Grasshopper Life Cycle

Introduction

Grasshoppers belong to the class Insecta of the phylum Arthropoda and are placed under the suborder Caelifera and order Orthoptera. They are flying insects and are more closely related to crickets. Grasshoppers are around 11,000 species widely distributed around the globe. They inhabit almost all parts of the earth where vegetation is present except the polar regions. They are common crop pests and are a severe problem for farmers. They feed on grasses and plants forming the first consumers of food chains. Animals like frogs and snakes eat grasshoppers forming the next trophic levels.

Characteristics

Grasshoppers are green, ochre brown or grey coloured. The adults are about 7cm in length with powerful hind legs that allow them to fly and leap. The body is divided into the head, thorax and abdomen. The head has thread-like antennae, eyes and powerful chewing mouthparts. Grasshoppers have a high camouflaging ability. Orthopteran insects are hemimetabolous insects with incomplete metamorphosis.

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Although they adopt a herbivorous mode of nutrition, sometimes they are omnivorous and feed on animal tissues and faeces.

Mating season

Grasshoppers mate as the autumn advances from summer to produce large populations of progeny ready for the next summer. During mating the male grasshopper deposits sperms on the abdomen of a female adult. Sperms travel to the eggs through a micropyle canal to carry over the fertilisation. And finally, the female lays eggs.

Life cycle

The grasshopper life cycle begins with the egg stage as the female lays eggs and advances into a nymph that finally develops into an adult.

Egg stage

After a successful mating followed by fertilisation, the female lays a cluster of eggs by pushing its abdomen into a soft substratum like loose earth or leaf litter. Eggs are rice grain shaped and are around 10-300 lying together as egg pods. The sticky substance sprayed by the female adult keeps all the eggs together as a pod.

The eggs remain in the dormant stage until the next warm season arrives that is till early summer or spring which is around 10 months far. During the next warm season, the nymphs emerge from hatched eggs.

Nymph

Nymphs physically resemble adults but they lack reproductive organs, and wings and have light-coloured bodies. The young nymphs start to feed on juicy and succulent plants. The nymph stage advances into adulthood through a series of 5 to 6 moulting stages. Through moulting, the nymph develops wing pads on the thorax and also grows its body size.

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Adult

Adults are relatively more efficient in mobility because of developed wings than nymphs. Although they are highly camouflaging, adults are great prey for small animals like birds, frogs, toads, lizards and snakes. They only have 50% survival chances. The adult grasshoppers have powerful chewing parts that allow them to voraciously feed on grasses and juicy plants. The head has large eyes and thread-like antennas. The presence of a pair of wings and powerful hind legs allow the flying and leaping making them highly mobile insects. The locomotory organs are also a survival strategy against their predators. Female grasshoppers are larger than males. Male wings have special structures that they rub together or over their hind legs to produce a special noise.

Locusts and grasshoppers

Locust and grasshoppers are confused to be two different types of organisms. But locusts are not a separate species and they are grasshoppers that adopted a social and gregarious behaviour. Under a set of environmental conditions when the population of grasshoppers is quite large, they adopt a social life and live as large swarms of locusts. Sometimes dry environments like drought followed by thick vegetation in limited areas drive a reproductive burst in grasshoppers that live in large populations as swarms.

Although both are morphologically similar, grasshoppers are flying insects in a specified environment and have simple wings. Locusts are adapted to fly long distances and have long and strong wings. Comparably, locusts have smaller sized bodies than grasshoppers. Most commonly locusts are short-horned grasshoppers.

Grasshoppers live a solitary life and pair up only during mating. Locusts live and travel in large groups for long distances and feed on any green vegetation they encounter during their travel. They cause severe crop damage and are farmers' enemies for being agricultural pests.

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Conclusion

Grasshoppers are flying arthropods. They are herbivorous insects sometimes adapting to the omnivorous mode of feeding. Grasshoppers are hemimetabolous insects with three stages of the life cycle. Adult grasshoppers are reproductively functional and mate as the autumn starts from summer and female adults lay eggs that hatch into nymphs. Nymphs lack reproductive organs and develop into adults after successive moultings. The adult grasshoppers live in a solitary mode of life while some environmental conditions like dense vegetation followed by drought can induce reproductive burst. Large swarms of grasshoppers adopt a gregarious behaviour and live in organised groups called locusts. Locusts are a threat to the crop plants and are farmers' enemies.

FAQs

Q1. Do grasshoppers have antennae?

Ans. Grasshoppers have two filiform (also called thread-like) antennae (also called horns) for sensing the stimuli from their surroundings. Some species have antennae with a narrow base and a wider end, while some have antennae with wider bases that taper as narrow ends. Grasshoppers are two types based on the antennae length. Long-horned grasshoppers and short-horned grasshoppers. Many locusts are short-horned grasshoppers.

Q2. How many eyes do grasshoppers have?

Ans. Grasshoppers have two large compound eyes and three simple eyes. Compound eyes lie at the base of antennae while the simple eyes are called ocelli.

Q3. What is the exoskeleton in grasshoppers?

Ans. The presence of a hard exoskeleton is a characteristic feature of most insects. Grasshoppers have a hard chitinous exoskeleton to protect the internal body parts and prevent water loss from the body.

Q4. What is moulting?

Ans. Moulting is also called ecdysis where an organism loses off or sheds off the outer skin or exoskeleton or feathers while a new layer forms. Insects, birds, and snakes exhibit the moulting process. Insects undergo moulting and which is a period of growth and is controlled by the hormone ecdysone. The new exoskeleton formed is quite soft during the initial stages and it gradually hardens over a period of time. Grasshopper nymphs undergo 5–6 moultings to develop into complete adults.

Q5. Are locusts an outcome of climate change?

Ans. Locust outbreaks are linked to climate changes. Sudden storms and frequent cyclones with heavy rainfalls in the arid regions provide the wet soils favourable for laying eggs. The vegetation is dependent on rain and provides nutrition for the population. Sudden storms out of the monsoons are a result of global warming. Lack of proper vegetation in arid areas drives the locust migration in search of fertile grasslands that can pose a severe risk to the croplands.