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Complete Metamorphosis

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  • Complete metamorphosis: a change in body form with four stages: egg, larva, pupa, and adult.
  • Exoskeleton: hard body covering... more
  • Instar: stages in the growth of a larva.
  • Larva: the second, "worm-like" stage in the life cycle of insects that undergo complete metamorphosis (like caterpillars).
  • Pupa: resting stage during which tissues are reorganized from larval form to adult form. The pupa is the third body form in the life cycle of insects that undergo complete metamorphosis (like caterpillars).

Bee metamorphosisComplete metamorphosis has four stages: Egg, Larva, Pupa, and Adult

Complete metamorphosis begins with the insect hatching from an egg into a soft worm-like shape called a larva. Larvae have a very big appetite and can eat several times their own body weight every day. If humans did the same thing, babies would start out eating as much as 10 pounds of food each day. For insects, this super-sized larva diet makes them grow very fast and can change their color. 

Some larvae add more body segments as they grow. Scientists refer to these developmental changes as instars which are similar to how humans call their children babies, toddlers or teenagers. For example, instead of being called a baby, a very young larva would be called an instar 1 and a teenager would be called an instar 3. The number of instar stages can be different depending on the type of insect.

At the end of the larval stage the insect will make a hard shell where it will live and begin the pupa stage. At this stage the larva will stop eating and moving. The pupa appears lifeless, but one of Nature’s most amazing transformations is happening. Inside the pupa, the larva’s body will completely change into a fully grown adult.  Once the adult larva leaves the pupa it slowly stretches out and relaxes under the sun for a couple of hours while its exoskeleton dries out and hardens.

Insects with complete metamorphosis include beetles, bees, ants, butterflies, moths, fleas and mosquitoes.

ant metamorphosis

mosquito larva

Mosquito spend part of their lives as wingless larva living in pools of water.


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