Praying Mantid Eggcase

What is the difference between complete and incomplete metamorphosis in insects?

Incomplete and complete metamorphosis differ in the number of life cycle stages insects go through during their transformation from egg to adult. Complete metamorphosis has 4 life cycle stages and incomplete metamorphosis has 3 life cycle stages.

Complete Metamorphosis

Complete metamorphosis has four distinct life cycle stages: egg, larva, pupa and adult. Examples of insects that go through complete metamorphosis are butterflies, silkworms, mealworms and ladybugs. The larva can be worm-like, although you can still see the six legs. The larvae for moths and butterflies are called caterpillars. Maggots are the larval stage of flies. The larvae eat constantly and grow rapidly. A hard, protective case forms around the larva…this is the pupa stage. The pupa stage for a butterfly is called a chrysallis. The pupa stage for a moth is called a cocoon.

Incomplete Metamorphosis

Incomplete metamorphosis only has three life cycle stages: egg, nymph, adult. The nymph looks similar to, but a smaller version of, the adult. The nymph is also wingless. Examples of insects that go through incomplete metamorphosis are stinkbugs, earwigs, crickets, grasshoppers, cockroaches, ants and praying mantids.

A species of the earthworm can be found on every continent in the world. They burrow through soil and help keep it healthy. Some species of earthworm can grow over 13 feet long, all though most are a lot smaller than that. Earthworms have been dissected in science rooms throughout the world, although if dissection is not an option, you can use lifelike plastic figures to represent the earthworm lifecycle.

Earthworms have both organs needed for reproduction; the term used for this is hermaphrodite. When earthworms mate they lay next to each other and pass mucus like substance that allows each worms organs to be fertilized. After the earthworms mate they form eggs inside their bodies, then the worms separate and form cocoons which seal when they rolls off of the worm. The cocoon is buried underground and the hardened walls protect the forming worm.

The worms hatch as smaller earthworms that lack reproductive organs; this is the main difference between newly hatched worms and the fully developed. The worms start to develop reproductive organs after they are hatched. They are able to use their reproductive organs at around 12 months. Earthworms can sometimes live for more than 10 years depending on the species. In the United States earthworms range in color from red to brown, and in other countries they can be blue or green.

Check Out These Large Earthworms

Egg

Butterfly eggs consist of a hard outer shell; the outer shell has wax on the inside to prevent it from getting too dry. These eggs are usually affixed to a plant leaf with glue that quickly hardens. The egg stage lasts for a few weeks.

Caterpillar

During the larva stage the caterpillar consumes plant leaves, finding and consuming the plant leaves is how the caterpillar spends most of its time. Many caterpillars have markings on their rear end that look like eyes. This along with ability to produce chemicals that smell or are toxic offers defense from birds and other predators.

Pupa

This is the stage in which the caterpillar searches for a desirable location in which to turn itself from larva into a pupa. The caterpillar will attach itself to a branch or limb and moult for the last time. Metamorphosis takes place and a butterfly emerges at the end of this cycle.

Adult Butterfly

Adult Butterflies are not able to fly until their wings gain blood circulation and completely unfold; this usually takes 1-3 hours depending on the type of butterfly. Without a net or other type of protection they are very vulnerable while waiting for their wings to function.  The adult is known as the imago, as an adult the butterfly gains the ability to reproduce. The adult butterfly has 4 wings and 6 legs.

Learning Activity for Children

Butterflies are fascinating for children because of their beauty and the simple fact that they fly.  Rarely can a book teach a child the stages of a butterfly’s life cycle better than simply experiencing it.  Raising butterflies through their life cycle is a fun educational activity for children.  To successfully raise butterflies through their life cycle, you will need:

• Painted Lady Caterpillars with food.
• Vials and lids
• And a two foot hanging butterfly net

Heath Scientific provides these supplies along with complete instructions in a Live Butterfly Classroom Kit .  Though designed for the classroom, it is a great activity for parents and children of all ages.