Guide to Aquatic Insects & Crustaceans

Crustaceans include crabs, barnacles, shrimp and lobsters.

The phylum Arthropoda includes both insects and crustaceans. Crustaceans such as crabs and shrimp are strictly aquatic, whereas insects may be found just about anywhere. Even so, aquatic environments such as rivers, streams and standing pools of water play a crucial role in the life cycle of certain insects as well.

Differences

There are several morphological differences between insects and crustaceans. Insects have six legs and three sections of the body. Crustaceans, on the other hand, have more than six limbs and only two body sections.

Life Cycles

Crustaceans are almost strictly aquatic creatures, though different varieties may live in saltwater versus freshwater environments. Insects, on the other hand, may require water for their larval stages but live on or above the water as adults.

Crustaceans on Land

There are a few examples of crustaceans that live on land. Such crustaceans are commonly confused with insects or other "bugs." The most widely known example of such a crustacean is the common pillbug.

Aquariums

Crustaceans such as shrimp can provide a critical service in an aquarium environment by cleaning up waste products, uneaten food or eating algae. However, they may also be tempting prey for fish. Likewise, certain larval stages of insects, such as mosquitoes, can serve as treats for fish such as the domestic betta.

References

• UMassAmherst: Some General Information About Aquatic Insects
• University of California Museum of Paleontology: Introduction of Arthropoda
• University of Nebraska: Marine Insect Homepage
• University of Kentucky Department of Entomology: Wee Beasties