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SEM image of the week: Pill bug

Posted on Monday, June 11, 2012 by for SEM.

Armadillidiidae, better known as pill bugs, or roly polies, are crustaceans in the order isopoda. Armadillidiidae have the ability to roll into a ball as a defense mechanism; this ability is called conglobation. The pill bug is the only crustacean that can actually spend its entire life on land. Most pill bugs live for up to two years. Pill bugs mostly eat rotting vegetables and thrive best in a moist environment. They can be found under damp objects or in organic garbage. If they enter a dry place, such as a building, they will often dry out and die. Pill bugs form an important component of the larger decomposer animals in that same area, along with earthworms, and snails. They return organic matter to the soil where it’s further digested by fungi, bacteria, and protozoans making phosphates, nitrates, and other essential nutrients available to plants. Some people regard pill bugs as pests, but they barely do any damage to live vegetation (although they may feed on roots). Pill bugs are also important in places such as coal spoils and slag heaps where they remove toxic metal ions from the soil. They can take in metals such as copper, zinc, lead, and cadmium and crystallize them in their midguts.

A face only a mother could love. Do these remind you of crab legs? Pill bugs are the purely terrestrial cousins of crabs. The armor plates on the back are reminiscent of armadillos — thus the family name armadillidiidae.
The front "grill". Close up of an eye. Patterned "skin" to the side of the eye.

Image: Jasline Garcia and Evelyn Veliz. Text credit: Jasline Garcia. Caption credit: Glenn Elert.