Blue star vs Common Rough Woodlouse

Amsonia orientalis compared with Porcellio scaber

Key Differences

• Blue star is Critically Endangered while Common Rough Woodlouse is Least Concern.

Taxonomic Classification

Rank	Blue star	Common Rough Woodlouse
Kingdom	Plantae (Plants)	Animalia (Animals)
Phylum	Magnoliophyta (Flowering Plants)	Arthropoda (Arthropods)
Class	Magnoliopsida (Dicots)	Malacostraca (Crustaceans)
Order	Gentianales (Gentianales)	Isopoda (Isopoda)
Family	Apocynaceae	Porcellionidae
Genus	Amsonia	Porcellio
Species	Amsonia orientalis	Porcellio scaber

Conservation Status

Blue star

CR — Critically Endangered

Common Rough Woodlouse

LC — Least Concern

Physical Characteristics

Attribute	Blue star	Common Rough Woodlouse
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Blue star

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Common Rough Woodlouse

Habitat

Found across multiple habitat types including tropical and subtropical moist broadleaf forests, tropical and subtropical dry broadleaf forests, and deserts and xeric shrublands within the Indomalayan biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Widely distributed across Africa (South Africa), Asia (Japan, Sri Lanka), Europe (5 countries), North America (United States), and South America (Brazil).

Blue star

The Blue star (Amsonia orientalis) is a species in the genus Amsonia. It is currently classified as Critically Endangered on the IUCN Red List. Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Common Rough Woodlouse

<em>Porcellio scaber</em>, the common rough woodlouse, is a terrestrial isopod crustacean in the family Porcellionidae. One of the most widespread and abundant woodlouse species in the world, it has established itself across Europe, the Americas, Asia, Australia, and numerous oceanic islands, including populations documented in Belgium, Brazil, Denmark, Japan, and Norway. This synanthropic species typically inhabits decaying leaf litter, rotting wood, compost heaps, under stones, and in the soil of gardens, forests, and human-modified landscapes. It thrives in moist, sheltered microhabitats and shows some tolerance for drier conditions compared to related species. As a detritivore, the common rough woodlouse feeds primarily on decaying organic matter including leaf litter, rotting wood, fungi, and plant debris, playing a significant role in nutrient cycling and decomposition processes. The species reproduces sexually, with females brooding eggs and juveniles in a specialized brood pouch. Assessed as Least Concern by the IUCN, its cosmopolitan distribution and high adaptability make it one of the most ecologically resilient terrestrial isopods. It is easily identified by its rough, grey to dark brown dorsal surface with pale lateral markings. Biological traits such as average lifespan and typical body length remain variable across populations and are not uniformly documented in standardized databases.