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Woodlice

Crustacean Deduction

9-18-17 crustacean 049A5188Arthropods are invertebrates possessing an exoskeleton, a segmented body and paired jointed legs. Crustaceans make up one group of arthropods. Insects, spiders, ticks, mites, crabs, lobsters, woodlice, centipedes and millipedes are all crustaceans. Underneath a rotting log I recently discovered a crustacean resting right next to a clump of eggs. Not wanting to disturb the creature, I hazarded a guess as to its identity from what I could see. Its form narrowed it down to either a woodlouse (also known as sow bug, pill bug and roly-poly), centipede or millipede. Most centipedes have one pair of legs per body segment, eliminating them from the field of possibilities, for the photographed crustacean has two legs per body segment, as do millipedes and woodlice.

The next clue had to do with the eggs, which I presumed were produced by the creature right next to them. Woodlice have a “marsupium,” a chamber under the thorax which is filled with water in which their (often several hundred) eggs are brooded. Millipedes, on the other hand, lay from ten to three hundred eggs at a time, and deposit them on moist soil. In some species an adult remains to guard the eggs.

I cannot categorically say that today’s subject is a millipede and its eggs, but all signs point to it. If there is a crustacean expert among Naturally Curious readers, please confirm or correct my deduced identification!

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