What Happened to Rollie Pollies? Here's Why Pill Bugs Are So Important for the Environment

If your childhood was like mine, you spent many summer days digging under garden stones for insects to fill your bug jar. Of all the many backyard bugs, however, the most common were always the rollie pollies. As benign as they were plentiful, these innocuous insects were a mainstay of our suburban backyard, until one day, they weren’t. Like bees, rollie pollie numbers had evidently dwindled, and whether by age or something else, encounters with these critters became more infrequent. Which begs the question, what happened to rollie pollies?

Rollie pollies are known by many names: pill bugs, slaters, doodle bus, armadillo bugs, and, if you’re from my particular Long Island suburb, “potato bugs.” The spelling of "rollie pollies" also varies depending who you ask — roly pollies, rolly pollies, and roly polies all seem to be accepted variants.

But a rose by any other name still curls up into a ball as a defensive mechanism. Rollie pollies are actually a member of the crustacean family of isopods, and they can trace their lineage back to the time before the dinosaurs. Think of them as little, harmless trilobites. 

Though they are technically considered woodlice, it would be more apt to think of rollie pollies as wood shrimp, at least according to Jonathan Wright, a professor of biology at Pomona College who studies the little buggers. Like their ocean-dwelling relatives, pill bugs actually have gills made of a mucus membrane that absorbs oxygen from water. Since they live on land, rollie pollies need to stay in damp, moist areas like beneath fallen logs. If they dry out, they suffocate. 

The short answer is, nothing really happened to them. In fact, chances are good you haven’t really gone out looking under any garden rocks in recent years. If you had, you might have noticed more rollie pollies one season and less the next. It all depends on dryness and soil quality. The drier the season, the fewer pill bugs you’re likely to see. If you have healthy soil, you’re also likely to see more of them than you might have a few years ago. 

There are plenty of ways to prepare your soil for gardening that will also make it more inviting for other organisms like earthworms and rollie pollies. And as much as rollie pollies can be garden pests sometimes, there is plenty of evidence out there to support the idea that they are quite good for the environment — even on a large scale.

Rollie pollies actually contribute greatly to the ecosystem. They are decomposers, feeding on decomposed leaf litter and wood fibers, as well as stems, roots, shoots, fruits, and tubers. Some pill bugs have been known to eat decaying animal flesh or feces, as well as shed snakeskin and other dead insects. On top of all that, they are also prey animals and serve as a ready food source for birds, toads, spiders, wasps, and centipedes. 

According to Green Living Journal, the living situations and diets of these bugs allow them to temporarily remove many of the toxic metal ions from the soil where they dwell. Now, those toxic metals are returned to the soil when they die, of course, but their existence within the animals has given scientists a clue to potential pollutants they might not have otherwise known about. 

In fact, a 1986 study revealed that rollie pollies in England were found to have high levels of copper, zinc, and cadmium deposits in their midgut. In order for this to happen, the levels of these metals in the soil would have to be abnormally high. The cause of this was found to be pollution, which scientists at the time had not even considered to be a problem, at least not in terms of actual English soil, anyway.

We’re not sure if you know about this but our planet does have kind of a climate issue going on these days. According to a study conducted in 2015 by Yale and other universities, rollie pollies have a role in controlling global climate and might even be helpful in fixing some of our environmental issues. The study revealed that a specific fungus in the soil was responsible for releasing excess carbon dioxide into the atmosphere. 

The warmer the atmosphere becomes, the more the fungus’ activity increases, resulting in more carbon and even higher atmospheric temperatures. It’s a vicious cycle and one that the rollie pollies are actually helping to slow down. Pill bugs eat the fungus, thereby mitigating the effects of increased carbon and temperature. It’s a small thing, but with the planet warming more every year, every little bit of help counts.