Although their common names contain the word “bug,” sowbugs and pillbugs are not really bugs. They’re crustaceans, mostly aquatic invertebrates, such as the crab, lobster, crayfish and barnacle. Crustaceans breathe through gills
so they are restricted to areas with high humidity. They have a hard exoskeleton and jointed appendages. Sowbugs and pillbugs are in the order Isopoda. They are technically termed isopods, which means “the legs are alike.” Sowbugs and pillbugs are found in most regions of the world, and are widespread throughout North America.
Both sowbugs and pillbugs mate throughout the year, with most
activity in the spring.
They are easy to breed.
On the underside
between the second and fifth pair of legs, females have leaf-like growths at
the base of some legs known as a marsupium or brood pouch. These brood pouches hold
up to 100 developing eggs and embryos.
Two to three broods
consisting of 30-40 young are incubated in the brood pouch. Eggs
hatch in three to seven weeks and the young are white-colored. They
remain in the brood pouch for six to eight weeks until they are able
to take care of themselves. There may be one to two generations per
year, with individuals living up to three years depending on weather
The first two appendages on the male abdomen are modified as elongated copulatory organs.
Some species roll up into a ball when disturbed. Juveniles look like adults and are soon liberated from
the brood pouch. Molting is in two stages. First the back half molts, then two to three days later, the front half molts. Coloration of both halves may be different at this time.
Sowbugs and pillbugs, are cold-blooded. Their body temperature is regulated by the temperature of their environment.
Each family has a chemical "badge" which distinguishes it
from the rest of the population (Linsenmair 1984).
Females often carry sperm from more than one male. Therefore broods
of one female can be multi-paternal (Sassaman 1978).
Some species reproduce
parthenogenically. Eggs develop without
the benefit of fertilization (Scarab Crawford)
Sowbugs and pillbugs are oval or slightly elongated with a flattened
body and up to 3/4 inch long. They are wingless, brownish or slate
gray, and possess well-developed eyes, seven pairs of legs and
overlapping "armored" plates that make them look like little
armadillos. Sowbugs have two tail-like structures on the rear end.
Pillbugs are similar, except they lack the tail-like appendages and
can roll up into a tight ball.
Myths, Legends, and Folklore
some parts of the world, it is believed that eating pillbugs can help ease upset stomachs. Although not proven,
this might be true because pillbug shells are high in