Isopoda: slaters

Characteristics
Isopods vary greatly in appearance and are common inhabitants of many environments. Slaters belong to the very large phylum of Crustacea of which most are marine dwellers and includes such groups as amphipods, beach hoppers, shrimp, crabs, lobsters, crayfish as well as isopods. Slaters are one of two groups of Crustacea that have become terrestrial. Slaters are the most conspicuous and are easily recognised by their heavily armoured, flattened bodies. Most species are grey in colour although some may have a pink hue. Slaters may range in size but are usually less than 15 millimetres in length. Their characteristics include:

Isopod species (slaters)

• 1 pair of prominent antennae and 1 pair of inconspicuous antennae

• 7 pairs of legs

• Simple or compound eyes composed of either single ocellus or many closely associated ocelli respectively

• Obvious uropods

Life Cycle
In slaters the male transfers a sperm packet to the female using his modified seventh legs. The eggs, of which there may be up to 100 or more are laid into a brood pouch which is a chamber formed by cuticle outgrowths at the base of the legs. Upon emerging from the brood pouch the young resemble adults but have only 6 body segments and 6 pairs of legs. They will gain their last segment and seventh pair of legs at later moults. Slaters moult in two separate stages, with the first half of the body shed, then a couple of days later the second half is shed.

Feeding
Slaters are omnivores or scavengers and feed upon decaying vegetable matter and associated fungi and also on animal matter. They form an important link in the food chain by recycling dead and decaying matter.

Habitat
Slaters mostly inhabit moist areas and are commonly found under rocks and logs, in leaf litter in forested areas and in the garden. Some species are found in the semiarid regions of inland Australia and several introduced species are common inhabitants of suburban areas commonly living in compost heaps and other moist situations.