Download Ch. 10 Sec. 3 Notes Insects

Ch. 10 Sec. 3 Notes
Insects
*Moths, caterpillars, plant hoppers, dragonflies, cockroaches, and bees are all
insects.
Body Structure
*You can identify insects by counting their body sections and legs
*Insects are arthropods with 3 body sections, six legs, one pair of antennae, and
usually one or two pairs of wings.
*Three body sections are:
1. Head
-Most sense organs are located in head
Ex: Insects have 2 large compound eyes (Contain many lenses
to detect movement.) They also have simple eyes to distinguish
between light and darkness.
2. Thorax (midsection)
-Section where wings and legs are attached
-Insects are the only invertebrates that can fly
-Flying enables insects to find mates, food, new places to live, and
escape from predators
3. Abdomen
-Holds many of insects internal organs
-Small tubes are attached on the outside of the abdomen to allow
air for oxygen
Obtaining Food
*If it is living or once living, then an insect will eat it
Ex: plants, food, paper (in old books), animals, animal droppings
*An insect's mouthparts are adapted for a highly specific way of getting food
-Some insects have a sponge-like mouthpart that is used to lap up
decaying flesh
Ex: flies
-Some insects’ mouths' are shaped like a coil tube, which can uncoil and
be used like a drinking straw to suck up nectar from flowers
Ex: butterflies
-Some insects have sharp-edged mouthparts to cut through seeds, wood,
and other foods
Ex: ants
Life Cycle
*Insects begin life as tiny, hard-shelled, fertilized eggs
*After they hatch, insects go through metamorphosis that will produce them
into adult insects
Each insect species undergoes either complete metamorphosis or gradual
metamorphosis
Complete Metamorphosis
*4 different stages: egg, larva, pupa, and adult
-Egg hatches into larvae
-Larvae typically look similar to worms
-Larvae are specialized for eating and growing
-A larva becomes a pupa: insect is enclosed in a protective covering
-Insect is changing and developing inside pupa
-Insect releases from pupa as adult
Gradual Metamorphosis
*Has no distinct larval stage
*Egg hatches into a stage called a nymph
-Looks like the adult insect WITHOUT wings
*A nymph may molt several times before becoming an adult
Ex: Grasshoppers, cockroaches, dragonflies