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In 1984, the Hasbro Company took the toy world by storm when it
introduced the TRANSFORMERS, a group of mechanical toys designed to change from vehicles to robots and back again. These robots represented imaginary alien life forms that invaded earth and remained undetected by imitating cars and trucks. The idea of transforming from one life form to another sounds like wild science fiction to most people -- they have no idea that it happens every day right here on planet Earth. The real transformers are insects. These amazing creatures begin their lives in bodies (called larvae) that are specially designed for feeding and growing. The silkworm, for example, spends about 23 hours a day eating and increases its birth weight 86,000 times during the first 21 days of its life. When the feeding machine finishes growing, it becomes a pupa. All of the old body tissues are disassembled and rebuilt into a new life form, the adult. When the adult emerges from its pupal case, it is completely different from the larva in appearance and function. The adult is a reproductive machine, specially designed to attract a mate, produce eggs, and pass its timeless genetic heritage to the next generation of transformers.
The transformation process, known as metamorphosis, gives insects a unique survival advantage over most other living organisms. Adults may occupy a completely different habitat from the larvae; they may use a different food resource, or none at all. Metamorphosis allows them to escape from temporary habitats, like vernal ponds or deciduous leaves, before conditions become unfavorable for survival. Most insects have wings in their adult stage, and this gives them mobility to invade new habitats.
It's easy for teachers to demonstrate different types of development by rearing insects in a classroom.
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