Roly-Poly Infestation Myth Vs. Fact: Are They Harmless or Household Pests?

Are roly-Poly Infestation Myth Vs. Fact: Are They Harmless or Household Pests a question on your mind? Read key explanations in our feature story.

Pillbugs belong to the family Armadillidiidae, classified under the suborder Oniscidea. Despite their everyday designation as bugs, they are not insects. They are terrestrial isopods, cousins of crabs, lobsters, and shrimp that migrated from prehistoric marine beds to dry land millions of years ago.

This lineage explains their unusual physiology. Instead of spiracles and tracheae, pillbugs breathe through specialized branchial appendages called pleopodal lungs, effectively functioning as modified gills. To absorb atmospheric oxygen, their respiration surfaces must remain continually damp. When exposed to climate-controlled indoor air where relative humidity drops below 50%, their respiratory membranes dry out rapidly. Unable to process oxygen in dry environments, stray wanderers typically die within a day or two of crossing an entryway, leaving brittle, hollow shells scattered across concrete slabs.

Their signature defense mechanism, known as conglobation, allows species within the Armadillidiidae family to tuck their heads and seven pairs of walking legs into an impenetrable, near-perfect sphere. This spherical posture protects their vulnerable soft undercarriages from predaceous spiders and ground beetles while conserving precious body moisture during abrupt drops in environmental humidity.