Isopods (Armadillidium vulgare) are among the most morphologically diverse groups of crustaceans coming in varying sizes and shapes with approximately ten thousand known species. The habitats that an isopod lives in includes fresh water, salt water and on land. Some of the isopods in North America were introduced from Europe, their is one aquatic isopod that is native to North America. The pill bug also known as the wood louse or sow bug is one of the most familiar isopods that is often believed to be an insect. Most isopods live in the ocean.
Spiny, large isopods live in the deeper areas of the sea while some are parasites that make there home on fish, while others live in shelf and coastal waters as they move on plants and the floor of the sea.
Isopods all share some common characteristics. There are two pairs of antennae on the compound head, and a compound eye. A pair of maxillae, a pair of maxillipeds and a mandible make up the mouth of the isopod.The body of the isopod is made up of seven peronites that have seven similar pairs of legs, there isn’t a claw present on the first leg. A short potion of the abdominal regions is made up of six ploenites and a fusion of the telson to the last pleonite. The isopods all have one pair of non-jointed uropods and will molt the posterior before the anterior.
The isopods that live in the ocean breathe with gas exchange by the use of pleopods. Air sacs known as pseudotrachea which do not require submersion are incorporated in the pleopods of the isopods found on land.
The life span of the Isopod is only a few years. Molting of the female is when reproduction occurs, males will either carry or guard her until she molts. The genital duct is used to transfer sperm to the female from the male. The eggs that have been fertilized are released into the brood chamber known as the marsupium to be protected until they can be released. Internal brooding is done by some isopod species. The isopods are always released as juveniles that can be told apart from the adults by the fact they have only six segments to the body and are smaller.
The feeding habits of isopods vary with some being predators, some opportunistic and others being parasites. The parasites attach themselves to varies parts of fish or plants, predators actively hunt using the mouth and anterior legs to catch prey. Opportunistic isopods will scavenge and feed on dead animals. A bacteria that lives in the gut of the isopod allows it to digest leaves. Damage can be done to plants when they feed on them.
Environmental changes are something the isopod is sensitive to. They can sense changes in industrial waste and carbon dioxide which has lead to scientists using them to indicate changes in the ecosystem. They can be found in homes because they prefer moist places but do not do damage to the occupants possessions.
Sources:
http://www.dnr.sc.gov/marine/sertc/Isopod%20Crustaceans.pdf
http://cgi.unk.edu/hoback/ESCAPE/isopod_facts.html
