Nature Gardens Pill Bugs

An Introduction

Both the common pill bug and the common rough woodlouse are originally from southern Europe and northern Africa. Before Europeans arrived on this continent neither of them lived here. Both species are associates of plants, living in soil and leaf litter, and have hitched rides from Europe to the U.S. with a little help from us. One possible explanation is the importation of plants and associated soil that began steadily streaming into ports-of-call as the continent was settled. A more interesting, and might I say apocryphal story, unfolds if we look to the high seas.

Two if by Sea

Image courtesy of the Library of Congress

In the days of wayfaring seamen and wooden ships, soil and boulders were used as ballast, to ensure a properly balanced vessel. This earthen ballast would be discarded when it was time to fill the holds with precious cargo and booty. It is not so much of a stretch to think that in some instances surviving creatures, eggs, seeds, and more managed to colonize the shores of these new lands. Whatever the mode of their introduction, it is clear that they were introduced more than once and in multiple locations. Today these creatures are widespread throughout the world and are a very common sight in L.A.'s parks, backyards, and even the museum grounds! Special thanks to Dr. Regina Wetzer, Director of the Marine Biodiversity Center, for identification.