农大昆虫学课件-昆虫分类（四）.ppt

1、纺足目 EMBIOPTERA,Common Names: web-spinners, foot-spinners足丝蚁 Distribution: Tropics and warm temperate regions DescriptionSuperficially, embiopterans or web-spinners resemble termites. However, web-spinners do not utilise solid wood (such as fallen logs) as a food source although they do attack plant

2、debris. They have kidney-shaped (reniform) compound eyes but simple eyes (ocelli) are absent. Body colour is generally dull brown. The mandibles are well developed. Most winged species have two pairs of wings, both of which are membranous, soft and flexible. Females are always wingless but some spec

3、ies do not possess winged males. In some species the males may or may not be winged. The abdomen is long and soft with 10 well defined segments although there may be rudimentary traces of an eleventh segment.The characteristic which gives rise to this insects common name is the swollen first tarsal

4、segment of each foreleg which contains silk glands. The insects construct silk galleries through the leaf mould, litter or moss in which they are living using silk from the leg glands. Even newly emerged nymphs are able to secrete silk and build galleries for themselves. NymphThere is no metamorphic

5、 cycle of egg-larva-pupa-adult. The insect emerges from the egg as a miniature of the adult (nymph). But without wings if a male of a winged species. Nymphs increase in size and maturity by successives moult (paurometamorphosis). MembersWeb-spinners, foot-spinners, embiids. FoodWeb-spinners are scav

6、engers of plant material. Most food comprises moss, bark and dead leaves from the forest floor. After mating, males do not feed and may then be consumed by the females. ImportanceNo known economic importance. The presence of web-spinners in the food chains of ecosystems implies that the insects are

7、a part of the forest litter re-cycling system. More than 300 species are recorded in the world ，only 6 species recorded in China.,蛩蠊目 GRYLLOBLATTODEA,Common Name: rock crawlers，蛩蠊 Distribution: Northern Hemisphere DescriptionGrylloblattids are restricted to western North America and central to easte

8、rn Asia. The twenty known species are particularly tolerant to cold climates and high altitude. Adults are soft-bodied, pale, finely haired, wingless and possess well developed mandibles. The compound eyes are either absent or reduced in size. Grylloblattids lack organs for the production or recepti

9、on of sound. Two long, flexible and segmented filaments (cerci) project from the apex of the abdomen. An ovipositor strongly projects from the females abdomen. Most species are active by both night and day. Many are found in caves, snow-melt areas and similarly cool regions. NymphThere is no metamor

10、phic cycle of egg-larva-pupa-adult. When juveniles hatch from the eggs, they resemble small versions of the adults (nymphs). Through successive moults nymphs reach adult maturity (paurometamorphosis). MembersRock crawlers and ice crawlers. FoodGrylloblattids are scavengers on dead plant or animal ma

11、terial. ImportanceNo known economic importance. Their importance is as a component in cave or alpine ecosystems. Only one species recorded in China.,革翅目 DERMAPTERA,Common Name: earwigs, 蠼螋, 搜夹子 Distribution: Cosmopolitan DescriptionEarwigs are elongate, often rather flattened insects with well devel

12、oped mandibles. The distinguishing characteristic of this order is the presence of forceps at the end of the abdomen. Forceps are used by earwigs in a threatening display when disturbed. However, they are harmless to humans and are only capable of producing a sharp pinch. The terminal forceps may be

13、 used to carry insect prey or may be used during mating to grasp the partner. Earwigs may or may not possess wings. Winged species have forewings modified into small, tough covers (the tegmina). Hind wings are membranous, semicircular and are folded in fan form under the tegmina. Hind wings can also

14、 be folded across so that the whole wing is packed into a very small space. Compound eyes may be small, large or absent, and simple eyes (ocelli) are always absent. NymphNo comparable stages to caterpillar and pupa occur in earwigs. The nymphs emerge from the eggs and resemble miniatures of the adul

15、ts. Nymphs moult several times before reaching adult size and maturity (paurometamorphosis). Earwigs display maternal activity. The mother guards the egg clutch and young offspring until they are able to fend for themselves. FoodMost species feed on dead plant material. However, some species attack

16、living plants. Animal material will be eaten if available and earwigs will readily consume dead insects as food. A few specialised earwigs are parasites of bats and rodents. ImportanceFew earwigs are of economic importance. In Australia, the introduced European earwig (Forficula auricularia) causes

17、considerable damage to orchards and garden ornamentals where it destroys both fruit and flowers. Australia is remarkable in possessing a giant earwig, Titanolabis colossae, which occurs in rainforest litter and can be 4-5 cm in length.,襀翅目 PLECOPTERA,Common Name: stoneflies 石蝇、襀翅虫 Distribution: Cosm

18、opolitan DescriptionStoneflies are soft bodied insects that generally have two unequal pairs of membranous, intricately veined wings. However, there are some wingless species. The forewings are smaller than the hind wings and are often longer than the abdomen of the insect. Adult insects have large

19、compound eyes with two or three simple eyes (ocelli). The antennae are long and composed of short, straight segments (filiform). The adult stage has mandibles but these are often reduced. In some species they may be functionless as the adult insect has not been observed to feed. Generally, there are

20、 two appendages at the end of the abdomen (cerci). NaiadThe juveniles emerge from the eggs as miniature replicas of the adults (nymphs) but without wings. Nymphs mature through a series of moults, sometimes as many as 33. The nymphs are aquatic and possess gills as a fringe along the abdomen (hemime

21、tamorphsis). The nymphs crawl about over the beds of fast flowing streams, although they can swim if necessary. Stoneflies are very quickly affected by pollution as they are unable to tolerate even minor levels of contaminants. FoodThe nymphs may feed on plants, animals and detritus, or be restricte

22、d solely to plants. Some nymphs are predators on small aquatic life. Adults feed on algae, lichens, plants or even rotten wood. ImportanceNo known importance apart from their presence in the food-chains of freshwater communities. The stoneflies may be useful components in fish food-chains. More than

23、 2300 species are recorded in the world ，more than 300 species recorded in China.,缺翅目 ZORAPTERA,Common Names: 缺翅虫 Distribution: Tropical and warm temperate regions; absent from Australia DescriptionZorapterans are quite small insects (less than 3 mm long) and resemble termites. The antennae resemble

24、 a chain of beads (moniliform). Compound and simple eyes (ocelli) are present in winged species but they are absent in wingless species. Mandibles are present and well developed. If wings are present, the hind wings are smaller than the forewings. The venation in both pair of wings is reduced. Wings

25、 are shed in a manner similar to ants and termites.The insects are gregarious and occur in forest litter, rotten wood or close to termite colonies. NymphThe juveniles emerge from the eggs as miniatures of the adults (nymphs) but have slightly different structures depending upon whether or not wings

26、will be developed in the adult （paurometamorphosis). FoodZorapterans consume fungi and small arthropods although the latter is uncertain. ImportanceNo known importance apart from membership in the food chains of any ecosystem.,缨翅目 THYSANOPTERA,Common Name: thrips 蓟马 Distribution: Cosmopolitan Descri

27、ptionThrips feed on the sap of plants. The distinguishing characteristic of thrips is the possession of two pairs of fringed wings. Compound eyes are well developed and three simple eyes (ocelli) may be present in winged forms. The antennae are composed of short straight segments (filiform). The man

28、dibles and mouthparts are highly modified for rasping and sucking and as a result the left mandible has become a stylet while the right mandible has almost disappeared (atrophied). The winged forms are capable of weak flight, but can cover large distances when assisted by the wind. NymphFemales lay

29、eggs directly into plant tissues or crevices in vegetation. The emerging juveniles resembles the adults but are wingless (nymphs). The nymphs mature by successive moults but some of these stages may involve considerable resting when large amounts of internal tissue alteration takes place （hyperpauro

30、metamorphosis）. Female thrips are diploid but male thrips (if they are present) are haploid as they are produced from unfertilised eggs. Some species of thrips inhabit litter while others manufacture galls in which they have complete protection while feeding. FoodThrips feed on plant sap obtained by

31、 rasping at the vegetation surface and sucking up the resulting fluid. Litter inhabiting thrips consume fungi. ImportanceThrips are of immense importance as pests in horticulture. Some crops subject to thrips damage are onions, tobacco, pears, apples, bananas and citrus, but there are many more. Num

32、erous flowering plants are also attacked. When fruit is attacked it is rendered valueless for market due to the loss of juices from the fruit together with the brownish blotches produced by the thrips method of feeding. The browning of roses by thrips infestations is well known to gardeners.,同翅目 Hom

33、optera,Common Names: leafhoppers, cicadas, aphids, scale insects.蝉、沫蝉、叶蝉、角蝉、蜡蝉、蚜虫、粉虱、木虱、介壳虫 Distribution: Cosmopolitan DescriptionHomoptera may be hard or soft bodied, and they may be smooth or covered with hairs or spines. Many species cover their bodies with waxy secretions, which can form filamen

34、ts longer than the insects body. Most Homoptera have two pairs of wings, but some have only one pair, and some are wingless. The wings usually have a membranous texture and are held tentlike over the abdomen.The Homoptera have piercing and sucking mouthparts that are in the form of a beak, similar t

35、o the Hemiptera. This beak arises from the hind part of head, which is bent downward. Their antennae are short and hairlike, but are absent in females of some scale insects.The abdomens of some Homoptera have different structures. The first segment of the abdomen may have a sound producing organ, as

36、 in cicadas. Aphids have a pair or short tubelike projections at the back of their abdomens. These structures are called cornicles and are used for secreting defensive chemicals. The scale insects are unusual in that the females do not have wings and often do not have legs. Males generally have legs

37、, but they only have one pair of wings, and they lack mouthparts. The developing nymphs of many scales secrete a waxy covering that is hard and scalelike or soft and cottony. . In the remainder of the order, the wings are held over the abdomen rather like the two sides of a house roof (cicadas, etc.

38、). NymphThe Homoptera generally have incomplete metamorphosis (egg-nymph-adult) （paurometamorphosis). Some Homoptera, such as aphids, do not lay eggs, but give birth to living young （viviparous）. Whiteflies (family Aleyrodidae) have a resting stage, similar to a pupa, between the active nymph and ad

39、ult stages （hyperpaurometamorphosis）. Memberscicadas, leaf hoppers, spittlebugs, aphids, psyllids or lerp-insects, scale insects and whiteflies. FoodMembers of the order Homoptera are plant feeders and are found wherever plants grow. Some Homoptera, such as cicadas, live high in the tops of trees. T

40、here are some scale insects that feed on the roots of plants. Some species can be found in ants nests or in rotten logs. Many Homoptera are found in greenhouses or fields where crops are cultivated. There are no Homoptera that live in water. ImportanceHomoptera are among the most abundant herbivores

41、 found in terrestrial habitats. Many species are pests of cultivated plants. Aphids and leafhoppers are important carriers of plant diseases. Some Homoptera have been beneficial to man. Aphids produce many offspring that provide food for other insects. Shellac and varnish have been made from the lac

42、 insects, Laccifer lacca, which occurs in India. Certain scale insects provide pigments used in the making of dyes. And, of course, could we enjoy the dog-days of summer without the wondrous buzzing song of the cicada.,半翅目 HEMIPTERA,Common Names: true bugs,蝽类，椿象，臭屁虫 Distribution: Cosmopolitan Descri

43、ptionBugs possess piercing-sucking mouthparts in a simple tube (rostrum) formed by modification of the insects lower lip (labium). Inside the tube, modified mandibles form canals which allow an upward flow of liquid food and a downward flow of saliva. The modified mandibles are called stylets. Often

44、 the rostrum is held under the head but is brought forward during feeding. Compound eyes are usually present and well developed; simple eyes (ocelli) may be present. Antennae may be short with only a few segments, or well developed and more or less filiform. Most species possess two pairs of wings,

45、but some have only one pair and a few species have none. The Order name describes a character of the many bugs in which the front pair of wings is modified so that the basal half of each wing is hardened (sclerotised) to form a protective cover (a hemelytra). As the wings of bugs are folded flat on

46、the abdomen, this makes the insect appear as if half of each of the forewings is missing. True bugs often produce a repellent odour - used for defence - from a specialised gland. NymphBugs emerge from eggs as wingless miniatures of the adults (nymphs) and mature by successive moults （paurometamorpho

47、sis). MembersBugs, water striders, water scorpions, water bugs, water boatmen FoodBugs feed on liquid obtained from plants or animals including man. Any part of the plant may be used as food: leaves, stems, fruits or roots. Blood is consumed by some species, while others consume insect body fluid. I

48、mportanceThe plant feeding bugs are considered serious pests in agriculture. Some species are important predators。,啮虫目 PSOCOPTERA,Common Names: booklice, barklice， 啮虫或书虱 Distribution: Cosmopolitan DescriptionPsocids are tiny insects that are extremely common but so small that they are frequently ove

49、rlooked. Wings may be present, reduced or absent. If present, wings are membranous with small numbers of veins. Wings are held roof-wise over the insects abdomen when at rest. The front and rear wings are coupled together to form a single surface during flight. Winged species have large compound eye

50、s and three simple eyes (ocelli) but the simple eyes are absent in wingless species. Mandibles are well developed. The antennae are long and composed of short, straight segments (filiform). NymphThe eggs are laid in small clusters and covered with a sheet of fine silk web. Juveniles emerge from the

51、eggs as wingless miniatures of the adults (nymphs) and attain maturity through a series of moults （paurometamorphosis). FoodPsocids feed on fungi (hyphae and spores), lichens, algae, bark and plant debris. ImportanceGenerally of little human impact, the importance of booklice is only noted under unu

52、sual circumstances. Booklice may live among old papers in human dwellings and can cause considerable damage by their feeding actions. They scrape off the surface fibres of the sheets of paper. Some species have caused considerable damage to both herbarium and museum specimens. In nature, the booklic

53、e form part of the foodwebs of ecosystems.,虱目 PHTHIRAPTERA,Common Name: lice Distribution: Cosmopolitanh DescriptionLice are obligate ectoparasites (unable to live anywhere else except on the skin of another organism). They are found on all bird species and almost all mammals except bats. All species of lice are wingless, the eyes are either absent or reduced and the antennae are either greatl