Insect Information

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Mouth Parts

Chewing (beetles), Sucking (adult butterflies), Piercing (true bugs), Lapping (fly), None (some adult moths)

Life Cycles (Meatmorphosis):

1. Complete Metamorphosis (holometabolous). Larvae and adults of these insects are very different and a distinct pupae is formed. Some insects with complete metamorphosis are: beetles, flies, bees, lacewings, butterflies, ants, and caddis flies.

2. Incomplete (or simple) Metamorphosis (hemimetabolous). In these insects, the nymph more or less resembles the adult and there is no pupal stage. The example shown below is a plant bug. Some other insects with incomplete metamorphosis are: crickets, true bugs, termites, grasshoppers, and cockroaches.

3. Ametabolous insects show no metamorphosis. Here the adult looks like the immature except for the presence of genetalia and gonads. The silverfish is an example.

The exoskeleton limits the potential size of insects, but provides valuable protection to all parts of the insect including its eyes, antennae and the internal breathing tubes (tracheae). Once an insect becomes an adult it will not grow. To grow and become an adult, young insects shed or molt their exoskeleton. Molting happens several times before an insect becomes an adult. A new, flexible skeleton forms beneath the old, hard exoskeleton. While taking in extra air, the insect expands itself and splits the old skin. After crawling out of the old skin, the new, soft exoskeleton starts to harden in minutes but may take several hours or days to harden completely. For some insects like a butterfly, the caterpillar is very different from the adult butterfly. In other insects like grasshoppers the young insects resemble the adults. The younger stages, called nymphs may have different color patterns and undeveloped wings and sexual organs compared with the adult. Compare the pictures above to see the difference between these two kinds of metamorphosis.

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Center for Insect Science Education Outreach The University of Arizona
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