Lice, most are confined to one host or a group of closely related host species. 	The best known family is the Pediculidae, on account of its human-infesting species. 	The most important of the other Sucking Lice are those of the family Haematopinidae, which affect domestic livestock such as pigs, sheep and cattle.

Examples: - 	Human Louse (Hair & Body Louse) Human Crab Louse

•		Anoplura/Siphunculata (sucking lice) 	Small, wingless parasites of mammals. 	Head narrow and eyes reduced. 	Antennae short. 	Piercing/sucking mouthparts, retracted into head when not feeding. 	Feeds solely on blood. 	Each leg ends in a strong claw. 	Eggs are usually stuck on to the host's hair. 	500 species worldwide, fewer than 50 in Europe. Human Louse - Pediculus humanus Description:- 	The Human Louse exists as two distinct races - the Head Louse (P. humanus capitis) and the Body Louse (P. humanus corporis). 	The Head Louse is more or less whitish in colour and up to 3 mm long; the Body Louse is generally darker and larger, up to 5 mm long. Biology:- 	Found on the hairy parts of the human body. 	Fortunately, the Head Louse does not appear to carry any diseases. 	Eggs are laid within 14-18 hours after mating. 	Eggs are firmly attached to hair close to the scalp by "cement" or glue consisting of peptides and lipids that are very close in composition to some components in human hair. 	 Egg casings found on hair are often called nits; 	Egg stage takes from 7 to 12 days. 	 Nymph molts 3 times before becoming mature egg-laying adult, this stage takes from 8.5 to 11 days. 	Mature adult young mature female louse lays up to 9 eggs daily for period of 8-9 days after single insemination, with time her fecundity decreases. 	 Adults live for up to 32 days taking blood meals every 4-6 hours. 	Development is fairly rapid and can be as short as 15-20 days from the egg to adult stage. Distribution:- 	The human louse occurs on man in many parts of the world and is almost exclusively a parasite of man. 	It is found most of the countries.

Ex. :- Human Crab Louse - Pthirus pubis

Description:- 	Short, broad body with rather stout claws on the middle and hind legs. 	 Greyish-white to reddish in colour. 	Up to 2 mm long.

Biology:- 	Lives on the hairy parts of the human body, but confined to the pubic areas and other lower parts. 	Pubic lice lay less than 30 eggs per female. The eggs hatch after seven to eight days, 	The life-cycle from egg to adult is 22-27 days. 	 From the egg hatches the 1. nymphal stage, which after three moultings develop to nymph 2, nymph 3 and to either male or female louse. 	 The incubation period of the egg is 7-8 days, while the rest of the cycle is taken up with the development of nymphal stages. 	 The average adult life is 17 days for females and 22 days for males.

Distribution:- 	The crab louse occurs on man in many parts of the world and is almost exclusively a parasite of man. 	Ferris (1951) noted that it had been recorded from a chimpanzee from the French Congo.

4.	ORDER-HEMIPTERA - TRUE BUGS (Hemi-ptera, from Greek hemi = half, pteron = wing) Examples:-	 Homoptera & Heteroptera

	Small to large sized insects of widely differing shapes and habits, but all with piercing mouthparts adapted for sucking the juices of plants or animals. 	The mouthparts form a relatively stout rostrum (often called the 'beak') which is normally held horizontally under the body when not in use. 	Antennae often quite long, but generally with few segments and nearly always less than ten. 	Two pairs of wings are normally present, but wingless forms are fairly frequent. 	The order is split into two distinct suborders - the HOMOPTERA and the HETEROPTERA based largely on differences in wing structure. 	Thus, when wings are present, the front pair may be uniformly membranous or stiffened throughout (suborder Homoptera, from the Greek homos = uniform), or the front pair may be clearly divided into two regions - a hardened, leathery basal area and a membranous tip (suborder Heteroptera, from the Greek heteros = different). The hindwings are always membranous.

ORDER HEMIPTERA IS DEVIDED IN TO TWO SUBORDERS. Order Hemiptera – 1. Suborder Homoptera. 2. Suborder Heteroptera Examples:- 	Aphid or Greenfly 	Whitefly 	Mealybug 	Scale Insect 	Froghopper or Spittlebug 	Leafhopper 	Treehopper 	Cicada 	Lantern Fly

CEREAL GRAIN APHID - Sitobion avenae Description:-

	Up to 3 mm long. 	 Body colour rather variable, from yellowish through green to dark brown. 	Legs and antennae usually more or less black. 	Cornicles always black. 	Like most aphids, it has winged and wingless forms.

Biology:-

	Found on cereals and grasses, usually feeding on the underside of leaves and on the flower heads. 	May cause considerable crop losses when feeding on the ripening ears of wheat, oats and other cereals. 	It is also a vector of some cereal and grass virus diseases. 	Reproduction is generally asexual, with several generations during the year. 	The asexual females give birth to live young. 	Winged asexual forms are produced at certain times of year, particularly in summer and autumn, and these fly off to colonise new plants. 	Sexual forms (males and females) are sometimes produced in autumn and after mating the sexual females lay overwintering eggs, which hatch in the following spring. 	This is a fairly typical aphid, similar to many of the species commonly found on vegetable crops and ornamental plants, and known as greenfly, blackfly or plant lice. 	The life cycle of some species is even more complex than that of the Grain Aphid, involving alternation and migration between different summer and winter host plants. 	For example, the Black Bean Aphid (Aphis fabae) lives on beans, spinach, docks and other herbaceous plants during the summer, but migrates to spindle (Euonymous sp.) and a few other trees in autumn, to spend the winter. 	There is a return migration to the summer host plants in spring. Distribution:-

	The Grain Aphid occurs throughout Europe and the British Isles. 	Also found in North America and Japan.

Ex.:- Glasshouse Whitefly - Trialeurodes vaporarium.

Description:-

	Small insects, 1-2 mm long, with the body and wings dusted with a white powdery wax. Biology:- 	A damaging pest found on the undersides of leaves and infesting many glasshouse and indoor plants, especially tomatoes and cucumbers. 	Sometimes occurs on outdoor plants and weeds in summer. 	Breeding continues throughout the year in heated glasshouses and is mainly asexual. 	Adults may live for a month or more and each female lays up to 200 eggs on the undersides of leaves. 	The young nymphs crawl about on plants for a few hours after hatching, but then settle to feed. 	Their legs and antennae degenerate and they become immobile scales which feed for about 2 weeks before entering a non-feeding stage from which the adults emerge. 	 Development from egg to adult takes about 3-4 weeks in warm conditions. 	Biological control is widely used in commercial glasshouses, by introduction of a small parasitic wasp, Encarsia formosa, which attacks and kills the whitefly scales. 	Other biological controls becoming available to gardeners include a small black ladybird, Delphastus sp., a small predatory bug, Macrolophus sp

Distribution:-

	Native of Central America, but has been imported and spread by trading and now occurs in North America, Europe, Britain and other temperate regions, where it can survive harsh winters in heated glasshouses.

Ex.:- Coffee Mealybug - Pseudococcus adonidum

Description:-

	Wingless females and young stages (illustrated) are up to 6 mm long and covered with a white or yellowish wax secretion. 	The males are 1-2 mm long, lemon-yellow in colour, with a single pair of white wings.

Biology:-

	This and several other similar species are common pests of glasshouse and conservatory plants. 	 They live on leaves, stems, buds, flowers and fruits. 	Persistent infestations weaken the plant and cause fouling of the plant surfaces with sticky honeydew on which sooty moulds tend to grow. 	Females lay batches of 100-150 eggs protected by a covering of woolly wax. 	In warm conditions, eggs may hatch in a few days and the young mealybugs then crawl over the plant for a few hours before settling to feed. 	They often remain immobile for long periods whilst feeding, but can move to new feeding sites when necessary. 	Development from egg to adult may be as short as three weeks. 	The winged males emerge from delicate white cocoons, but are short-lived, surviving just a few days for the purpose of mating.

Distribution:-

	Cosmopolitan, but confined to glasshouses in colder climates.

Suborder - Heteroptera

Examples:- 	Shield Bug or Stink-bug 	Ground Bug 	Bedbug 	Masked Assassin Bug or Flybug 	Water Boatman

Common Green Shield Bug – Palomena prasina

Description:-

	Adults about 12-14 mm long. 	Green in summer, except for the dark membranous tips of the forewings, but changes colour to brown in winter.

Biology:-

	Survives the winter as an adult, emerging from hibernation in spring when it regains its green colour. 	Feeds on various plants and sucks the juices of fruits. 	This and other Shield Bugs are also known as Stink-bugs, because they produce an irritant, smelly defensive secretion from glands in the thorax when disturbed or handled. Distribution:-

	Most of Europe, including the British Isles, and extending to temperate parts of Asia and North Africa.

Ex.:- Ground Bug - Lygaeus kalmii

Description:-

	Up to 10 mm long. Brightly coloured greyish-black and red. 	This species is a member of the family Lygaeidae, but it is very similar in general body shape to many green and brownish plant bugs belonging to the same family and to the families Coreidae (Squash Bugs) and Miridae (Capsid Bugs). 	Many of these plant bugs are important crop pests. Biology:-

	Ground Bugs are often found living in moss and plant debris or under stones and low bushes. 	Nearly all are plant-feeders, sucking the juices from leaves, fruits and seeds.

Distribution:-

	Throughout North America.

Ex.:- Common Bedbug - Cimex lectularius

Description:-

	Up to 8 mm long, coloured reddish-brown and wingless, with a greatly flattened body.

Biology:-

	Blood-sucking parasite of humans and also infests various domestic and zoo animals. 	The insects usually feed at night and hide in crevices or among bedding and clothing during the day. 	 Although the Bedbug's bite can be very irritating and annoying, there is no evidence that it regularly transmits any diseases. 	 The life cycle from egg to adult takes about 8 weeks, but may last much longer where conditions are unfavourable. 	The insects can survive several months without feeding.

Distribution:-

	Cosmopolitan, associated with human habitation. 	Because this order is so diverse, the habitats are widely varied, 	Hemiptera includes terrestrial and aquatic insects, and members of the order may be found on plants and animals. 	They are abundant worldwide. 5.	ORDER THYSANOPTERA - THRIPS (Thysanoptera, from Greek thusanos = fringe, pteron = wing)

	Minute, slender-bodied insects, often found in flowers. 	 Antennae rather short, with 6-9 segments, and placed close together on the front of the head. 	 Mouthparts for piercing and sucking. 	 Usually with a pair of very narrow wings, fringed both front and back with long hairs, but many species are wingless, and wing development is often very variable, so that even within a species there may be wingless, short-winged and fully-winged individuals. 	 The prothorax is distinct, but the other two thoracic segments are completely fused together. 	 Legs with very short, one or two segmented tarsi, ending in claws and a protrusible vesicle. 	 These vesicles act like small suction pads and enable the insect to walk on almost any kind of surface. 	 Cerci absent. Metamorphosis is simple, with two nymphal stages of the usual type, followed by two or three non-feeding, but mobile, 'pupal' stages. 	 Although thrips pass through these so called pupal stages during their development, their wings develop externally and they are clearly exopterygotes and not closely related to the other (endopterygote) Orders with pupal stag

Ex.:- Pea Thrips - Kakothrips robustus (= K. pisivorum)

Description:-

	Up to 2 mm long. Body mainly dark brown. 	 Forewings heavily tinged with brown, except at the base. 	 Hindwings almost transparent. 	Tarsi yellow 	Four wings, narrow, with few veins, fringed with long hairs. 	Mouthparts of sucking type, stout conical proboscis (beak). 	Short antennae, 4-9 segments. 	Tarsi 1-2 segments. 	Metamorphosis is intermediate between simple and complete. The first 2 instars have no external wings. 	The males and females look similar, but males a bit smaller. 	Several generations in a year. 	Plant feeders, flowers, leaves, fruits, twigs, buds. Few species feed on fungi, few are predaceous. 	Feeding destroys plant cells, they empty the cells which become silverish in color. If the attack is heavy, plant tissue will turn brown and dry up. 	Thrips are often vectors of diseases. 	The order Thysanoptera is divided in 2 suborders: Biology:-

	These thrips are responsible for the mottled silvery appearance of pea and bean pods. 	 The insects pierce and scrape the outer cells to reach the sap and the damaged, collapsed cells give the surface its silvery appearance. 	When they attack the flowers and young pods there can be considerable crop losses. 	 Adults emerge from pupae in the soil during late spring and early summer, and fly up on to the plants. 	Females lay eggs in flowers and the nymphs hatch after a week or so, feed for 2-3 weeks and then pupate in the soil to overwinter. 	 Usually only one generation a year.

Distribution:-

	Most of Europe, including the British Isles. REFERENCES :-

Ragumoorthi, K.N., Balasubramani, V., Srinivasan, M. R. and Nataraja, N. (2003): Insecta an introduction. A.E. Publications, Coimbature. pp 149-154 Mathur,Y. K. and Upadhyay, K.D. (2002): A text book of Entomology. A.P.H. Meerut, U.P. pp- 88-89. John R. Meyer (2005) Department of Entomology NC State University Grimaldi, D. and Engel, M.S. (2005). Evolution of the Insects. Cambridge University Press. ISBN 0-521-82149-5. Larry P.& Pedigo (2001) Entomology and pest management. Macmillan Publishing company pp101-130 Nayer K.K.,Anantha krishan T.N.,David B.V.(2005) General and Applied Entomology.A Mcgrow- Hill Publishing Company Limited –New Delhi,pp160-299

21:47, 29 April 2010 (UTC)21:47, 29 April 2010 (UTC)21:47, 29 April 2010 (UTC)