Both sowbugs and pillbugs are common outdoor and occasional indoor pests. You’d probably prefer both to stay out of your garage, garden, or cellar. So, what are the real differences between sowbugs and pillbugs—and what should you do if you have an infestation? We’ll delve into all of the similarities (and a few key differences) between sowbugs and pillbugs.

pill bug

They have the same lifecycle

Pillbugs and sowbugs are actually arthropods, like insects, but they are crustaceans like crabs and lobsters. They all start their lifecycle as eggs. Adult females carry these eggs in a “marsupium” or pouch on their underside surface, per a University of Florida Exten sion fact sheet. Both pillbugs and sowbugs undergo their immature cycle in their mother’s pouch. Once they leave the marsupium, they may go through several molting stages, which allow them to continue to develop until they are adults.

Pillbugs and Sowbugs differ in appearance

While still quite small, pillbugs may measure slightly longer than sowbugs. Per the University of Kentucky, pillbugs average between 1/3 and 2/3 inches in length, while sowbugs measure between 1/4 and 1/2 inches. Both live as adults, on average, be tween two and five years. They both have antennae and sowbugs have pointy “tails” on the other end of their body.

Pillbugs and Sowbugs both prefer damp habitats

Both pillbugs and sowbugs are at risk of drying out if they don’t find water for extended periods of time. They’re likely to burrow in “dry” but moist places such as in soil, mulch, and potted plants, or hide under building foundations or in sidewalks.

As land crustaceans, both of these arthropods have gills and need moist habitats to survive, however, according to the Missouri Department of Conservation, they’ll drown if fully submerged in water for an extended period of time.

They have similar diets

Pillbugs and sowbugs feast on decaying plant material (like rotting wood or fungi) and tender living plants. According to Texas A&M’s Field Guide to Common Texas Insects, both are nocturnal and typically feed at night, Their diet actually contributes to organic decomposition and soil fertility, making pillbugs and sowbugs a beneficial species outside of the home. Land crustaceans like pillbugs and sowbugs are a key part of the food chain as well, and are eaten by multiple predators including spiders, beetles, and centipedes .

They have one key difference

While pillbugs are commonly called “roly-polies,” sowbugs can’t adopt the same nickname. Pillbugs can roll into a ball (something they typically do when threatened), while sowbugs cannot. Sowbugs are flatter, have appendages, and extend farther to prevent them from rolling into a ball. Sowbugs also have their aforementioned “tails'' on one end and noticeable antennae on the other end , while pillbugs have only the noticeable antennae.

How to manage pillbugs and sowbugs in your home

It’s best to consider long-term solutions to prev ent sowbug or pillbug infestations. Correcting the habitats that foster these intruders is key. Thick ground coverage, like ivy, acts as a hiding spot for these pests, as do lumber and damp, stored garden materials (your best bet is to keep these things stacked away from your house or building).