Members of the phylum Arthropoda include spiders, centipedes, insects, and crustaceans such as crabs. Arthropods have segmented bodies, jointed appendages, and cephalization. Arthropods exhibit different types of feeding specialization depending on their diets. Arthropods digest their food through extracellular digestion in a digestive tract.
Uca pugnax (Fiddler Crab) The Fiddler Crab, obtains its food by emerging from sand burrows during low tides to scoop up surface sand into its mouth parts. Its mouth parts contain fine hairs which sift through the sand; the organic material is then ingested by the Fiddler Crab. The Fiddler crab digests its food in a digestive tract where it is broken down and absorbed into the body. Its wastes leave through the anus.
Cryptocercus (Wood-Eating Cockroach) Wood-eating cockroaches obtain their food by eating wood. However, they are incapable of digesting the cellulose alone.To solve this problem, wood-eating cockroaches have symbiotic relationships with bacteria in their digestive tracts which digest the cellulose for them, allowing the host to extract the nutrients. Cryptocercus' wastes are removed from its anus.
Melanoplus differentialis ( Differential Grasshopper) Grasshoppers obtain their food by eating different plants and vegetation such as grasses and leaves. To assist their diet of vegetation, the mouth of a grasshopper contains a mandible and salivary glands. The digestive system of a grasshopper includes the mouth, the stomach and intestinal parts, and the anal region. Once the food is ground in the mouth, it enters the stomach where it is mixed with digestive enzymes and broken down. From the stomach, wastes which contain urea and uric acid enter the intestinal parts and anal region where they are then excreted.