In a normal human life cycle, you do not see a lot of change in our body structure. The only thing that changes is the size of our body. When we were born, we all had two legs, a pair of hands, a head, and a torso. After growing up, we still have the same number of body parts. But a baby insect will never look like the adult version of itself. But when it comes to insects, it is quite different. An insect's life cycle is nothing like a human life cycle. There are a lot of changes that occur in 4 stage life cycle insects. In an insect life cycle, the insect mostly undergoes through four different stages. The 4 stage life cycle insects are very common in nature. The four stages are eggs, larvae, pupa, and adult stage.
For example: Consider the life cycle of a butterfly. A butterfly is considered as one of the most beautiful 4 stage life cycle insects. All butterflies have complete metamorphosis. It first starts as an egg and then hatches into a caterpillar. After eating plenty, it turns into a pupa, which eventually turns into a butterfly.
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The image shows the life cycle of a butterfly.
The Egg Stage
The first stage of an insect life cycle is the egg stage. Almost all of the insects start their life as a fertilized egg. These eggs are tiny and come in a variety of colours, shapes, and sizes. You can easily find insect eggs on leaves, branches, and on the ground. Butterflies and moths like to lay their eggs on the bottom of the leaves. Some insects try to protect their eggs by applying a form like material over it.
The Larvae Stage
After two to three weeks, the eggs will hatch into larvae. Larvae are small worm looking insects. The larvae and the adult that it will become in the future will look completely different. Every species of larvae has a different way of hatching. For example, a flea larva will cut open the eggshell to hatch, while a caterpillar larva will eat its way out from the egg. As the larva keeps growing, it will continuously keep shedding its skin. This process of shedding the skin is called molting. When a larva hatches, it enters into the 1st instar stage. As soon as it sheds for the first time, it is said to enter the 2nd instar stage. The primary function of larvae is to eat nutrients abundant food and store them for the next stage. It is considered to be an eating machine, where it can eat more than its body weight. They eat, leaves, fruits, vegetables, crops, and suck on sap.
The Pupa Stage
Once the larva is done eating and storing food, it starts to enter the pupa stage. During this stage, the insect is mostly motionless, and it keeps resting until it is ready to transform into an adult insect. At this stage, the insect cannot feed on anything. The larvae always form a cocoon, to protect it from outside danger. The cocoon can be made up of different materials such as mud, silk, seeds, plant materials, or ground litter. The changes that happen inside the cocoon is called metamorphosis. Once the changes are complete, it will emerge out as an adult insect.
The Adult Stage
The adult stage is the last stage of the insect life cycle. Once the pupa is done transforming, and it has completed its metamorphosis, it emerges out of the cocoon as an adult insect. An adult insect will have legs, antennas, wings, hair, eyes, and a body. The primary function of an adult insect is to find a mate and reproduce the next generation of its species. The lifetime of some adult insects can only be a few days, and some male adults die as soon as they mate with female adult insects.
Nymphs fall under a particular category of insects. Nymphs only have three stages of the life cycle. There are eggs, nymphs, and adult insects. The eggs hatch directly into nymphs, and they continuously shed their skin or shell to form into adult insects. The nymph and the adult don't need to look the same. After each shedding they can change the shape and size of their body, slowly turning into an adult insect.
Q1. What is Entomology?
Ans. Entomo is a Greek word that means insects. Entomology is a field of science which deals with the study of insects. A person who dedicates their life in the field of entomology is called an entomologist. However, you don't need to be an entomologist to study the exciting and beautiful world of insects. Entomology is also the study of insect's nature in the wild. Here you get to look at the behaviour pattern, feeding pattern, genetics, adaptation, mating, hunting habits, and nomenclature of insects.
Q2. What is the Importance of Entomology?
Ans. Entomology has a significant contribution to the study of insect's relationship with the environment, organism, and humans. The study of insects can contribute a great deal to agriculture, biology, molecular science, forensics, animal health, and chemistry. It is also useful in the study of food production and storage, pharmaceutical epidemiology, chemical pest control, and biological diversity. By studying insects, we can get a lot of insights on diseases, and on how to store and protect our food source.