Porcellio scaber is a common terrestrial isopod (Phylum Arthropoda, Subphylum Crustacea, Class Malacostraca) that is more closely related to marine shrimp than to insects. P. scaber resembles another local species of isopod called Armadillidium vulgare in appearance but unlike A. vulgare, it cannot roll into a ball when threatened.
Description:
P. scaber has an oval-shaped body that can grow up to 8.5 mm wide and 17 mm long (Riggio 2013). The typically dark gray body is rough in appearance (hence the species name 'scaber'). Like all crustaceans, P. scaber is protected by an exoskeleton that is divided into 3 regions: the head, the thorax and the abdomen (Atwater & Fautin 2001). There are seven thoracic segments, each having a pair of jointed legs of the same size (hence the name isopoda, iso=same, poda=foot). The body of P. scaber is dorso-ventrally flattened, which allows it to scurry easily through leaf litter and clamp tightly against flat surfaces. Male P. scaber can be distinguished from females and juveniles by their more uniform coloration; females and juveniles are usually mottled and lighter in colour (Riggio 2013).
P. scaber detects conditions in its environment using sensory organs located on its head. It has a pair of compound eyes that can sense light and dark (Nemanic 1975), and two pairs of jointed antennae - a small shorter pair used to sense odors (chemoreception), and a longer pair with sensory hair-like structures (setae) used to detect movement (Riggio 2013).
Ecology:
P. scaber is native to temperate terrestrial habitats of Europe but is now widely distributed throughout the world due to human dispersal via wood and leaf matter (Riggio 2013). It is found in damp soil, under leaf litter, rocks and fallen logs in forests, gardens, meadows and saltmarshes. It is susceptible to water loss and consequently many of its behaviours are driven by its need to conserve water (Mckenzie 2011).
P. scaber is a detritivore that feeds mainly on decaying organic matter of both plant and animal origin (Riggio 2013). It therefore plays a role in recycling nutrients while feeding on the microbes associated with decaying organic matter. Predators of P. scaber include spiders, centipeds, birds, ground beetles, shrews and other small mammals. P. scaber will often congregate in groups in cracks and crevices to protect individuals from predation as well as desiccation (Mckenzie 2011; Broly et al. 2012).
P. scaber is a detritivore that feeds mainly on decaying organic matter of both plant and animal origin (Riggio 2013). It therefore plays a role in recycling nutrients while feeding on the microbes associated with decaying organic matter. Predators of P. scaber include spiders, centipeds, birds, ground beetles, shrews and other small mammals. P. scaber will often congregate in groups in cracks and crevices to protect individuals from predation as well as desiccation (Mckenzie 2011; Broly et al. 2012).
Life History:
P. scaber reproduces sexually during the warmer months of spring and summer (Riggio 2013) and may produce up to 3 broods per year. Females carry eggs in a fluid-filled breeding pouch and hatch them into juveniles that look like miniature adults (Riggio 2013; Wright 1997). Following a series of periodic moultings P. scaber reaches sexual maturity within 14 to 22 months after hatching, and lives as long as 2 to 3 years (Riggio 2013; Wright 1997).
References Cited:
Atwater D, Fautin D. 2001. Malacostraca, Animal Diversity Web (online). [accessed 2016 Dec 16]. http://animaldiversity.org/accounts/Malacostraca/.
Broly P, Mullier R, Deneubourg J, Devigne C. 2012. Aggregation in woodlice: social interaction and density . ZooKeys. 176:133-144. [accessed 2013 Jan 31]. http://www.pensoft.net/journals/zookeys/article/2258/.
Mckenzie GJ. 2011. Woodlice Online, SEM Photographs. [accessed 2016 Dec 16]. http://www.porcellio.scaber.org/wlice.htm.
Nemanic P. 1975. Fine structure of the compound eye of Porcellio scaber in light and dark adaptation. Tissue and Cell. 7:453-468.
Riggio C. 2013. Porcellio scaber, Animal Diversity Web (online). [accessed 2016 Dec16].
http://animaldiversity.org/accounts/Porcellio_scaber/.
Wright J. 1997. Pillbugs fact sheet. South Dakota Department of Game, Fish and Parks, Division of Wildlife, Pierre, SD. [accessed 2018 Jan 4]. https://www3.northern.edu/natsource/INVERT1/Pillbu1.htm.
To Learn More:
Dailey TM, Claussen DL, Ladd GB, Buckner ST. 2009. The effects of temperature, desiccation, and body mass on the locomotion of the terrestrial isopod, Porcellio laevis. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 153(2):162-166.
Den Boer PJ. 1962. The ecological significance of activity patterns in the woodlouse Porcellio scaber Latr. (Isopodea). Archives Neerlandaises de Zoologie. 14(3):283-409.
Edney E. 1954. Woodlice and the land habitat. Biological Reviews. 29:185-219.
Gunn DL. 1937. The humidity reactions of the woodlouse, Porcellio scaber (Latreille). Journal of Experimental Biology. 14:178-186.
Horowitz M. 1970. The water balance of the terrestrial isopod Porcellio scaber. Entomologia Experimentalis et Applicata. 13:173-178.
Hughes RN. 1992. Effects of substrate brightness differences on isopod (Porcellio scaber) turning and turn alternation. Behavioural Processes. 27:95-100.
Lindqvist O. 1972. Components of water loss in terrestrial isopods. Physiological Zoology. 45(4):316-324.
McQueen D, Carnio J. 1973. A laboratory study of the effects of some climatic factors on the demography of the terrestrial isopod Porcellio spinicornis. Canadian Journal of Zoology. 52(5):599-611.
Morgado R, Ferreira NGC, Cardoso DN, Soares AMVM, Loureiro S. 2015. Abiotic factors affect the performance of the terrestrial isopod Porcellionides pruinosus. Applied Soil Ecology. 95:161-170.
Newell RC, Wieser W, Pye VI. 1974. Factors affecting oxygen consumption in the woodlouse Porcellio scaber Latr. Oecologia. 16:31-51.
Tanaka K, Udagawa T. 1993. Cold adaptation of the terrestrial isopod, Porcellio scaber, to subnivean environments. Journal of Comparative Physiology B. 163(6):439-444.
Torrey HB, Hays GP. 1914. The role of random movements in the orientation of Porcellio scaber to light. Journal of Animal Behavior. 4:110-120.
Unkiewicz-Winiarczyk A, Gromysz-Kałkowska K. 2012. Effect of temperature on toxicity of deltamethrin and oxygen consumption by Porcellio scaber Latr (Isopoda). Bulletin of Environmental Contamination and Toxicology. 89:960–965.
Warburg MR. 1964. The response of isopods towards temperature, humidity and light. Animal Behavior. 12:175-186.
Broly P, Mullier R, Deneubourg J, Devigne C. 2012. Aggregation in woodlice: social interaction and density . ZooKeys. 176:133-144. [accessed 2013 Jan 31]. http://www.pensoft.net/journals/zookeys/article/2258/.
Mckenzie GJ. 2011. Woodlice Online, SEM Photographs. [accessed 2016 Dec 16]. http://www.porcellio.scaber.org/wlice.htm.
Nemanic P. 1975. Fine structure of the compound eye of Porcellio scaber in light and dark adaptation. Tissue and Cell. 7:453-468.
Riggio C. 2013. Porcellio scaber, Animal Diversity Web (online). [accessed 2016 Dec16].
http://animaldiversity.org/accounts/Porcellio_scaber/.
Wright J. 1997. Pillbugs fact sheet. South Dakota Department of Game, Fish and Parks, Division of Wildlife, Pierre, SD. [accessed 2018 Jan 4]. https://www3.northern.edu/natsource/INVERT1/Pillbu1.htm.
To Learn More:
Dailey TM, Claussen DL, Ladd GB, Buckner ST. 2009. The effects of temperature, desiccation, and body mass on the locomotion of the terrestrial isopod, Porcellio laevis. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology. 153(2):162-166.
Den Boer PJ. 1962. The ecological significance of activity patterns in the woodlouse Porcellio scaber Latr. (Isopodea). Archives Neerlandaises de Zoologie. 14(3):283-409.
Edney E. 1954. Woodlice and the land habitat. Biological Reviews. 29:185-219.
Gunn DL. 1937. The humidity reactions of the woodlouse, Porcellio scaber (Latreille). Journal of Experimental Biology. 14:178-186.
Horowitz M. 1970. The water balance of the terrestrial isopod Porcellio scaber. Entomologia Experimentalis et Applicata. 13:173-178.
Hughes RN. 1992. Effects of substrate brightness differences on isopod (Porcellio scaber) turning and turn alternation. Behavioural Processes. 27:95-100.
Lindqvist O. 1972. Components of water loss in terrestrial isopods. Physiological Zoology. 45(4):316-324.
McQueen D, Carnio J. 1973. A laboratory study of the effects of some climatic factors on the demography of the terrestrial isopod Porcellio spinicornis. Canadian Journal of Zoology. 52(5):599-611.
Morgado R, Ferreira NGC, Cardoso DN, Soares AMVM, Loureiro S. 2015. Abiotic factors affect the performance of the terrestrial isopod Porcellionides pruinosus. Applied Soil Ecology. 95:161-170.
Newell RC, Wieser W, Pye VI. 1974. Factors affecting oxygen consumption in the woodlouse Porcellio scaber Latr. Oecologia. 16:31-51.
Tanaka K, Udagawa T. 1993. Cold adaptation of the terrestrial isopod, Porcellio scaber, to subnivean environments. Journal of Comparative Physiology B. 163(6):439-444.
Torrey HB, Hays GP. 1914. The role of random movements in the orientation of Porcellio scaber to light. Journal of Animal Behavior. 4:110-120.
Unkiewicz-Winiarczyk A, Gromysz-Kałkowska K. 2012. Effect of temperature on toxicity of deltamethrin and oxygen consumption by Porcellio scaber Latr (Isopoda). Bulletin of Environmental Contamination and Toxicology. 89:960–965.
Warburg MR. 1964. The response of isopods towards temperature, humidity and light. Animal Behavior. 12:175-186.