Category: Biology Second Paper

Juvenile hormone is secreted from the corpora alata gland in the nymph stage. It causes growth in the nymph stage.Dr. Siddiq Publications

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.

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.

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.

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.

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

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

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.

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.

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.