Animals in the suborder Califera of the order Orthoptera are called phosphardians. Grasshoppers of the family Tettinonidae have long antennae and grasshoppers of the family Acrididae have short antennae. They are in solitary phase or gregrarius phase.
Habitat of grasshopper
Grasshoppers inhabit basically all types of habitats. Found everywhere including grasslands, pastures, fields, water bodies, bariforests, deserts. They are less abundant in places where the water rises and falls and the spawning grounds are submerged. They are migratory in adverse weather conditions. Moved from one area to another. Then it can go about 15 kilometers a day.
Food of grasshopper
Grasshoppers are herbivorous animals. Its main food is grass, leaves, grains etc. The nymph stage feeds on easily digestible grasses with tender branches. After shelling, the hard plant is eaten. They eat a variety of plants. Dr. Siddiq Publications
locust
Grasshoppers are diurnal and herbivorous insects. They live in tropical regions. Most of the time they run in groups. They gather in groups and eat the crops of the field. So they are called pests or locusts. Known locusts are – Schistocerca americana, Romalea microptera, Poekilocerus pictus etc.
Grasshopper found in Bangladesh
About 20,000 species of grasshoppers have been identified in the world. 20 species of grasshoppers have been found in Bangladesh.
1. Acrida exaltata
2. Aulacobothrus luteipes
3. Atractomorpha crenulata
4. Choroedocus robustus
5. Chondracris rosea
6. Cyrtacanthacris tatarica
7. Chrotogonus trachypterus
8. Eyprepocnemis rosea
9. Gastrimargus marmoratus
10. Gesonula punctifrons
11. Hieroglyphus banian
12. Oedaleus abruptus
13. Oxya fuscovittata
14. Phlaoba infumata
15. Poekilocerus pictus
16. Sphingonotus longipennis
17. Spathosternumprasiniferum
18. Trilophidia annulata
19. Xenocatantops humilis
Orthopterology
The branch of zoology which deals with Grasshoppers), Locust and Crickets is called Orthopterology.
Why are grasshoppers Insecta?
1. The body of grasshopper is chitinous and divided into head, thorax and abdomen
2. The thorax consists of a pair of jointed legs and a pair of wings
3. Has a branched tracheal system
4. Exhales through the air ducts
5. Free circulatory system exists
6. Excretion is accomplished by the Malpighian duct
External features of grasshopper
Grasshoppers are large in size. They are 8-9 cm in length. Their bodies are long, smooth and bilaterally symmetrical. The color of the body is mostly yellowish-green (yellowish) or brown. However, some species are bright blue-yellow (Poekilocerus pictus). Because of their striped spots on their bodies, they easily blend in with the environment and escape from the enemy. The body of the grasshopper consists of three parts. Head, thorax and abdomen.
1. Head: The head of the moth is pointed downwards at the front end, so it is called hypognathus. The head is pear-shaped. The exoskeleton of the skull is called the head capsule or epicranium. It consists of six sections. However, in intact animals there is no sign of segments and appears to be a single structure. and . The dorsal triangular region of the skull is called the vertex, the posterior leaf-like portion is called the occiput, the frontal region is the frons, the lateral region is the gena, and the lower rectangular leaf is the clypeus. The appendages of the head are mentioned:
(i) Antenna: There are two sensitive antennae on either side of the head in front of the base. It is cylindrical, cylindrical, unbranched and multi-lobed. Each antenna consists of three parts. Scape, pedicel and flagellum. The base of the antenna is the scape. Pedicel short and undivided. The flagellum is long and divided into 20-25 segments. Each segment contains sensory cells and neurons. Antennae sense touch, smell and sound waves. Dr. Siddiq Publications
(ii) Compound eye: On either side of the head there are two pistils (black, convex, large) like acorns and seeds. Each punjakshi consists of numerous polygonal chambers. Each of these is called an ommatidium. Grasshoppers have better vision than any other arthropod. They can identify colors with their eyes.
(iii) Ocelli: There are three ocelli or ocelli between the two capitals. Each ocellus is composed of a lens and a cluster of photosensitive cells. Each lens is thick, clear and made up of cuticles. Sensory cells contain pigments. It contains coniagen cells, retinular cells, rhabdomes, pigmented cells and neurons. Grasshoppers sense changes in light intensity with the ocellus. Many people think that a single reflection is formed through this. Dr. Siddiq Publications
(iv) Mouth parts: The movable jointed appendages around the mouth are called mouthparts. The mouthparts of grasshoppers are called mandibular mouthparts because they are used for chewing young leaves. It consists of five parts. Labrum, mandible, maxilla, labium and hypopharynx.
2. Thorax: The posterior part of the mandible is called thorax. It is divided into three parts. Anterior thorax or prothorax, middle thorax or mesothorax and posterior thorax or metathorax. Each segment is covered by a cuticle made of chitin. It is called sclerite. The thoracic sclerite consists of three segments. Targum, pleuron and sternum. Dr. Siddiq Publications
(i) Targum: Dorsal sclerite of thorax is called targum. The thoracic targa are called notum. The targum of prothorax is called pronotum, the targum of mesothorax is called mesonotum and the targum of metathorax is called metanotum. Pronotum large, broad and elongated. The dorsal tergum consists of four sclerites. Prescutum, scutum, scutellum and postscutellum.
(ii) Pleuron: The lateral sclerite of thorax is called pleuron. Each lateral pleuron consists of three sclerites. Episternum, epimeron and parateron.
(iii) Sternum: The thoracic sclerite is called sternum. Sternum with a single sclerite. Dr. Siddique Publications
The appendages of the thoracic region of the grasshopper are mentioned.
(i) Spiracle: There are two pairs of spiracles in the thoracic region. There is a pair of spiracles between the anterior and middle thorax and another pair between the middle and posterior thorax. Air enters the body through it. Dr. Siddiq Publications
(ii) Wings: Grasshoppers have two pairs of wings in the thoracic region. Medial thoracic or forewing and hind thoracic or hind wing. The front wings are short, narrow and stiff. They do not help to fly. These only cover the hind wings. Hence their elytra or wing cover or tegmina. The hind wings are large, broad, translucent and curtain-like. They help to fly. At rest the hind wings are folded. Each wing is composed of numerous small ducts and blood-filled veins. They are called nerves. Dr. Siddiq Publications
(iii) Legs: The thoracic region has three pairs of walking legs. Moths are called hexapoda because they have six legs on their body. Each leg has five segments. Coxa, trochanter, femur, tibia and tarsus. Coxa stout and triangular. Trochanter is small and triangular. The femur is long, cylindrical and strong. The femur is large and fleshy. The tarsus is divided into three smaller segments. These segments are called tarsomere. At the junction of the two tarsomeres there is a velvety cushion called the plantula. The last segment of the tarsus is called the pretarsus. The tip of the pretarsus has a pair of curved claws. Between the claws is a soft, hairy cushion called the palvulus. Their leg femurs are long and fleshy which is useful for jumping. This type of foot is called saltatory foot.
3. Abdomen: The last part of grasshopper’s body is called abdomen. It is long, narrow, soft and scaly. Its abdomen is made up of 11 segments. On the surface of the abdomen is the targum and on the phalanges is the sternum. But there are not so many pleurons. Its first fragment is incomplete. It contains only the targum. Abdominal organs are:
(i) Tympanum: The first abdominal segment contains the auditory sac or tympanum. There is an oval tympanic membrane surrounding the eardrum.
(ii) Spiracle: There are 8 pairs of spiracles in each segment from the first to the eighth segment of the abdomen. Air enters the body through it.
(iii) Anus and Genitals: The ninth segment of the male has the subgenital plate, the 10th segment has the anal sac and the 11th supra-anal plate and anus. But there is no anal style. The 11th abdominal segment contains the anus and the anal plate. Female grasshopper- ninth segment contains egg-laying organ ovipositor. The ovipositor is composed of 4 smooth lobes. Dr. Siddiq Publications
Mouth parts of grasshopper
The movable jointed appendages around the mouth are called mouthparts. The mouthparts of grasshoppers are called mandibular mouthparts because they are used for chewing young leaves. It consists of five parts. Labrum, mandible, maxilla, labium and hypopharynx.
1. Labrum: The round, wide, bilaterally symmetrical and flattened organ attached to the clypeus on the surface of the head is called the labrum. It is also called the upper lip. It is sensitive. It covers the mandible and helps in grasping food items.
2. Mandible: On either side of the mouth there is a pair of strong, short and triangular mandibles or jaws. Each mandible has several dark grooves on the inside. These grooves are called molar processes or denticles. Each mandible has two types of muscles. These are-
(i) Adductor muscle: The muscle on the inner side of the mandible is called adductor muscle. It contracts and pulls the mandible inwards.
(ii) Abductor muscle: The muscle on the outer side of the mandible is called the abductor muscle. It contracts and pulls the mandible outward. The work of the mandible is to bite and crush the food.
3. Maxilla: On either side of the mouth opening there is a pair of multi-segmented maxillae along the mandible. It consists of two main parts. Cardo and Stypes. The base of the maxilla is called the cardo. The long and slender upper part of the cardo is called the stipe. Gallia and lacinia are present at the head of the stipe. Besides, there is a five-segmented maxillary pulp on the outer side of the stipes. Maxillary pulp is sensitive. The function of the maxilla is to pick food, catch food, feed food into the mouth and clean the front legs.
4. Labium: A multi-jointed large compound appendage located below the mouth opening is called labium. It means understanding the quality of food, putting the food in the mouth and covering the mouth. The labium consists of two main parts. Submentum and Mentum.
(i) Submentum: The base of labium is called sub mentum. It is flat and wide. It connects the labium to the skull.
(ii) Mentum: The part between sub mentum and pre-mentum is called mentum. It is small and almost round. There are two labial pulps on the outside. Each labial palp is composed of three lobes. At the tip of the mentum is a ligula. The ligula has glossa on the inside and par glossa on the outside.
5. Hypopharynx: The long, soft and fleshy appendage between labrum and labium is called hypopharynx or lingya. Its base is folded and covered with cuticle. The subtongue is involved in moving food and swallowing food.
Digestive System of Grasshopper
The digestive system of grasshoppers consists of two parts. Alimentary canal and digestive gland. Dr. Siddiq Publications
Alimentary canal: The tube extending from mouth to anus is called alimentary canal. The alimentary canal of the grasshopper is divided into three parts. Stomodium, mesenteron and proctodeum.
1. Stomodium: The part from the stomata to the gizzard is called the anterior alimentary canal. It consists of six parts. These are:
(i) Mukhashidra: The openings in front of the alimentary canal are called mukhashidras. Food enters through it
(ii) Oral cavity: The part enclosed by the oral cavity after the oral cavity is called oral cavity. Food is mixed with saliva in the mouth. It takes the food from the mouth to the pharynx.
(iii) Pharynx: The small, muscular, narrow and cylindrical part located behind the mouth is called pharynx. Through this, food enters the esophagus.
(iv) Esophagus: The narrow, long and cylindrical part after pharynx is called esophagus. It is covered by a thin wall. It transports the food to the crop.
(v) Croup: Esophagus swells to form a sac-like croup. It is thin walled. Food is temporarily stored in it. Food digestion starts from here. Dr. Siddiq Publications
(vi) Gizzard or proventriculus: The posterior extension of the crop is called gizzard. It is a thick, muscular and triangular sac. Its wall is made up of tough, thick and circular muscles. The anterior part of the gizzard is called the armarium and the posterior part is the stomodium captica. Armarium wall folded longitudinally to form six leaf-like teeth. There is a pad-like layer behind the teeth. These leaves have fine bristles or hairs. Longitudinal folds contain bristles in deep pits. Gizzard teeth crush food. Bristle or Rome serves as strainer. Kapatika prevents reverse flow of food.
2. Middle alimentary canal or mesenteron: The part from gizzard to proctodeum is called mesenteron. The junction of the gizzard and the mesentery is called the cardia. The mesentery is called the stomach. The anterior and posterior ends of the stomach have muscular rings or sphincters. It is short and syntactic. It arises from the endoderm and is covered by the peritrophic membrane. The peritrophic membrane prevents food from sticking to the intestinal wall. It protects the intestines from damage. At the junction of the anterior and middle alimentary canal are 6 pairs of hepatic or gastric sica. Hepatic caeca are long, hollow and twisted. Stomach holds food and digests food. Hepatic cica helps in food absorption. Dr. Siddiq Publications
3. Proctodaeum: The posterior part of the middle esophagus is the posterior esophagus. There are 10–15 Malpighian ducts at the junction of the middle and posterior alimentary canals. The posterior alimentary canal consists of four parts. Ileum, colon, rectum and anus. Dr. Siddiq Publications
(i) Ileum: Ileum is narrow, short and tube like part. Its inner wall is furrowed and folded. These folds act like eyelids. Ileum digests food and absorbs nutrients.
(ii) Colon: The long irregular portion next to the ileum is called the colon. The diameter of the colon is greater than that of the ileum. It absorbs food.
(iii) Colon: The most posterior part of alimentary canal is called colon. It is swollen and thick-walled. Its inner wall has 6 folds. These folds are called rectal papillae. It absorbs excess water, mineral salts, amino acids etc. from stool. It also stores the undigested part of the food.
(iv) Anus: The opening at the end of the rectum is called the anus. It removes waste food from the body.
Digestive gland of grasshopper
Grasshoppers have two main digestive glands. Salivary Gland and Gastric Cica
1. Salivary Glands: A pair of compound leaf-like salivary glands are present on either side of the alimentary canal crop. Saliva is secreted from salivary glands. Saliva participates in food digestion.
2. Gastric sica: At the junction of gizzard and mesenteron there are 7-8 hepatic sica. Their inner mouth is open to the postural canal and the outer mouth is closed. Acid is secreted from the gastric sac. Nutritious foods aid in digestion. Dr. Siddiq Publications
Food Digestion System of Grasshopper
Grasshoppers eat green vegetables and foliage. Food is crushed by the mandible and maxilla. Then it is slippery mixed with lalars. Digestion of food by different parts of the alimentary canal is discussed below-
1. Digestion in crop: Food mixed with saliva is broken down into small particles due to contraction and expansion of the crop wall. Carbohydrates are converted into glucose by amylolytic (invertase, maltase, lactase) enzymes. Proteins are converted into amino acids under the influence of proteolytic (trypsin, protease, peptidase) enzymes. Lipolytic enzymes convert lipids into fatty acids and glycerol.
2. Digestion in the gizzard: As a result of the contraction and expansion of the gizzard, the food becomes very small particles.
3. Digestion in the Mesentery: Various enzymes are secreted from the hepatic caeca of the mid alimentary canal. All these enzymes digest food.
(i) Proteins are broken down into peptides under the action of trypsin enzyme. The peptide is then broken down into amino acids with the help of the enzyme eropsin.
(ii) Sugars are broken down into maltose under the action of amylase enzyme. Maltose is then broken down into glucose with the help of maltase enzyme.
(iii) Lipid is broken down into fatty acids and glycerol by the action of lipase enzyme.
Absorption of nutrients
The walls of the mesentery and hepatic ceca contain absorptive cells. These cells absorb most nutrients. Most of the glucose is absorbed in the hepatic cecum. The rectal wall absorbs excess water, minerals and amino acids from the stool. Grain-shaped feces are excreted in the anus. Dr. Siddiq Publications
Blood circulatory system of grasshopper
The system through which blood flows is called circulatory system. The circulatory system of grasshoppers is free-type (grasshoppers, grasshoppers, shrimps, mosquitoes, flies, spiders, snails, oysters, octopuses). The circulatory system in which blood is freed from the heart through the ostia or ducts into the body cavity or sinuses and returns to the heart through the ostia or ducts is called free circulatory system. It consists of four main parts. Hemolymph or blood, hemocele, dorsal vessels and accessory pulsating organs.
1. Hemolymph: Blood of grasshopper is made up of two components. Plasma and hemocytes.
(i) Plasma: Plasma is a colorless liquid. It does not contain hemoglobin. It contains protein, sugar, glycerol, amino acid, glucose, organic acid, ester, sterol, triglyceride, urea, uric acid, nitrogen, sodium, calcium, magnesium, potassium, phosphate, hemoxanthin, trihalose, diglyceride, tyrosine, trihalase etc. Dr. Siddiq Publications
(ii) Haemocytes or Blood Cells: Grasshopper blood contains only white blood cells or Haemocytes (15,000-60,000). It does not contain red blood cells. Haemocytes can be divided into three types. Prohemocyte, transitional hemocyte and giant hemocyte. Prohemocytes 6-9 mµ (23%), transitional hemocytes 9-19 mµ (68%) and giant hemocytes 19-23 mµ (9%).
Hemolymph function
(i) Haemolymph acts as a water reservoir. It contains 92% water.
(ii) It transports nutrients, minerals, hormonal secretions.
(iii) Maintains water balance in the body.
(iv) Wings help in circulation and shedding of shells.
(v) Hemocytes ingest microbes by the process of phagocytosis. As a result, disease is prevented.
(vi) Haemocytes help in blood clotting and wound healing.
(vii) Haemocytes secrete mucopolysaccharides to form connective tissue.
2. Haemocoel: The word haemocoel is formed from the Greek words haema meaning blood and coel meaning cavity. A body cavity filled with hemolymph is called a hemocele. Their hemocele is called myxocele. It is divided into three chambers or sinuses by the dorsal membrane and digital membrane. These are-
(i) Pericardial sinus: It is located above the dorsal membrane. It contains the heart.
(ii) Perivisceral sinus: It is located below the dorsal membrane. The alimentary canal is located in it. Dr. Siddiq Publications
(iii) Perineural sinuses: It is located under the digital membrane. It contains nerve fibers.
3. Dorsal canal: The dorsal canal consists of three parts. These are-
(i) Dorsal aorta: The first chamber of the heart narrows to form a cylindrical part. This is called the dorsal aorta. It extends from the forehead to the head. It does not contain ostia.
(ii) Heart or heart: The heart of the grasshopper is located in the pericardial sinus. It is composed of several funnel-shaped chambers. The first 3 chambers are located in the thorax and the last 10 chambers are located in the abdomen. In the region between the two chambers, the cardiac wall folds from both sides and enters the cardiac cavity. Each fold has a hole. It is called Ostia. Each chamber is connected to the pericardial sinus by ostia. A pore between two adjacent cells is called an intercellular pore.
(iii) Alary muscle: The triangular muscle that is attached to the heart is called Alary muscle. These muscles arise from the digital floor of the targum. Its broad end is attached to the heart. Alary muscles (6 pairs in total) contract and expand the heart.
4. Accessory Vibrating Organs: Antennae, legs and base of wings have accessory organs. Each appendage consists of an ampulla and a duct. They pulsate the hemolymph from the sinuses into the appendages.
Blood circulation system of grasshopper
Blood flows to different parts of the body as a result of the contraction and expansion of the heart and alary muscles of the grasshopper. Each chamber of the heart continuously contracts and expands like a wave to maintain normal blood flow. Blood circulation process is discussed.
Blood enters the pericardial sinuses from the perivisceral sinuses as a result of the contraction of the alary muscles. At this time, the chambers of the heart expand. As a result, blood from the pericardial sinus enters the cardiac cavity through the ostia. After filling with blood, the heart chambers contract. At this point the blood moves forward through the external ostia and enters the dorsal aorta. Blood enters the cerebral sinuses from the dorsal aorta. Blood then flows backward and enters the perivisceral sinuses and perineural sinuses. Blood circulates to different parts of the body through these two sinuses. At this time the blood enters the leg cavity from the perineural sinus and the wing from the pericardial sinus. Finally, the action of the alary muscles allows blood to flow from the perivisceral sinuses into the pericardial sinuses and repeat the cycle. Their heartbeat is 100-110 times per minute and it takes 30-60 minutes to circulate blood once in the body.
Excretory System
The system through which the nitrogenous waste products produced in metabolism are removed from the body is called the excretory system. The excretory organs of the grasshopper are Malpighian ducts, urate cells, uricose glands, nephrocytes, etc.
Main excretory organ Malpighian tube: Malpighian tube is the main excretory organ of grasshopper. Italian scientist Marcello Malpighi discovered this tube. It is named after him. It is a yellow tube. At the junction of the mesenteron and the proctodeum there are 6-8 bundles of ducts. Each cluster contains 12-15 Malpighian ducts. That is, its number is 60-150. Each tube is 25 mm in length and 0.10-1.00 mm in diameter. These tubules are of the nephridial type (connected at one end and free at the other end). It is hollow, cylindrical and unbranched. The hollow space inside the tube is called the lumen. The lumen is lined by epithelial cells. Epithelial cells have a basement membrane on the outside and cilia or microvilli on the inside. The cilia together form the brush border. Brush borders remove urea and urate from the blood. The outer wall of the duct has a foundation screen.
Malpighian duct function
1. Hemolymph collects nitrogenous wastes.
2. Passes waste material to the intestines.
3. Plays a role in osmoregulation.
Excretion system of grasshopper
Excretion is the process by which nitrogenous waste products produced by metabolism are removed from the body. The excretory process of grasshoppers is discussed below.
1. Malpighian tubule: Malpighian tubule absorbs water, potassium urate and CO2 from the blood. Inside the tubules, water, CO2 and potassium urate react together to produce potassium bicarbonate and uric acid. In these, potassium bicarbonate and water are reabsorbed and returned to the blood. Uric acid, on the other hand, passes into the rectum. Excess water from uric acid is absorbed in the colon and pure uric acid is excreted out of the body with stool.
2. Urate cells: The cells that store urea as urate are called urate cells. Urate cells mainly store protein, carbohydrates and fats as modified substances. In addition, it stores some uric acid in the hemolymph as urate. Dr. Siddiq Publications
3. Uricose Gland: The mushroom gland of male grass gharang contains uricos gland. They absorb excretory products from hemoceles and store them as uric acid. Uric acid is then excreted with the spermatozoa.
4. Cuticle: The nymph stage consists of amoebocyte cells floating in the hemocele. All these cells collect secretions from the blood and store them under the cuticle. During molting, the old cuticle along with the stored secretions are released.
Respiratory System of Grasshopper
The respiratory system of the grasshopper is called the tracheal system. The trachea or trachea and its branches join together to form a special type of respiratory system called tracheal system. Oxygen from the environment enters the body cells through the branches of the trachea and CO2 is released from the body cells in the same way. Different parts of the tracheal system are trachea, trachea and tracheole.
1. Spiracles: There are 10 pairs of spiracles in the pleura on both sides of the body. Of these, 2 pairs are located in the thoracic region and 8 pairs are located in the abdominal region. Each spiracle has a distinct ovoid pore. Spiracles are covered by peritrim. Pores are lined with hairy sieves. The bristled filter prevents the ingress of dust, germs and water.
2. Trachea or trachea: Trachea is the main respiratory organ of grasshopper. It is fine, elastic and branched. Trachea wall consists of three layers. outer epidermis, middle epithelial and inner intima. Inside the trachea the intima forms a spiral or ring-like ring. These rings are called tinidia. Trachea never goes silent because of tineaea. The main trachea are arranged longitudinally and transversely to form 3 pairs of tracheal cords. These are the dorsal longitudinal tracheal cord, the lateral longitudinal tracheal cord, and the lateral longitudinal tracheal cord. Air flows through the trachea to the entire body.
3. Tracheole: The trachea divides to form fine branches called tracheole. It is unicellular, without intima and tinidia and unbranched. Its diameter is 1 µm. It is filled with fluid. Oxygen and CO2 circulate in this liquid. Some branches of the trachea expand to form air sacs. Air is stored in the air sac. Dr. Siddiq Publications
Respiration System of Grasshopper
The trachea and tracheoles of grasshoppers are distributed in different parts of the body like a network and exchange gaseous substances. As their blood does not contain oxygen, it does not play any role in respiration. Inhales and exhales mainly through the trachea. Inhalation and exhalation processes are discussed.
1. Inspiration: Abdominal segments expand with muscle expansion. As a result, the volume of the inner cavity of the trachea increases. At this time the first four pairs of trachea open. Air containing oxygen from the environment enters the tracheal cavity through the trachea. Later oxygen from trachea reaches tracheole. Due to the thin wall of the tracheole, oxygen enters the body cells in the process of diffusion.
2. Expiration: CO2 is produced as a result of metabolism in body cells. The CO2 produced enters the tracheole in the process of diffusion. Then CO2 from the tracheole enters the trachea. During this time muscle contraction occurs. It compresses the trachea of the abdominal cavity and reduces the volume of the tracheal cavity. As a result, the remaining six airways are opened. CO2 present in the trachea is forcefully expelled through these spiracles.
Sensoryorgans of grasshoppers
Organs that receive various stimuli from the environment and generate appropriate reports through the nervous system are called sensory organs. The sensory organs of the grasshopper are:
1. Light Sensory Organs: The stem and ocellus of the grasshopper are the light sensory organs. An object’s reflection is formed in the constellation. Ocellus perceives the intensity of light.
2. Heat-Sensing Organs: Plantuli pads and roe are heat-sensing organs of grasshopper. Plantuli pads are located at the base of the first three tarsals of the foot. There is Rome in the antenna.
3. Auditory organs: The tympanic membrane and the hairs of the anal canal are the hearing organs of the grasshopper. The tympanic membrane lies on either side of the first ventricular septum.
4. Taste Organs: Maxillary pulp and hairs of labium are the taste organs of grasshopper. It selects suitable food.
5. Olfactory Organs: Some of the antennae’s hairs act as taste organs.
6. Touch Sensory Organs: Antennae, pulp, anal sac and leg hair are touch organs.
Sensory organs are transformed skin cells or sensilli. Each sensilla contains a sensory cell, a trichogen cell and a few tormogen cells. Sensilla are single in sense organs of taste, smell and touch. Sensilla are located in clusters in heat and sound sensory organs. Dr. Siddiq Publications
Ommatidium of grasshopper
Each hexagonal-shaped philospheric unit of the grasshopper’s stem is called an ommatidium. Each panicle contains 1200-1800 ommatidia. The structure of an ommatidium is described below.
1. Cornea: The colorless, transparent, convex and hexagonal covering on the outside of the ommatidium is called the cornea. It works like a lens.
2. Corneagen cells: A pair of corneal cells are present under the cornea. It creates the cornea. Dr. Siddiq Publications
3. Crystalline Corneal Cells: Below the corneal cells are four crystalline corneal cells. It forms crystalline cones.
4. Crystalline angle: Crystalline angle is a spheroid organ covered by crystalline angle cells. Light enters the ommatidium through this.
5. Irish Pigment Coat: The colored coating around the crystalline corner cells is called Irish pigment coat. It expands in intense light and covers the corner cells and shrinks in soft light and leaves the corner cells partially exposed.
6. Retinular cells: Below the angle cells there are 7 long retinular cells. It is decorated in circular form. One end of them is connected to the angle cell and the other end to the nerve fiber. It is a light sensor. Rhabdomes are formed from their secretion.
7. Rhabdome: The spindle-shaped cells in the center of the retinular cells are called rhabdome. Light is received through this. Dr. Siddiq Publications
8. Retinal sheath: The black membrane surrounding the retinal cells is called retinal sheath. It separates two adjacent ommatidia.
9. Basal membrane: The thin membrane on which the ommatidium rests is called the basal membrane. It contains the ommatidium.
Mechanism of reflection in grasshoppers
Reflexes are formed in the ommatidium of grasshoppers. Light enters the di-optical region of the ommatidium and reflections are formed in the retinal region. Apposition in bright light and superposition in dim light form reflections. Two processes are described below.Dr. Siddiq Publications
1. Apposition: In bright light each ommatidium can act independently. The iris and retinal sheaths of the ommatidium dilate in bright light. As a result, the crystalline angle is covered. Light rays from the object pass through the cornea directly into the rhabdome. In this case, light rays from the cornea of only one ommatidium reach the rhabdome. The rays of any neighboring ommatidium do not penetrate the rhabdome. A reflex is formed in an ommatidium. In this case the reflection looks like a mosaic floor stone. Hence it is called mosaic reflection.
2. Super position: In dim light, each ommatidium cannot function independently. The iris and retinal sheaths of the ommatidium shrink in dim light. As a result, the crystalline angle becomes uncovered. Light rays from the object enter the rhabdome through the cornea. In this case light rays from the cornea of one ommatidium in addition to light rays from neighboring ommatidiums enter the same rhabdome. As a result a blurred reflection is formed. This is called superposition reflection.
Reproductive System of Grasshopper
Grasshoppers are unisexual animals. They have male reproductive system and female reproductive system.
Male reproductive organs
1. Testes: It is the main organ of reproductive system. The testes are located in the 3rd, 4th and 5th segments of the body. Each sperm is made up of tiny follicles (30-40). Sperm are produced inside the follicle. Sperm are released through tubes called vasa efferentia.
2. Seminiferous ducts: Behind the scrotum are white, elastic and thread-like seminiferous tubules. It carries sperm. Dr. Siddiq Publications
3. Sperm: The terminal end of each vas deferens swells to form a sac-like structure. It is called Shukradhara. It stores sperm for a temporary period.
4. Ejaculatory duct: Two vas deferens join at the ninth segment to form the ejaculatory duct. Through this, the sperm enters the reproductive sac. Dr. Siddiq Publications
5. Genital Sac: Genital sac is a small cell in reproductive system. It houses the sperm.
6. Genital opening: The opening of the genital sac is called genital opening. Through this, the sperm is released outside the body. Dr. Siddiq Publications
7. Accessory Glands: The reproductive system consists of a pair of long tubular accessory glands. It opens into the excretory duct. The sperm is immersed in the fluid secreted from this gland and receives nutrients.
Reproduction process of grasshopper
The reproductive process of grasshoppers is discussed.
1. Mating: Grasshoppers mate in late summer. At this time, the male grasshopper injects the seminal fluid into the body of the female grasshopper. Seminal fluid contains sperm. Until the eggs are laid, the spermatozoa are deposited in the spermatheca of the female grasshopper. Dr. Siddiq Publications
2. Fertilization: The union of sperm and egg is called fertilization. After sexual intercourse, the sperm is stored in the female’s testicles. The fertilized egg and sperm meet inside the body of the female grasshopper. Dr. Siddiq Publications
3. Egg laying: A few days after mating, the female grasshopper lays eggs (centrolecithal). The female grasshopper digs a hole 10 cm deep with the ovipositor. They lay eggs in clusters of 10 in total. Each cluster contains 20 eggs. Eggs are 3–5 mm long and covered by vitelline membrane and chorion. The eggs are deposited in an egg-case and held in place by a cement-like substance.
4. Development: The process by which a full-fledged organism is formed from an embryo is called development. Fertilized grasshopper eggs take three weeks to hatch. Blooming stops in winter. This period is called diapause. Diapause protects the baby nymph from winter. First, micromeres and macromeres are formed by repeated divisions in the cleavage process. Micromeres and macromeres give rise to the blastula stage. Blastomere cells of blastula stage give rise to gastrula stage. From the gastrula stage, baby nymphs are formed step by step. The baby nymph transforms into an imago by molting. Later, full grasshoppers are born from the imago. Dr. Siddiq Publications
Metamorphosis of the grasshopper
The process by which the embryo transforms into a full-fledged organism through periodic changes is called metamorphosis. The metamorphosis of grasshoppers is incomplete or hemimetabolous. A metamorphosis in which the infant state of an animal bears partial resemblance to the adult state is called incomplete metamorphosis.
Metamorphosis of grasshopper
1. Nymph: A baby grasshopper emerges from the mature embryo. Baby grasshoppers are called nymphs. Nymphs are small in size, pale in body, wingless and have immature genitalia. Its body is covered by a coat of cuticle.
2. Imago: The nymph grows slowly. Under the influence of ecdysone hormone, its cuticle peels off. Molting is called moulting. Abandoned shells are called exuvium. The period between two moults is called stodium or instar. Their body consists of wing pads. Nymphs and wing pads grow larger after each moult. After changing the shell 11-12 times, the nymph turns into imago.
3. Full-grown Grasshopper: Imago is full-grown grasshopper. But the imago develops into a full-fledged organism through some accessory changes. Usually a full-fledged grasshopper is formed after 9 months by shedding the shell. Dr. Siddiq Publications
Metamorphosis hormone
Hormones that help animals to transform their bodies are called transformation hormones.
1. Prothoracicotropic hormone: Prothoracicotropic hormone is secreted from the intercerebral glands of the brain. It is also called brain hormone. It stimulates the prothoracic gland to secrete hormones.
2. Juvenile hormone: Juvenile hormone is secreted from the corpora alata gland in the nymph stage. It causes growth in the nymph stage.Dr. Siddiq Publications
3. Gonadotropic hormone: Gonadotropic hormone is secreted from the corpora allata gland in adults. It causes penis enlargement.
4. Ecdysone hormone: Ecdysone hormone is secreted from the prothoracic gland. It controls moulting. Dr. Siddiq Publications
5. Growth hormone: On both sides of the pharynx there are corpora cardiata glands. Growth hormone is secreted from this gland. Growth hormone causes the body to grow.
Neurogenic heart
A heart in which heartbeats are generated by ganglions or nerve glands is called a neurogenic heart. For example – grasshopper, cockroach, bee, moth etc.
Pheromones
Chemical substances secreted by the body of female moths that attract male moths to mate are called pheromones. It is also called sex pheromone. For example – grasshopper, cockroach, bee, moth etc. Other pheromones are alarm pheromones, territorial pheromones, trail pheromones, releaser pheromones, primer pheromones, scent pheromones etc.
Importance of grasshopper
1. Food chain: Grasshoppers are an important food in the grassland food chain. It is the favorite food of insects, spiders, reptiles, frogs, spiders, birds etc. in the food chain.
2. As human food: Grasshopper is one of the sources of protein. It is a favorite food of the people of South America, Africa, Japan, Vietnam, Philippines etc.
3. Nutrient cycle: Grasshopper’s excrement, shell and dead body mixed with the soil play an important role in the nutrient cycle of nature. Dr. Siddiq Publications
4. As a pest: Grasshoppers swarm and cut the young tips of crops. It damages crops. Dr. Siddiq Publications
5. Parasites: Some species of grasshoppers act as secondary hosts of roundworms and flatworms.
6. Garbage eating: Grasshopper eats environmental garbage and grass leaves.