basic entomology with insect anatomy and taxonomy

this ppt provide information about basic or fundamental entomology

1. Course No. – ENTO-121 TITLE-FUNDAMENTALS OF ENTOMOLOGY Dr. Anita Sharma Asstt . Professor (Entomology)

2. Entomology- Greek word ( Entomon = Insect; Logos = Study) It is the branch of zoology or biological science that deals with the study of insects . INTRODUCTION Insect : - The insects are the tracheate arthropods in which the body is divided in to head, thorax and abdomen possessing 2 pairs of wings. 3 pairs of working legs. 1 pair of antennae. Segmented body. Having complete and incomplete metamorphosis.

3. Insect is Greek word = Cut in pieces or segmented. Insects belong to the Phylum Arthropod a ( Artho = jointed, Poda = Legs) which is the biggest phylum of kingdom Animalia . More than three quarters of the animals on earth are arthropods, and most of these are insects. Kingdom Animalia is classified into twelve phyla. INTRODUCTION

4. Study and use of insects in crime investigations is known as Forensic Entomology . Study of insects related to live stock and veterinary animals is known as Veterinary Entomology . Study of insects in relation to Human beings is known as Medical Entomology . Study of insects in relation to Agriculture is known as Agriculture Entomology Branches of Entomology

5. Topic -1, HISTORY OF ENTOMOLOGY IN INDIA Aristotle (384-322 B.C.)– Father of biological classification . First person grouped insects in winged and wing less groups. He gave the terms like Coleoptera and Diptera . Carolus Linnaeus (1758)– Father of Taxonomy . William Kirby considered as “Founder of Entomology ” because of his significant role in Entomology in the world. He published a book “ An Introduction to Entomology” (1815-1826). Snodgrass R. E. (1875)– referred as a Father of Insect Morphology . He wrote book - Principles of Insect Morphology. Mithan Lal Runwal (1908)– Outstanding work on termites/ white ants. Contributions to ecology, embryology and locust. 1940 - Dr. T.V. Ramakrishna Ayyar published the book " Handbook of Economic Entomology " which met the long felt need of the students of Agriculture and agricultural scientists as well and also known as “Father of Indian Entomology”. Dr.S.Pradhan (1969) - Wrote a "Insect Pests of Crops" and Father of Modern Applied Entomology in India.

6. History of Entomology in India 1758 - 10th edition of Systema Naturae by Linnaeus with only 12 Indian insects which was the earliest record. 1779 - Dr. J.G. Koenig - Medical Officer initiated the work on Indian insects on scientific lines. He also published a special account of the termites of Thanjavu r District. 1782 - Dr. Kerr Published on account of lac insect. 1785 - Asiatic Society of Bengal started in Calcutta and many papers were published in the Societys publications. 1790 - Roxburgh (Botanist) published a detailed account of lac insect. 1791 - Dr. J. Anderson issued a monograph on Cochineal scale insects 1800 - Buchanan ( Traveller ) wrote on the cultivation of lac in India and on sericulture in some parts of South India. Denovan published Natural History of Insects which was the first contribution on the insects of Asia and was revised in 1842 by West Wood. 1875 - Foundation of the Indian Museum at Calcutta

7. 1883 - Bombay Natural History Society was started. After the foundation of these two organisations scientific studies received greater attention in India. Numerous contributions of Indian insects were published in the Journal of the Bombay Natural History. 1893 - Rothney published on Indian Ants (earliest record of biological pest control in India) i.e. White ants attach on stationary items was kept free by red ants. 1897 - Bingham's issued volumes on "Hymenoptera ' (Ants, bees and wasps). Since than volumes on other groups of insects like Coleoptera (beetles), Hemiptera (bugs), Odonata ( dragenfly and damselfly), etc., were published. 1889 - Indian Museum, Calcutta published the Indian Museum Notes in five volumes. 1901 - (Lionel de Nicevelle ) posting of the first entomologist to the Government of India. 1905 - Establishment of Imperial Agricultural Research Institute at Pusa (Bihar). Maxwell Lefroy became first Imperial Entomologist of Govt. of India. 1906 - “Indian Insect Pests” & “Indian Insect Life” Books by Professor Maxwell . Subsequently State Governments also took up entomological work. 1914 - T.B. Fletcher, the first Government Entomologist of Madras State , published his book "Some South Indian Insects".

8. 1916 –”Indian Forest of Economic Importance: Coleoptera ; was published by the first Imperial Forest Entomologist E.P. Stebbing ”. 1921 - Indian Central Cotton Committee to investigate on pests of cotton. 1925 - Indian Lac Research Institute. 1934- Hem Singh Pruthi as Imperial Entomologist, start ‘Entomological Society of India ’ in 1938. Afzal Hussain was the first president of the society and VC were HS Pruthi and Ayyar . 1940 - Dr. T.V. Ramakrishna Ayyar published the book " Handbook of Economic Entomology " which met the long felt need of the students of Agriculture and agricultural scientists as well and also known as “Father of Indian Entomology”. 1968 - Dr. M.S. Mani's "General Entomology" 1969 - Dr. H.s. Pruthi's "Textbook of Agricultural Entomology". Dr. Pradhan's "Insect Pests of Crops“ 1946 - Government of India started the "Directorate of plant protection, quarentine and storage.". 1960 - "The Desert Locust in India" monograph by Y.R. Rao . 1969 - "The monograph on Indian Thysanoptera " by Dr. T.N. Ananthakrishnan

9. 1912– Plant Quarantine Act. 1914– Destructive Insects and Pests Act ( DIPA ). 1916– Imperial Forest Research Institute at Dehradun . 1925– Indian Lac Research Institute started at Ranchi. 1937– A laboratory for storage pests was started at Hapur , U.P. 1937- Establishment of Entomology division at IARI New Delhi. 1939– Locust Warning Organization established at Jodhpur. 1946– ‘Directorate of Plant Protection, Quarantine & Storage at Faridabaad . 1968– ‘Central Insecticide Act’. Institutes/Organizations

10. NCIPM , New Delhi- (National Centre for Integrated Pest Management - 1988). PDBC , Bangalore- (Project Directorate of Biological Control -1993). NBAIR -National Bureau of Agricultural Insect Resources and formerly it is a NBAII, Bengalore in 1957. CIB , Faridabad – Central Insecticide Board. NPPTI , Hyderabad– National Plant Protection Training Institute. Entomological Institutes

11. FACTORS FOR INSECTS ABUNDANCE Measures of dominance 1. More number of species : In the animal kingdom more than 85 per cent of the species belongs to insect group. Total number of insects described so far is more than 9 lakhs . 2. Large number of individuals in a single species: e.g., Locust swarm comprising of 10 9 number of individuals, occupying large area. 3. Great variety of habitats: Insects thrive well under varied conditions. 4. Long geological history : Insects were known to occupy this earth for more than 350 million years, which is a good track record. This has given the insects great variety of adoptions under different conditions.

12. Reasons for dominance Capacity for flight: Insects posess wings, which is the lateral extension of exoskeleton. Insects are the earliest animals and the only flying invertebrates. Flight is used for the following purpose- To seek food, mate, shelter and oviposition sites To colonize in a new habitat and also to exchange habitat. To escape from enemies and unfavourable conditions. To migrate (i.e. for long distance travel e.g. Locusts) Adaptability or Universality: Insects are the earliest groups to make their life on the earth and to occupy vast habitats of soil and water. i . Found in wide range of climatic conditions, from -50 ñ C to 40 ñ C. ii. Psilopa petroli found in crude petroleum well. iii. Ephydra fly living in great salt lake. iv. Every flowering plant providing food for one or many Phytophagous insects. v. Even the decomposing materials serving as food for many Saprophagous insects. vi. Many Carnivorous insects are parasitic on other animals and insects.

13. 3. Size : Majority of insects are small conferring the following physiological and ecological advantages. i . Less space, food, time and energy requirements for development and sustaining life. ii. Energy Utilization maximum. iii. Less gravitational effect. iv. Muscular action and tracheal respiration more effective. v. Easy escape from enemies. 4. Exoskeleton: Insect body is covered with an outer cuticle called exoskeleton which is made up of a cuticular protein called Chitin. This is light in weight and gives strength, rigidity and flexibility to the insect body. Uses: i.Act as external armour ii.Provides space for muscle attachment iii.Prevents water loss

14. 5. Resistance to desiccation : Insects minimise the water loss from their body surface through the following processes. I. Prevention of water loss: i . Lipids and polyphenols present in the Epicuticle acts as water proofing. ii. Was layer with closely packed wax molecules prevents escape of water. iii. Spiracles are closed to prevent water loss. iv. In the egg stage shell development prevents water loss and desication of inner embryos. II. Conservation of water i . Capable of utilizing metabolic water ii. Rectal resorption of water from faeces . iii. Terrestrial insects use less quantity of water to remove the nitrogenous waste (Uric acid) which is water insoluble. 6. Tracheal system of respiration: This ensures direct transfer of adequate oxygen to actively breathing tissues. Spiracles through their closing mechanism admit air and restrict water loss.

15. 7. Reproductive potential: Reproductive potential of insect is high due to the following reasons: i Egg laying capacity (fecundity) is high. e.g., Queen termite lays 6000 - 7000 eggs per day for 15 long years. ii. Development period is short. e.g., Corn aphid produces 16 nymphs per female which reaches the adulthood within 16 days. There by one generation is completed within a short period of 16 days, which favours greater genetic changes in the insect population, like quicker development of insecticide resistant strains. iii. Careful selection of egg lying sites and protection of eggs. iv. Exhibits parental care like progressive provisioning (e.g. bees) and mass provisioning (e.g. Wasps) v. Presence of special types of reproduction other than oviparity and viviparity . * Polyembryony : Development of many individuals from a single egg. e.g. parasitic wasps. * Parthenogenesis : Reproduction without male or without fertilization, e.g. aphids * Paedogenesis : Reproduction by immature stages. e.g. certain flies.

16. 8. Complete metamorphosis: More than 82 per cent of insects undergo complete metamorphosis ( Holometabolous insects) with the following four stages. i . Egg: Inactive, inexpensive, inconspicuous and embryo develops inside. ii. Larva: Active, feeds, digests, grows and store food. iii. Pupa: Inactive, internal reorganisation and resist adverse conditions. iv. Adult: Active, reproduce and disperse. As the larval and adult food sources are different, competition for food is less. 9. Defense mechanisms: By using the following defense mechanisms, insects escape from the enemies to increase their survival rate. i . Behavioural : Thanatosis - insects pretends as if dead. e.g. some beetles. ii. Structural e.g. hardened forewings of beetles known as elytra protect the beetles from predation of birds. iii. Colourational : Presence of protective colours . e.g.Stick insects iv. Chemical : Presence of defensive chemicals. e.g. Bees producing venom 10. Hexapod locomotion: Insects uses 3 legs at a time during locomotion, while the remaining 3 legs are static, which gives greater stability.

17. POSITION OF INSECTS IN ANIMAL KINGDOM

18. POSITION OF INSECTS IN ANIMAL KINGDOM AND ITS RELATIONSHIP WITH OTHER ARTHROPODA Classification: 7 classes. Phylum : Arthropoda Classes : 1. Onychophora (claw bearing)e.g. Peripatus , has similarities with arthropoda like antenae , open circulatory system, walking legs with claw and tracheal system. 2. Crustacea ( Crusta - shell)e.g. Prawn, crab, wood louse 3. Arachnida ( Arachne - spider)e.g. Scorpion, spider, tick, mite 4. Chilopoda ( Chilo - lip; poda - appendage)e.g. Centipedes (carnivorous) 5. Diplopoda ( Diplo - two; poda - - appendage)e.g. Millipede ( scavengers) 6. Trilobita (an extinct group)- The dominant arthropodes in the early Paleozoic seas (many million ago) 7. Hexapoda or Insectae.g . Insects.

19. Characters of the Phylum Arthropoda : ( Arthro -joint, poda -foot) i . Segmented body ii. Segments grouped into 2 or 3 regions known as Tagmosis iii. Renewable chitinous exoskeleton iv. Grow by moulting v. Bilateral symmetry vi. Body cavity filled with blood- Haemocoel vii. Tubular alimentary canal with mouth and anus viii. Dorsal heart with ostia ix. Dorsal brain with ventral nerve cord x. Striated muscles xi. No cilia xii. Paired segmented appendages

20. Insect body wall – Integument/Exoskeleton External covering – ectodermal in origin Rigid, flexible, lighter, stronger and variously modified Insect Integument: Structure and Function

21. Consists of 3 layers : Structure Integument Cuticle Epidermis Basement membrane

22. Outer non-cellular layer – has 2 sub-layers Epicuticle : outer most layer – very thin – devoid of chitin Differentiated into 5 layers: Cement layer – outer most layer – made of lipid and tanned protein – protects wax layer. Wax layer – contains closely packed wax molecules – prevents desiccation Cuticulin – Non-chitinous polymerised lipoprotein layer – barrier to ions Outer Epicuticle Inner Epicuticle (It contain wax filaments) Cuticle. ...

23. Procuticle – divided into 2 – Outer exocuticle & Inner Endocuticle . Exocuticle : Outer layer – much thicker – composed of Chitin & Sclerotin – Dark and rigid Endocuticle – Inner layer – thickest layer – made of chitin & Arthropodin – Colourless, soft and flexible. Epidermis: Inner unicellular layer resting on basement membrane – Functions: Cuticle secretion Digestion and absorption of old cuticle Wound repairing Gives surface look

24. Composition .... Chitin: Main constituent of cuticle Nitrogenous polysaccharide and polymer of N- acetylglucosamine . (water insoluble and soluble in acids, alkalies and organic solvents) Arthropodin : Untanned cuticular protein (water soluble). Sclerotin : Tanned cuticular protein (water insoluble). Resilin : Elastic cuticular protein – for flexibility of sclerites .

25. Cuticular in growth of body wall – provide space for muscle attachment. 2 types: Apodeme – hollow invagination of body wall (ridge like) Apophysis – Solid invagination of body wall (spine or fingure like) Endoskeleton. ..

26. 31

27. Clothing hairs, plumose hairs. e.g. Honey bee. Bristles. e.g. flies 32

28. Scales - flattened out growth of body wall e.g. Moths and butterflies 33

29. Glandular seta. et. caterpillar 34

30. Sensory setae - associated with sensory neuron or neurons 35

31. Seta - hair like out growth (Epidermal cell generating seta is known as Trichogen , while 36

32. 37 Multicellular e.g. Spur - movable structure Spine - Immovable structure

33. GLANDS Cuticular glands are either unicellular or multicellular. Following are some of the examples . i . Wax gland - e.g. Honey bee and mealy bug ii. Lac gland - e.g. Lac insects iii . Moulting gland secreting moulting fluid. iv . Androconia or scent scale - e.g.moth v . Poison gland - e.g. slug caterpillar 38

34. Wax gland - e.g. Honey bee and mealy bug 39

35. . Lac gland - e.g. Lac insects 40

36. Moulting gland secreting moulting fluid 41

37. Poison gland - e.g. slug caterpillar 42

38. Functions of Body wall i . Acts as external armour and strengthen external organs like jaws and ovipositor ii . Protects the organs against physical aberation , injurious chemicals, parasites, predators and pathogen. iii . Internally protects the vital organs, foregut, hindgut and trachea. iv . Provides space for muscle attachment and gives shape to the body. v . Prevents water loss from the body. vi . Cuticular sensory organs helps in sensing the environment. vii . Cuticular pigments give colour. 43

39. MOULTING ( Ecdysis ) Ecdysis Periodical process of shedding the old cuticle accompanied by the formation of new cuticle is known as moulting or ecdysis . The cuticular parts discarded during moulting is known as Exuvia . Moulting occurs many times in an insect during the immatured stages before attaining the adult-hood. The time interval between the two subsequent moulting is called as Stadium and the form assumed by the insect in any stadium is called as Instar . 44

40. Steps in moulting 1. Behaviroual changes: Larva stops feeding and become inactive . 2. Changes in epidermis: In the epidermis cell size, its activity, protein content and enzyme level increases. Cells divide miotically and increases the tension, which results in loosening of cells of cuticle . 45

41. 3. Apolysis : Detachment of cuticle from epidermis 4. Formation of Sub cuticular space 5. Secretion of moulting gel in the sub cuticular space which is rich with chitinase and protease. 6. New epicuticle formation: Lipoprotein layer ( cuticulin ) is laid over the epidermis. 46

42. 7. Procuticle formation: Procuticle is formed below the epicuticle. 8. Activation of moulting gel: Moulting gel is converted into moulting fluid rich in enzymes. This activates endocuticle digestion and absorption. 9. Wax layer formation: Wax threads of pore canals secrete wax layer. 10. Cement layer formation : Dermal glands secretes cement layer ( Tectocuticle ). 47

43. 11. Moulting : This involves two steps   i . Rupturing of old cuticle: Insect increases its body volume through intake of air or water which enhances the blood flow to head and thorax. There by the old cuticle ruptures along predetermined line of weakness known as ecdysial line ii. Removal of old cuticle: Peristaltic movement of body and lubricant action of moulting fluid helps in the removal of old cuticle. During each moulting the cuticular coverings discarded are the cuticular of legs, internal linings of foregut and hindgut and trachea . 12.Formation of exocuticle : The upper layer of procuticle develops as exocuticle through addition of protein and tanning by phenolic substance . 13.Formation of endocuticle : The lower layer of procuticle develops as endocuticle through addition of chitin and protein. This layer increases in thickness. 48

44. Control of Moulting: It is controlled by endocrine gland like prothoracic gland which secrete moulting hormone. Endocrine glands are activated by prothoracico -tropic hormones produced by neurosecretory cells of brain. 49

45. Moulting: Shedding of old cuticle accompanied by formation of new cuticle is called Moulting or Ecdysis . Detachment of cuticle from the epidermis is apolysis The time interval between two moults is called a stadium The formation of an insect during a stadium is called an instar The cast off skin by an insect is called as exuviae Chitin which makes up the exo -and endocuticle is a nitrogenous polysaccharide formed from long chains N-acetyl D-glucosamine units ( C 8 H 13 O 5 N) n 50

46. BODY SEGMENTATION OF INSECT & INSECT HEAD

47. Cockroach and Grasshopper is a typical insect as it possesses all important characters of class insect. In general, insect body is divided in to a series of rings or segments are known as “ somites ” or “ metameres ”. The type of arrangement of these body segments in embryonic stage is known as primary segmentation while in adult insects is known as the secondary segmentation.

48. Insect body is divided in to three regions or tagmata namely head, thorax and abdomen. This grouping of body segments in to regions is known as tagmosis . Head consists of 6 segments i.e., mouthparts, compound eyes, simple eyes ( ocelli ) and a pair of antennae. Thorax consists of 3 segments i.e. prothorax , mesothorax and metathorax . Meso and metathorax are together known as pterothorax . All the three thoracic segments possess a pair of legs and meso and meta thorax possess one pair of wings . Abdomen has 11 segments with genital appendages on 8th and 9th segments. The insect body generally consists of 20 segments.

49. Fig. General Organization of Insect Body

50. INSECT HEAD

51. It is the foremost part in insect body consisting of 6 segments that are fused to form a head capsule. Labral , antennary, ocular, mandibular , maxillary and labial segments. The head segments can be divided in to two regions i.e. procephalon and gnathocephalon (mouth). Head is attached or articulated to the thorax through neck or cervix. Head capsule is sclerotized and the head capsule excluding appendages formed by the fusion of several sclerites is known as cranium. Inside the head, an endoskeletal structure called the tentorium which give supports to the brain, and provides a rigid origin for muscles of the mandibles and other mouthparts. Head is concerned with feeding and sensory perception.

52. Types of head position The orientation of head with respect to the rest of the body varies. According to the position or projection of mouth parts the head of the insect can be classified as: (a) Hypognathous (Hypo–Below and Gnathous –Jaw) The head remain vertical and is at right angle to the long axis of the body and mouth parts are ventrally placed and projected downwards. This is also kwown as Orthopteroid type. Eg : Grass hopper, Cockroach.

53. ( b) Prognathous : (Pro– infront and Gnathous – Jaw) The head remains in the same axis to body and mouth parts are projected forward. This is also known as Coleopteroid type. Eg : beetles

54. (c) Opisthognathous : ( Opistho – behind and Gnathous Jaw) It is same as prognathous but mouthparts are directed backward and held in between the fore legs. This is also kwown as Hemipteroid or Opisthorhynchous type. Eg : bugs, Mosquito

55. SCLERITES AND SUTURES OF HEAD The head capsule is formed by the union of number of sclerites or cuticular plates or areas which are joined together by means of cuticular lines or ridges known as sutures or any of the large or small sclerotized /harden areas of the body wall. These sutures provide mechanical support to the cranial wall. Suture The sclerites separated from each other by means of thin impressed line called suture. (Sometimes referred as a sulcus ).

56. Generally insect possess the following sclerites : Vertex: It is the top portion of epicranium which lies behind the frons or the area between the two compound eyes. 2. Clypeus: It is situated above the labrum , separated by fronto -clypeal suture & also separated from gena by clypogenal suture. 3. Frons : It is unpaired, facial part of the head capsule lying between the arms of epicranial suture. Facial area below the vertex and above clypeus 4. Gena : It is the area extending from below the compound eyes to just above the mandibles. It is separated from frons by frontoganal suture and from clypeus clypogenal suture.

57. 5. Occiput : Cranial area between occipital and post occipital suture . 6. Post occiput : It is the extreme posterior part of the insect head that remains before the neck region. 7. Occular sclerites : These are cuticular ring like structures present around each compound eye. 8. Antennal sclerites : These form the basis for the antennae and present around the scape .

58. Fig. Anterior view or face view

59. The common sutures present in head are: Clypeolabral suture: It is the suture present between clypeus and labrum . 2. Clypeofrontal suture or epistomal suture: The suture present between clypeus and frons . 3. Epicranial suture: It is an inverted ‘Y’ shaped suture distributed above the facial region extending up to the epicranial part of the head. 4. Occipital suture: It is ‘U’ shaped or horseshoe shaped suture between epicranium and occiput .

60. 5. Genal suture: It is the sutures present on the lateral side of the head i.e. gena . 6. Post occipital suture: It is the only real suture in insect head. Posterior end of the head is marked by the post occipital suture to which the sclerites are attached. As this suture separates the head from the neck, hence named as real suture. 7. Occular suture: It is circular suture present around each compound eye. 8. Antennal suture: It is a marginal depressed ring around the antennal socket.

61. Insect Thorax And abdomen

62. Thorax Middle tagma Three segmented - pro, meso and meta Meso and meta thorax with wing are called as Pterothorax Thorax is made of three scleritic plates 1. dorsal body plate - Tergum or Nota 2. ventral body plate ( Sterna ) 3. lateral plate ( Pleura )

63. Thoracic nota 3 segments - pronotum , mesonotum & metanotum respectively Pronotum - undivided & Saddle shaped in grass hopper, Shield like in cockroach Pterothoracic notum - h ave 3 transverse sutures ( Antecostal , Pre scutal and Scuto-scutellar ) & 5 tergites ( Acrotergite , Prescutum , Scutum , Scutellum and Post- scutellum )

64. Thoracic sterna Vental body plate - prosternum , mesosternum and metasternum Made up of a segmental plate called Eusternum and a intersternite called Spinasternum Eusternum - made of three sclerites - presternum , basisternum and sternellum

65. Thoracic pleura Lateral body wall between notum & sternum Selerites of pleuron is called as pleurites fuse to form Pleural plate Pleural plate is divided into anterior episternum and posterior epimeron by Pleural suture Pterothoracic pleuron provides space for articulation of wing and Two pairs of spiracles are also present in the mesopleuron and metapleuron .

66. ABDOMEN Third and posterior tagma This tagma is made up of 9-11 Uromeres (segments) and is highly flexible abdominal segments are interconnected by a membrane called conjunctiva Each abdominal segment is made up of only two sclerite 1. Tergum 2. Sternum

67. ABDOMEN Eight pairs of spiracles in - first eight abdominal segments in addition to a pair of tympanum in the first abdominal segment Eight and ninth segments - female genital structure Ninth segment - male genital structure . Cerci