Sow Bugs

Sow Bug Facts

• Appearance: flat and oval, built of overlapping plates, with 14 legs and two sets of antennae
• Size: up to about 1/2 inch
• Crustaceans, closer kin to crayfish and shrimp than to insects
• Eat rotting leaves, wood and other dead plant matter
• Hide under mulch and garden debris, and may wander into damp garages
• Can turn up in potted plant soil

Since they dry out fast, sow bugs keep to humid spots under stones, logs, boards and fallen leaves.

Sow Bug or Pillbug? How to Tell

Sow bugs and pillbugs are both land-dwelling crustaceans, and they are often found side by side. The difference is easy to check:

• Pillbugs have a rounded, domed back and roll into a tight ball when disturbed, which is why kids call them roly-polies.
• Sow bugs are flatter, cannot roll up completely, and have two small tail-like appendages sticking out from the rear.

Both are slate gray to brownish and up to about half an inch long. They are sometimes mistaken for millipedes, which have long, worm-like bodies with many more legs.

Biology: sow bugs breathe through gill-like structures on the underside, which is why they need moist surroundings and dry out quickly in low humidity. They molt in two halves, shedding the back half of the shell first and the front half a short time later, so you may spot one that looks two-toned. Females carry their eggs and newly hatched young in a fluid-filled pouch under the body.

Diet and activity: they mainly eat decaying leaves, wood and other organic matter, which helps break down mulch and compost. Occasionally they nibble seedlings or soft fruit resting on damp soil. They are mostly active at night and hide during the day.

In Florida: they are common in damp mulch, leaf litter and garden beds and can be active year-round. Learn what brings them indoors on the sow bug infestation page.