What Kind of Bug Is This? Common Bug Groups

Is It a Pill Bug or Sow Bug? How to Tell Pill bugs , Sow bugs From Look-Alikes

Pill bugs / Sow bugs: 4 marks to check, what they are often confused with, whether they bite or sting, and where they turn up, quoted from university entomology and IPM sources.

These pages help you narrow a bug down to its group from what you can see. They are not medical advice. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.

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At a glance

Group: Class Crustacea, order Isopoda; not insects and not arachnids
Body plan: Body oblong to oval with an arched or half-domed back; adults have seven pairs of thin legs and two antennae; the body has seven larger thoracic segments and six smaller abdominal segments.
Size: Adults are about 1/3 to 3/4 inch long; juveniles are about 1/12 inch long.
Bites or stings: The source explicitly states these terrestrial isopods are harmless to humans.
Where you find them: Mostly hidden under organic litter or other debris on the ground, and beneath low-growing plant parts.

How to tell it is one of the pill bugs / sow bugs

When disturbed, pillbugs curl into a ball, while sowbugs cannot roll into a complete ball and typically scurry away instead.
Tail feature: pillbugs have a smooth, rounded rear end, while sowbugs have distinct appendages protruding from their rear.
One common name for the pillbug is "roly-poly" (also "woodlouse").
Neither an insect nor a true bug, but a crustacean in the order Isopoda.

Bites and stings

The source explicitly states these terrestrial isopods are harmless to humans. Seek medical care promptly for severe symptoms or any allergic reaction.

Pest or beneficial?

Overall important decomposers of organic matter (a beneficial role), but occasionally feed on seedlings, new roots, lower leaves, and fruit; in large numbers they can chew on fruit, succulent plant parts, seedlings, and vegetables that touch moist soil.

Where they turn up

Mostly hidden under organic litter or other debris on the ground, and beneath low-growing plant parts.

How to photograph it for identification

Get as close as your camera will focus, from directly above, in daylight or a bright lamp. Include the whole body with the legs and antennae in frame; a second shot from the side shows wings and body segments. Put a coin or ruler next to it for scale. For a bite or a bug found on skin or bedding, photograph the bug itself, not the mark. The app names the likely group; use the list above to confirm.

FAQ

Do pill bugs / sow bugs bite or sting?

The source explicitly states these terrestrial isopods are harmless to humans. Seek medical care promptly for severe symptoms or any sign of an allergic reaction.

What is the quickest way to recognize pill bugs / sow bugs?

When disturbed, pillbugs curl into a ball, while sowbugs cannot roll into a complete ball and typically scurry away instead.

Are pill bugs / sow bugs a pest?

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