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1. The Arthropod Phylum
Arthropod (arthro = jointed / pod = foot)
Characteristics of arthropods include:
Segmented bodies
No backbone
Bi-lateral symmetry
Exoskeleton
And you guessed it…. jointed legs!
2. Major Groups of Arthropods
Class Arachnida
Includes scorpions, spiders and mites
Two distinct body divisions
4 pairs of legs
First pair of appendages are chelicerae
Subphylum Mandibulata
Includes crustaceans, millipedes, and centipedes
The jaw limbs are mandibles
Class Insecta
- Body in three parts
- Three pairs of legs
- One pair of antennae
- Usually two pairs of wings
3. Insect External Anatomy
3 body regions
Head: Sensory Center
Thorax: Locomotory Center
Abdomen: Reproductive Center
4. Insect External Anatomy - Head
Antennae (1 pair)
Compound Eyes (1 pair)
Simple Eyes or Ocelli (3 total)
Mouthparts (paired mandibles, maxillae and labium)
Mouthparts (paired mandibles, maxillae and labium)
md = mandibles
lr = labrum
mx = maxillae
Lb = labium
- CHEWING: BEETLE Notice the sharp jaws (mandibles) of this predatory insect. Grasshoppers, wasps, beetles and ants are examples of insects with chewing mouthparts similar to people. They grasp food instrong jaws. The jaws move sideways like hand shears or pliers to cut, tear, andchew food. Animal-eaters may also have spines on their jaws or front legs.
- PIERCING-SUCKING: STINKBUG Insects that must pierce tissue to get to the fluids (blood in animals; sap in plants) need to have ‘sucking tubes’ that can pierce. The mosquito’s mouth looks like a long, piercing, sucking tube. Stylets in it move up and down into the victim
- SPONGING: HOUSEFLY This housefly uses a sponging technique. In the modified lip (labium), saliva secretions are pumped onto the food source. This wets and partially liquefies the food so it can be sponged up into the mouth.
- SIPHONING: BUTTERFLY A butterfly has a long proboscis (tube), which uncoils to suck up nectar from a flower.
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