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.

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.
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

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

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.

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.

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.

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.

Anatomy of Ommatidium : Structure of Ommatidium

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.

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