Roly-polies: perfect pills for your garden

I was moving stones in my backyard yesterday and had to stop because I was disrupting the lives of too many pill bugs. I love these animals—they are like little armadillos because they can roll up into little armored balls. When I researched them for my book, Our School Garden!, I was amazed by all the different names that they had: Some of my favorites are: butcher boy, gramersow and slater, along with the ones I use in my poem—potato bug, cheese log, doodlebug and chucky pig. Most of the kids I know around here call them roly-polies.

            Pill bugs are primarily detritivores.  That means they eat dead vegetation and dead animals. They also eat mold and fungi and some living plants. When they eat living plants they prefer to eat young and tender shoots and fruit such as strawberries. Pill bugs are considered beneficial animals for the garden. Like earthworms, they mostly feed on dead vegetation and help turn it into soil by breaking it down during their digestion process.

A great fact for kids is that pill bugs are coprophagous animals. That means that they eat their own feces. Copper is an essential element in their blood and they need to eat food with copper in order to survive. Decaying leaves are a good source of copper. Pill bug feces are rich in copper, too. When there isn’t a good supply of decaying leaves to eat, pill bugs will recycle their own copper.

That makes them useful to pet owners. They put pill bugs in cages with their pet reptiles, insects or tarantulas. The pill bugs eat the feces, mold and dead vegetation and help keep the cage clean. Depending upon the type of animal in the cage, some of the pill bugs end up being part of the pet’s diet!

            Female pill bugs have pouches a lot like kangaroos. Usually a male fertilizes a female pill bug’s eggs, but pill bugs occasionally reproduce through parthenogenesis–forming young from unfertilized eggs. In both cases the female forms a pouch around the eggs to protect them. The female has from a dozen to two hundred eggs at a time. She carries them in her pouch for two to three months.

When pill bugs hatch they look just like small light-colored adults. They are born with only six pairs of legs. Several days to several weeks after they hatch the babies molt, shedding their first shell that they have already outgrown. Now they have seven pairs of legs. It is time to leave the pouch.

Their shells won’t have hardened yet. They cannot protect themselves from predators like spiders, lizards or toads. It is also easy for them to dry out. As a result, there is a very high mortality rate at first. Pill bugs that survive are able to breed at about one year of age. The females carry one to three sets of eggs each year. Pill bugs can live from two to five years.

They are found all over the world. Look for them in your yard!