All Locust are grasshoppers, but not all grasshoppers are Locust. Locust is a handful of grasshoppers when they enter a swarming phase. A series of factors that vary by geographical area weather and species force grasshoppers to crowd each other. Their serotonin rises at that point and they begin to swarm, this kind of behavior is referred to as Gregariousness. This is called a rapid onset of social behavior. The mode of identifying the Locust from the grasshopper all comes down to how they behave. There are thousands of species of Locust in which at least 500 are known to cause crop damage and 50 are considered as major pests. Their reputation for destruction is very epic, you will not believe it until you see it happening. Locust swarms are of 3 types depending upon their population density they are as follows: outbreak, upsurge, and plague. Small pockets of swarms that are happening in a localized area are called an Outbreak. The large groups of such are called Upsurge, these are geographically confined. When large giant groups of Locust separated by different breeding locations all swarms together are called Plague. Gregariousness is usually caused when a Locust touches each other by their hind leg. As the population density increases typically due to shortage of food or a drought, typically this kind of contact physical contact increases as Locust comes together. This constant hind leg touching and tickling release a large number of neurotransmitters called Serotonin. This Serotonin is one of the happy hormones in humans which is typically released when we exercise and it regulates our moods. When the Locust is touching each other there is huge Serotonin buildup in their bodies in Locust whose hind legs are stimulated. Experiments have shown that this can occur in as few as 10 Locust if they are tightly packed. When these swarms they tend to adopt the aligned movement thereby flying or marching collectively. The flightless young once of the Locust are called Nymph, these are the once that march and they sprout wings they fly. Gregariousness also induces physiological changes, wherein the Locust change color as well becoming the typical yellow-brown color which we associate with Locust changing from the green grasshopper color. All of these changes are caused or induced by Serotonin. Large swarms of Locust can contain crores or billions of individuals. Locust can fly 200 km a day destroying all food crops and all kinds of greenery in their path. An adult Locust is capable of eating 2 kg of food a day, you can say it can eat its own body weight. Locust always breeds exponentially, where once a female can lay from 30 to 100 eggs. The flight or migration of the Locust is aided by the wind and they tend to move with the wind flow. Locust has been known throughout history, as they have even been recorded in biblical times. The oldest record dates back to Egypt to 2500 BCE depicted on Egyptian tombs.
The life cycle of a Locust has a few stages which are as follows.
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During this stage, the male locust finds a female locust of its species and inserts its semen into a sperm sac of the female which is found in the abdomen. In this process, the sperm is deposited in the female oviduct and this is stored in the sperm sac waiting for the eggs. The female of the locust species then releases the eggs which mix with the male Locust semen and get fertilized as they pass through the oviduct. A male and a female Locust are distinguished by the shape of the tip of the abdomen. In comparison, the female Locust is bigger to the male Locust on average.
Once the mating of the male and the female Locust is done, the female Locust finds a ground that is suitable for it to lay the eggs. The female makes a hole in the soil using their abdominal tip for it to lay the eggs by extending the membranes between the segments. The females then lay their eggs in the ground, this will be mostly in the warm damp soil or even in the sand. The female Locust lays the eggs in the groups of 50 which are deposited in the ground. These depositions where the eggs are laid in a shallow hole known as Pods, the deposition takes place 4 inches underground. The female Locust lays eggs somewhere around 50 to 100 eggs in a Pod at a time. Ther eggs are then later covered by foamy fluid, which hardens itself in order to protect the eggs acting as a protective barrier. The hatching of the eggs mainly depends upon the temperature and the moisture of the soil or sand. We can say it will take roughly 10 to 20 days for the eggs to hatch and the young once to come out.
Once the eggs are hatched the baby Locust comes out of the ground, by forcing their way to the surface. During this stage, they will not be having wings in them. They get around by hopping, that is how they get their name as hoppers. The duration in which they will be hopping is around 4 to 8 weeks, at this stage, they tend to gather in crowds. The baby Locust that comes out of the eggs is called Nymph or Hoppers. Post hatching them for over a period of 2 months the Nymph goes through 5 stages of molting called Instars. During each stage of the instars, the Nymph will shed their skin to allow for further development, this is done by pumping their body thereby trying to push their skin behind them. This is very hard work for them, but they seem to manage to perform it. This is done by attaching themselves firmly on a plant and very gently pushes itself further and further out of the old skin. When the Locust is completely out of the old body it hangs itself upside down for a while to rest. Later the soft body of the Locust begins to harden and the wings benign to open up. We can see the old skin of the Locust still hanging on the tree. Once they are out of their skin they start hopping. Post a few days they grow a little and their body becomes to harden and they become much darker in shade. As they continue to grow they shed their skin which is known as molting. Each time this happens they change color. At their initial stage, they will be having wing buds, which later grow fully as they reach adulthood. Over the completion of the 5th instar, we will see that the Locust wings will be fully developed at that time.
As the wings of the Locust are soft and not fully developed, Nymph’s wings are very tiny and they will not be able to fly. At this stage they usually walk, their long back legs help them make enormous keeps. If frightened they can jump up to 100 times the length of their body. These flightless Nymphs are called the Fledglings, this happens after the 5th molt. They spend most of their day eating, usually lying along the leaf hoping no one would spot them. They have an armor plating on them which gives them some protection. The wing wings will take about a week to harden, post these fledglings will be able to fly around with them reaching adulthood. During this stage of development, they have to consume a lot of vegetation in order to store the energy which will be later useful to them for reproduction and flight. They usually stay with large groups and spend most of their time eating. Having long legs helps them to climb upon the grasses. They can eat a whole crop until there is nothing very less time.
This is the final stage in the Locust life cycle, which involves a lot of movement and feeding. Locust at this stage will be having fully-fledged wings that are now fully developed and they will be capable of flying anywhere. It takes 2 weeks for fledglings to fully develop into an adult, we can say that now at this stage it is sexually mature. They tend to swarm together with the number somewhere around thousands, in the areas, especially where there are green feeds and they are very destructive in the garden areas. They usually travel in large swarms as they move from one feed to another after the exhaustion of the current feed. An adult Locust is said to have a lifespan of 8 to 10 weeks, during this period the male Locust mates with the female of the species to reproduce and die. They have their ears under the wings which look like holes there. Locust has tiny holes in the abdomen called the Spiracles, they breathe through them. The antenna on the head of the Locust is called Respules. The wings and the body have a lot more color during this phase still, there will be some changes that take place before the Locust is yellow in color.
1. What are the methods of control implemented for Locust?
Ans: The main method of control that has been implemented is by spreading the poisonous bait. The insecticides usually kill them by being eaten or by being in contact with their bodies. Only when the locality of these Locust is known can we use the poison bait. There should be a watch in widespread areas so that the swarms can be deducted before as soon as they emerge so that this information can then be shared with the anti-Locust departments. The other method which is employed is the use of insecticides which is spared over swarms of hoppers with the use of motor vehicles or anticrafts. We can also spray the vegetation which comes in the path of the hoppers. If we are able to identify the region where these have laid their eggs, insecticides in that particular surrounding area can be sprayed so that these are killed in the first attempt to destroy the crop. There are dangers in using such insecticides, although they would kill the Locust these chemicals are even dangerous to humans and the animals as well especially when used in the food crop. The 2 species of Locust the migrating and the red Locust are kept in check for a longer duration of time by implying better and effective control measures. There is another species of Locust called the desert Locust which poses a major threat. The government is trying its best to control this mess; they are even trying to manufacture safer insecticides. Even with all the measures we still see a Locust attack and the farmers are the ones that suffer the most as they experience misery and starvation.
2. What characters differentiate a grasshopper from Locust?
Ans: Both the grasshopper and the Locust are short-horned insects called Acrididae, they belong to a family called the Acrididae. This family also includes crickets and even the long-horned grasshoppers. Locust changes its behavior and appearance pertaining to the environmental conditions, unlike the grasshoppers. A Locust particularly changes it’s behavior when they are packed in high densities. Locusts become crowded when their behavior, morphology, appearance, physiology, habits, and ecology change very rapidly, this sudden change is called the phase change. When it comes to nature the grasshoppers are solitary, but the Locust are both solitary and very much depend on the changes in their environment. When the environmental condition is good and we see green vegetation around this usually promotes breeding for Locust they are very mobile and in groups, with large numbers, they turn into swarms, this is known as the gregarious phase. The outer layer of the Locust is covered with a special kind of skin called the cuticle. Although Locust and the grasshopper appearance is the same as the locust when the population density is low Locust behave as individuals much like grasshoppers. When coming to identifying Locust vs grasshoppers scientists say it comes down to how they behave. The Locust wings are longer and stronger which aid them in covering long distances whereas the wings in the grasshoppers are thin and tough at the front and whereas the outer wings will be flexible and wide.