By Taryn Tsujimoto March 23, 2014
- Know the similarities between a grasshopper and crayfish that may be phylum traits.
- Know the differences between a grasshopper and crayfish that may be class traits.
- Understand the internal and external anatomy of anthropods.
The Respiratory System
There are two different respiratory systems based on whether the arthropod is terrestrial or aquatic.
Terrestrial Arthropods: Oxygen enters the body through a spiracle (valve-like openings) where muscle contractions regulate the air flow, and the oxygen continues through the tracheal trunk then tracheal tubes which the diameter of the tubes get smaller to reach the entire body. Taenidia surrounds the inside of parts of the tracheal tube to keep the tube from collapsing, and the collapsible air sacs which lack taenidia store air.
Aquatic Arthropods: These arthropods have gills to allow oxygen pass through from water through diffusion. As the crayfish walks, the crayfish can breathe because the gills are located where the walking legs are attached.
- Athropods are separated into 4 groups: Chelicerates, Crustacea, Hexapods, and Myriapods.
- They have an exoskeleton.
- Have segmented bodies.
- There are 200 species of crayfish in North America.
- Grasshoppers have ears on their bellies.
A Hopping Discovery
The Caelifera, also known as the grasshopper, occupy grassy areas world wide dieting on the plant material surrounding them including grass, weeds, leaves, and shrubs. The grasshoppers are nutritious for reptiles, birds, small mammals, insects, and sometimes humans. However, it is tricky to catch these large insects. Grasshoppers have evolved to jump at amazing heights and distances. The strong legs project the large insect very far at a fast speed, the wings allow grasshoppers to migrate long distances during the cold season, and the brown, green color lets the grasshopper camouflage into the grass.
Hear Him Calling
Males attract females during late autumn and early winter by rubbing their hind legs against their wings to make a distinctive sound. The female will then lay her egg pods several inches below the ground where it sits until it hatches almost 9 months later. When the eggs hatch, the nymphs tunnel out to grow larger and die a few months after it reaches the adult stage.
The Mud Bug
Crayfish dwell in rivers looking like miniature lobsters with the yellow brown shell and similar body structure. Many species of fish, birds, and alligators feed on the crayfish,
humans will either cook and eat the crayfish or use it as bait, and the crayfish are nocturnal omnivores and scavengers that hunt worms, insects, dead fish, and insect larvae at night. The crayfish have developed two pincers called chellae to defend against predators, catch their prey, move around and pick up small things. The females have swimmerets under their abdomen to carry their eggs, when the eggs hatch, the babies stay with the mother until they are bigger.