In a contest for the most beloved bug of childhood, the roly-poly would undoubtedly be in the running for the blue ribbon. Kids love them because they are interactive but not aggressive. A slight nudge causes a roly-poly to roll up into a ball. Scoop one up for a closer look, and, after a few moments of stillness, the roly-poly will unfurl and begin to crawl and explore your palm.
Although also called doodlebugs and pill bugs, roly-polies are not insects. They have more in common with shrimp, crab, and lobster, and are in fact crustaceans—the only crustacean species that lives out of water.
Roly-polies breathe with gills that must be continuously wet but not too wet. They prefer moist, shady environments such as under rocks, among rotting leaves, and wood and compost piles. Because moisture is precious, roly-polies tend to be nocturnal. They prefer the low light of an early morning or a cloudy day. In hot weather, they might be found in large groups attempting to conserve moisture.
The roly-poly’s proper name is armadillidiidae. Pronounced arm-uh-dill-uh-DI-uh-DEE, the name sounds a lot like armadillo, which means “little armored one.” Like the nine-banded armadillo that reigns as the small state mammal of Texas, the roly-poly has a protective shell. Unlike the armadillo, the roly-poly can completely roll up into a ball, which is called conglobation.
The balling ability is one of its few defensive mechanisms. The roly-poly also has special glands that release a stinky secretion and a natural, dark-gray camouflage. As you can imagine, roly-polies are prey for anything ready for a snack.
ROLY-POLY PARTS
These tiny tanks have a small head with two pairs of antenna used to “smell,” two eyes that only detect light and dark, and a mouth that can only eat soft matter. The seven-segmented mid-section, or pereon, has overlapping plates and seven pairs of walking legs. The roly-poly’s underside is fairly hollow. The rear section consists of the pleon, which contains the breathing gills, and the uropod—special parts that wick up water. It can drink from both ends!
ROLY-POLY REPRODUCTION
The harmless creatures come out to fulfill their essential role in the ecosystem as soon as the weather warms. Breeding season arrives with spring. The female roly-poly has a brood pouch similar to a possum’s, where she deposits her eggs when ready to mate. The male, picking up on this readiness via scent, comes a-calling.
The eggs hatch two months after fertilization. Babies remain in the pouch for several days before emerging. The young are light-colored, micro-versions of the adults. They leave the pouch but stay near mom for a bit before striking out on their own. Roly-polies can have two or three broods a year, with around 200 babies each time. Only a fraction of each brood survives to adulthood.
A WIN-WIN SITUATION
The roly-poly’s dinner menu is what makes this crawling critter an essential part of a healthy ecosystem. The presence of pill bugs on your property is a good indicator of healthy soil.
A roly-poly’s diet is about 90 percent rotting organic matter, like wood and plants. The other 10 percent of their diet is their own poop. They can go almost three months without eating as long as they have proper moisture. In times of drought, they nibble on roots, stems, leaves, and fruit.
Normally, a pill bug in your house is a bad sign of too much indoor moisture. Roly-polies are found in homes more often these days as pets and are even available online. One website priced a classic colony of 15 armadillidiidae at $12. The terrarium to keep them costs $19.99. Other roly-poly varieties were also available, all at different prices and numbers.
Of course, the cheapest way to make a roly-poly your pet is to find one in your backyard or a park and scoop it into any see-through container you can put air holes in. Your home-made terrarium should have a small rock for a place to hide and a small piece of damp cardboard for moisture.
One drawback is that these land-based crustaceans won’t live long in an artificial environment. On their own, they can live up to three years.
DOODLEBUG DETAILS
- Roly-polies are land-living crustaceans.
- In the winter, they hibernate just below the soil’s surface or under boards or other debris.
- Their shells don’t grow; they molt.
- The tiny bugs travel about 42 feet a day on warm days and 19 feet a day on cold days.
- They find food and mates by scent.
- They differ from sow bugs, which have a more flattened tail and cannot roll into a ball.
- Roly-polies are native to the Mediterranean, where they don’t have to hibernate.
