The Roller Girls
Kelly’s Field Notes
Our guest on this episode is Dr. Scott Kight, the Associate Dean of Student Affairs for the College of Science and Mathematics at Montclair State University in Montclair, New Jersey. Scott was Kelly’s M.S. advisor and is on her doctoral committee!
Scott’s Profile Page at Montclair State - https://www.montclair.edu/profilepages/view_profile.php?username=kights
Scott’s ResearchGate Page - https://www.researchgate.net/profile/Scott-Kight
Common Name: Roly-poly, Potato Bug, Wood Louse, Slater, Sow Bug, Pill Bug, and so many more!
Order: Isopoda
Suborder: Oniscidea
Species of Note (There are over 3700 species of terrestrial isopod belonging to 37 families):
Common pill bug (Armadillidium vulgare) - the most popular research species! Found throughout Europe and North America. The sort of classic species when you think of terrestrial isopods. This is a “roller.”
Smooth slater (Porcellio laevis) - fast! They move in quick bursts and cannot roll. Found throughout Australia, Europe, North and South America, and Asia. Likely originated in Northern Africa. This is a “runner.”
Description:
Terrestrial isopods range in size from 8.5 mm to 17 mm (about 3/8 to 9/16 of an inch). In the wild, they are generally grey or brown in color. They come in two types: runners and rollers. Runners, often called sow bugs, cannot roll up for protection so instead tend to be very fast and fairly flat so they can slip into small spaces. Rollers, often called roly-polies, can roll up or “conglobate” for protection. Their cuticle (covering) is tougher than runners and they move at slower speeds.
Life Cycle:
Terrestrial isopods are crustaceans! While they live on land, they breathe through gills and require high humidity in their habitats. Life begins for a terrestrial isopod as an egg, carried in its mother’s marsupial pouch. Once they hatch the mother will carry her young in her pouch for about 2 months. Here they will feed on a nutritive fluid their mother creates. It’ll take about a year for the young to reach adulthood.
Distribution:
Terrestrial isopods have a worldwide distribution! They are found in most habitats, only missing from polar regions and high altitudes. They have been spread far and wide by commerce, for example they are not native to North or South America.
Super Powers:
Conglobation - some terrestrial isopods can roll up into a ball for protection
Swift - sow bugs are fast runners
Armor - the terrestrial isopod’s cuticle is strong and difficult to penetrate. So much so a spider, the woodlouse hunter spider (Dysdera crocata), has specialized chelicerae (jaws) for piercing their armor.
Terrestrial Isopods in Culture:
Because they are easy to raise, adorable, don’t carry disease, and cannot hurt you terrestrial isopods are often kept as pets!
Terrestrial isopods have been bred to come in many colors and patterns through the pet trade.
References:
“Armadillidium Vulgare.” Wikipedia, 18 Sept. 2020, en.wikipedia.org/wiki/Armadillidium_vulgare.
Hetzler, Paul, et al. “Pill Bugs: The Not Overtly Unpleasant Invasive.” NCPR, 4 July 2020, www.northcountrypublicradio.org/news/story/41825/20200704/pill-bugs-the-not-overtly-unpleasant-invasive.
“Pillbugs, Vol. 6, No. 24 | Mississippi State University Extension Service.” Extension.msstate.edu, extension.msstate.edu/newsletters/bug%E2%80%99s-eye-view/2020/pillbugs-vol-6-no-24. Accessed 2 Dec. 2023.
“Porcellio Laevis.” Wikipedia, 27 May 2021, en.wikipedia.org/wiki/Porcellio_laevis.
Sfenthourakis, Spyros, and Elisabeth Hornung. "Isopod distribution and climate change." ZooKeys 801 (2018): 25.
“Sowbugs, Pillbugs.” Texasinsects.tamu.edu, texasinsects.tamu.edu/sowbugs-pillbugs/.