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PRACTICAL ENTOMOLOGY (BIO. 359) FACULTY OF SCIENCE DEPARTMENT OF BIOLOGY PRACTICAL COURSE ENTOMOLOGY (BIO. 359) ﺇﺑﺮﺍﻫﻴـﻢ ﻋﺒﺪ ﺍﳊﻤﻴـﺪ ﺇﺑﺮﺍﻫﻴـﻢ ﺭﺯﻕ/.ﺩ SECOND TERM 1433-1434 AH. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) I-THE EXTERNAL FEATURES OF INSECTS INTRODUCTION: Insects, from Latin: Insectum, translation of Greek: Entomon. Insects are the most diverse group of animals on the planet, and include more than half of all known living organisms. Insects may be found in nearly all environments. SCIENTIFIC CLASSIFICATION OF INSECTS: Kingdom: Animalia Phylum: Arthropoda Sub-phylum: Mandibulata Super-class: Hexapoda Class: Insecta (according to Linnaeus, 1758). The basic structure of an insect is best studied by the examination of a common type, for example: Grasshopper. The grasshopper is a large insect (up to 8 cm. in length). The body is narrow, elongated, cylindrical and bilaterally symmetrical. The usual body coloration is yellowish or brownish with various color spots. The body is covered with a hard chitinous cuticle and consists of a number of movable segments which separated by flexible membranes. Figure (1, a and b) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (1, a): Migratory Locust (dorsal view) Figure (1, b): The body regions of the American cockroach DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) A- THE INSECT'S BODY REGIONS The segmented body of the Grasshopper is divided into THREE regions: 1- HEAD 2- THORAX 3- ABDOMEN. 1- HEAD: The head is made up of six segment fused together (not visible in the adult, may be observed in the embryo). The head bears one pair of compound eyes, three simple ocelli, one pair of antennae, and chewing mouthparts. 2- THORAX: The segments of the thorax are THREE and known as - A large anterior prothorax. - A middle mesothorax. - A posterior metathorax. Each thoracic segment has a pair of jointed legs. All legs (in grasshopper "Locust") are used in walking and climbing, but only the metathoracic legs are specialized for jumping . In Locust, each of the mesothorax and metathorax bears a pair of wings. The two pairs of wings are different from each other. Figure (2) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (2): The thoracic segments of Locust Also, the mesothorax and metathorax bears two pairs of ventrolaterally openings of the respiratory system (spiracles). 3- ABDOMEN: The abdomen (in grasshopper) is slender and cylindrical, consisting of ELEVEN segments. Each segments has a dorsal tergum and ventral sternum, there being no pleura. Eight pairs of spiracles are present on the lower side of segment "1" to segment "9". Figure (3) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (3): Spiracles in the abdomen and thorax The tip of the abdomen contains structures by which the sexes can be distinguished (male or female). A- INSECT'S HEAD Head is made up of sex fused segments. The head parts are Frons, Gena, Post gena, Vertex, Occiput and Post occiput. 1- Types of head (position of the insect's head): a) Prognathous type: In which the long axis of the head is horizontal and in line with the long axis of the insects' body. The mouth parts are forwards. Ex.,: Most beetles, Figure (4). b) Hypognathous type: In which the long axis of the head is vertical. The mouth parts points downwards. Example: Grasshoppers, Figure (4). c) Opisthognathous type: In which the long axis of the head is horizontal and in line with the long axis of the insect's body. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) The mouthparts are found on the Venter and are directed downwards and backwards (between the legs). Example: Plant sucking bugs, Figure (4). Figure (4): Positions of the insect's head 2- Types of eyes: a) Simple ocelli: - Dorsal ocelli, Ex.,: Grasshoppers, Figure (5). - Lateral ocelli, Ex.,: Caterpillars of Lepidoptera, Figure (6). b) Compound eyes, Ex.,: House flies, Figure (7). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (5): Dorsal ocelli of Grasshopper Figure (6): Lateral ocelli of Caterpillars of Lepidoptera DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (7): Compound eyes of Housefly 3- Appendages of the insect's head: [Antennae and Mouthparts] a) The antenna: Definition: "These are a pair of segmented sensory organs located in front or between the eyes". c) Structure: Scape – Pedicel – Flagellum. Figure (8). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (8): Structure of antenna Function: "They carry hairs which may be of tactile, olfactory, gustatory or auditory organs". Types of antennae: Different types of antennae are shown in the Figures: (9, a, b, c, d, e, f, g, h, i and j). - Setaceous (bristle-like), Example: Cockroaches. -Filiform (thread-like), Example: Grasshoppers. -Moniliform (bed-like), Example: White ants. -Serrate (saw-like), Example: Click beetles. -Clavate (club-like), Example: Butterflies and Moths. -Capitate (modified clavate-like), Ex.,: Tribolum castaneum. -Lamellate (leaf-like), Example: Scarab beetles. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) -Flabellate (tongue-like), Example: Ceder beetles. -Pectinate (comb-like), Example: Female moth. -Bipectinate: Its segments bear lateral processes on both sides Example: Male moth of silk worm. -Plumose (feathery-like), Example: Male mosquitoes. -Pilose (like plumose but with short hairs), Example: Female mosquitoes. -Geniculate (elbow type): Ex.,: Honey bee. -Aristate type: The last segment enlarged and has a dorsal bristle (arista), Ex.,: housefly. -Stylate type: Most of its segments bear a style. Ex.,: Tabanids. -Flat type: Most of its segments are flat. Ex.,: Ome grasshoppers. Fig. (9, a): Setaceous antenna (bristle-like)- Ex.,: Cockroaches DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Fig. (9, b): Moniliform antenna (bed-like)- Ex.,: White ants Fig. (9, c): Serrate antenna (saw-like)- Ex.,: Click beetles Fig. (9, d): Clavate antenna (club-like)- Ex.,: Butterflies Fig. (9, e): Capitate (modified clavate-like), Ex.,: Tribolum castaneum Fig. (9, f): Lamellate (leaf-like), Ex.,: Scarab beetles DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Fig. (9, g): Plumose (feathery-like), Ex.,: Male mosquitoes Fig. (9, h):Geniculate (elbow type): Ex.,: Honey bee Fig. (9, i): Aristate type- Ex.,: Housefly DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Fig. (9, j): Stylate type- Ex.,: Tabanids b) The mouthparts: The mouthparts are greatly modified in different insect groups, and are used in classification and identification. Insect mouthparts typically consist of: - A labrum. - A pair of mandibles. - A pair of maxillae. - A labium. - A hypopharynx. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Types of mouthparts i- Biting or chewing type: This is the primitive kind, from which, all other types of mouthparts have evolved. These mouthparts are adapted for chewing up and swallowing the pieces of plants and animals. Ex.,: Periplaneta americana "Cockroach", Figure (10) and Grasshoppers, Figure (11). Figure (10): Chewing mouthparts of Cockroach DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (11): Chewing mouthparts of Locust ii- Chewing and lapping type: These mouthparts serve for both biting and licking. The mouthparts are adapted (modified) for collecting nectar, pollen of flowers and moulding the wax. Ex.,: Honey bee worker, Figure (12). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (12): Chewing and lapping mouthparts of Honey bee worker iii- Piercing sucking type: These mouthparts of many groups of insects are modified to pierce tissues and suck juices. These include two kinds: - Plant feeder insects: In which the insect mouthparts suck juices from plants, Ex.,: Aphids and Scale insects. - Blood sucking insects: In which the insect mouthparts suck blood from birds, mammals and man. Ex.,: Mosquitoes "Culex sp.", and "Anopheles sp." Figure (13); Fleas Figure (14) and Bed bugs, Figure (15). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (13): Piercing sucking mouthpart of Culex and Anopheles sp. Figure (14): Piercing sucking mouthpart of Fleas DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (15): Piercing sucking mouthpart of Bed bug B- INSECT'S THORAX 1- Structure of insect thorax: Thorax is the second body region of insects. It is composed of THREE segments named: *PROTHORAX (First thoracic segment). *MESOTHORAX (second thoracic segment). *METATHORAX (Third thoracic segment). Figure (16). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (16): The thoracic segments of Locust Each thoracic segment consists of: - A TERGUM "a dorsal plate". - A STERNUM "a ventral plate". - PLEURA "lateral plates". 2- Appendages of the insect's thorax: [Legs and Wings] a) Legs: Each leg is composed of coax, trochanter, femur, tibia and tarsus (with two claws and arolium). Figure (17) The function of the legs is primitively for walking or running. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (17): The general structure of walking leg of Cockroach Modification of legs:-WALKING OR RUNNING: Ex.,: Cockroaches, Figure (18). -WALKING ON SMOOTH SURFACES LEGS: Ex.,: House fly, Figure (19). -JUMPING LEGS: Ex.,: Hind leg of grasshoppers, Figure (20). -SEIZING LEGS "grasping": Ex.,: Fore legs of the preying mantid, Figure (21). -DIGGING LEGS "burrowing": Ex.,: Fore legs of the mole cricket, Figure (21). -SWIMMING LEGS: Ex.,: Hind legs of water beetles, Figure (21). -COLLECTING FOOD TYPE OF LEGS: Ex.,: Hind legs of the honey bee. Figure (22). -CLINGING LEGS: Ex.,: Human louse. Figure (23). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (18): Walking or running leg of Cockroach Figure (19): Walking on smooth surface leg of House fly Figure (20): Jumping leg of Locust DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (21): Some modifications of the insect's legs Figure (22): Collecting food type of leg (hind leg of honey bee worker) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (23): Clinging legs of Lice b) Wings: - The presence of wings is one of the most characteristic features of insects and their dominance may be attributed to the possession of these organs. - Wings are absent in Apterygota; while reduced in some orders of Pterygota (due to their degeneration). Definition of wings: Wings are considered to be a plate-like expansion of the body wall, where the two walls have become closely applied. Along certain lines however, the walls remain separated, thus giving rise to the framework of the wings plate "veins". DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Structure of wings: The wings are more or less triangular in shape, having: THREE margins (costal, apical and anal margin) and THREE angles (humeral, apical and anal angles). Types of wings: 1. LEATHERY TYPE (Tegmina), Example: Fore wings of Grasshoppers, Figure (24). 2. ELYTRA TYPE, Ex.,: Fore wings of beetles, Figure (25). 3. HEMI-ELYTRA, Ex.,: Fore wings of hemipterous insects, Figure (26). 4. HAIRY TYPE, Ex.,: Winged forms of Thrips, Figure (27). 5. LACE TYPE, Ex.,: Wings of adult neuropterous insects, Figure (28). 6. SCALY TYPE, Ex.,: Moth and Butterflies, Figure (29). 7. MEMBRANOUS TYPE, Example: Wings of order: Hymenoptera and hind wings of most insects, Figure (30). 8. HALTERS TYPE, Example: Hind wings of house flies, Figure (31). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (24): Tegmina fore wing of Locust Figure (25): Elytra fore wing of order Coleoptera Figure (26): Hemi-elytra fore wing of hemipterous insects DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (27): Hairy wing of Winged forms of Thrips Figure (28): lace wings of adult neuropterous insects Figure (29): Scaly wings of butterfly DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (30): Membranous wings of order Hymenoptera Figure (31): HALTERS TYPE (hind wings of O.: Diptera) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) C- INSECT'S ABDOMEN 1- Structure of the abdomen: Abdomen is the third part of insect's body, with clear segmentation. The abdominal segments are ELEVEN. The posterior abdominal segments are modified for mating and oviposition. Each segment is made up of a dorsal tergum and a ventral sternum only. There are EIGHT pairs of abdominal spiracles. 2- Abdominal appendage of adult insects: a) Visceral abdominal appendages: Ex.,: Collembola and Silver fish Figures (32, a & b). b) Genitalia: The genitalia in male insects is termed genital claspers, while in female, known the ovipositor. The external genitalia may be modified into: -Short ovipositor, Ex.,: Grasshopper, Figure (33). -Much elongated ovipositor, Ex.: Pimphla sp., Figure (34). -Sting ovipositor, Ex.,: Honey bee worker and Female wasps, Figures (35, a & b). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (32, a): Visceral abdominal appendages of Collembola Figure (32, b): Visceral abdominal appendages of Silver fish Figure (33): Short ovipositor of Locust, laying the eggs in sand DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (34): Much elongated ovipositor of Pimphla sp. Figure (35, a): Modified ovipositor into sting apparatus (worker of honey bee) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (35, b): Sting of honey bee worker c) Terminal Abdominal appendages: CERCI: The cerci may be segmented or unsegmented. i- Segmented cerci (short), Ex.,: Cockroach. ii- Unsegmented cerci, Ex.,: Grasshopper. iii- Unsegmented cerci (Forceps–like): which are used for grasping the prey and other defense functions, Ex.,: Dermaptera. STYLI: In male, the 9th sternum bears a pair of short styles, while absent in female cockroaches. d) Abdominal appendages of immature insect: i- Abdominal prolegs: The ten abdominal appendages bears FIVE pairs of prolegs (pseudo DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) legs), Ex.,: Caterpillar (Lepidopterous larvae). Figure (36). ii- Gills: There is a long tube (siphon) open to the outside by a pair of spiracle, as in Culex sp. larvae. The siphon is projecting above the surface of water to take air oxygen. Figure (37). Figure (36): Abdominal appendages of immature insect (caterpillar) DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (37): Larva of Culex sp. in (B) Showing the siphon DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) II- METAMORPHOSIS IN INSECTS The term "metamorphosis" is derived from TWO Greek words, meta: change; and morph: form [i.e.: a change in the form]. A- Definition of metamorphosis: "Metamorphosis is the transformation of an immature larval individual into a sexually mature adult of different form, structure and habit of life". NYMPHS: Generally resemble the adult, except lack of wings and genitalia, Example: Grasshoppers. LARVAE: Larvae are usually worm-like, with short legs, without wings and compound eyes, with chewing mouthparts and its diet varies from that of the adult, Ex.,: Larvae of Butter flies, House flies and Beetles. B- Types of metamorphosis: There are different degrees of metamorphosis, depending upon the external changes during development. 1- AMETABOLA (Without metamorphosis): The adult results from the larva which resemble the adult, except for its small size and the under developed genitalia, Ex.,: Collembola and Silver fish, Figure (37). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) i.e.: Egg → Small adult Figure (37): AMETABOLA in Silver fish 2- PAUROMETABOLA (Gradual metamorphosis): The growth of wings occurs gradually between successive moults, Ex.,: Grasshoppers, Figure (38). i.e.: Egg → series of Nymphs → Adult Figure (38): PAUROMETABOLA in Grasshoppers DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) 3- HEMIMETABOLA (Incomplete metamorphosis): In this case, the immature forms are aquatic, called "Naiads". They breathe by gills and have other aquatic habits. Whereas, the adults are terrestrial or aerial, and respire by trachea, Ex.,: Dragon flies, Figure (39). i.e.: Egg → series of Naiads → Adult Figure (39): HEMIMETABOLA in Dragon fly 4- HOLOMETABOLA (Complete metamorphosis): In this type of metamorphosis, the egg hatches to give a worm-like "larva", that feeds and moults (more than one), and enter the resting stage "pupa", which finally transformed into the adult, Example: House flies, Mosquitoes and Butter flies, Figure (40). DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) i.e.: Egg → Larva → Pupa → Adult Pupa is the resting stage between larva and adult, during which the larva surrounds itself in a secreted case "puparium", and transform into the adult. Figure (40): HOLOMETABOLA in Butter fly 5- HYPERMETABOLA: In this type, the eggs hatch to give larvae, which differ in habit and type of feed, then enter the pupal stage, which finally transformed into the adult, Example: Blister beetles, Figure (41). i.e.: Egg → different Larvae → Pupa → Adult DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) Figure (41): HYPERMETABOLA in Blister beetles DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) III- LARVAE AND PUPAE "Larvae of insects differ from adult insects in that, most of them have developed features which adapt them to their particular mode of life". A- TYPES OF INSECT'S LARVAE There are however, THREE main types of insect larvae, namely: Polypod, Oligopod, and Apodous. 1- POLYPOD LARVAE (eruciform): They have the following features: - Well-defined segmentation. - Abdominal limbs (prolegs) present. - Antenna and thoracic legs present (poorly developed). - It is poorly sclerotized with cylindrical body. - They are usually sluggish and live near their food. - Examples: Caterpillars of Lepidoptera. 2- OLIGOPOD LARVAE: They have the following features: - Well-developed thoracic limbs. - Abdominal limbs (prolegs) absent. - Pair of abdominal cerci (or caudal processes may be present). - Oligopod larvae may be distinguished into two types; campodeiform and scarabaeiform larvae. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) a) Campodeiform larvae: - Larvae have prognathous head, legs are long. There is usually a pair of terminal abdominal processes. Generally very active, usually predatory. - Examples: Aphid lions larvae (Neuroptera) – Cybister larvae (Coleoptera). b) Scarabaeiform larvae: They are characterized by the following: - Body is soft, cylindrical and C-shaped. - Thoracic legs are short. - No caudal process or appendages. - Most of them usually move slowly, and live in the ground or in decaying wood. - Example: Scarab beetle. 3- APODOUS LARVAE (vermiform): These are typical worm like larvae. They are characterized by the following features: - Thoracic and abdominal appendages are totally absent. - Poorly developed head. - Often blind. There are THREE forms of apodous larvae; according to the degree of sclerotization of the head. a) Euocephalous: - With will sclerotized head capsule. Example: Mosquito larva. DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) b) Hemicephalous: With a reduced head capsule. Example: Tabanus larva. c) Acephalous: Without a head capsule. Example: Musca larva. B- TYPES OF INSECT'S PUPAE The pupa is the resting stage in all holometabolous insects. The pupa is incapable of feeding and is quiescent. FOUR types of the insect pupae can be recognized. 1- EXARATE PUPAE: The appendages are not glued to the body, but are free. Example: Honey bee pupa, Figure (42). Figure (42): EXARATE PUPAE in Honey bee DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) 2- OBTECT PUPAE: The appendages are visible, but they are closely glued to the body. The pupa is covered with a tight-fitting transparent skin and only the posterior end of the abdomen is movable. Example: Cotton leaf worm pupa, Figure (43). Figure (43): OBTECT PUPAE of Cotton leaf worm 3- COARCTATE PUPAE: The appendages are not visible. The pupa is enclosed in a puparium (which is made from the last larval skin). Example: House fly pupa, Figure (44). Figure (44): COARCTATE PUPAE of House fly DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK PRACTICAL ENTOMOLOGY (BIO. 359) 4- ACTIVE PUPAE: The pupa of mosquitoes and of certain midges is active and is able to swim in water by the movements of the caudal end of the body. Example: Mosquito pupae, Figure (45). Figure (45): ACTIVE PUPAE of Mosquito DR./ IBRAHIM ABD EL-HAMID IBRAHIM RIZK