Discover the rare beauty of our exceptional Oniscus Asellus Occidentalis! These magnificent "Skirted Woodlice" represent one of the most genetically distinct and geographically restricted subspecies in the European isopod world. Smaller, more colorful, and more highly arched than their common cousins, these Atlantic relicts showcase stunning metallic flecks across their distinctive skirted bodies. Perfect for collectors seeking something truly special and scientifically significant in their bioactive setups.
Oniscus Asellus Occidentalis: A Glimpse
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Origin: Southwestern England, Wales, Ireland, Western France
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Scientific Name: Oniscus asellus ssp. occidentalis
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Common Names: Western Skirted Woodlouse, Atlantic Woodlouse
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Difficulty Level: Easy to Medium
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Size: Up to 16 millimeters (smaller than nominate subspecies)
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Rarity: Very Rare (geographically restricted)
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Temperature: 59°F to 77°F
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Humidity: 60% to 75%
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Favourite Foods: Decaying leaves, rotting wood, organic vegetables, protein supplements
An Overview
Originally discovered in the far western reaches of Europe, Oniscus asellus occidentalis represents a fascinating example of ancient genetic divergence and geographic isolation. This remarkable subspecies has evolved separately from the common Oniscus asellus for millennia, developing into a smaller, more colorful, and more highly arched form that has captured the attention of both scientists and hobbyists alike.
What sets these occidentalis specimens apart is their stunning visual appeal and unique body structure. Unlike their widespread relatives, these Atlantic relicts display more vibrant coloration with distinctive metallic flecks that seem to shimmer across their characteristic "skirted" exoskeleton. Their more pronounced arch and compact build give them an elegant, almost prehistoric appearance that must be seen in person to be fully appreciated.
These genetic treasures represent an ancient Atlantic lineage, largely restricted to damp woodlands where they have persisted as relict populations since before the last ice age. Their natural rarity and restricted distribution make them incredibly valuable to serious collectors and researchers studying evolutionary biology and biogeography.
Habitat Requirements
Substrate Mix:
- 35% high-quality coco coir
- 30% composted leaf litter (deciduous mix preferred)
- 20% sphagnum moss for moisture retention
- 10% rotting white wood pieces
- 5% forest soil or earthworm castings
Create a moisture gradient with approximately half the enclosure maintained moist while allowing good drainage. These subspecies prefer the damper conditions typical of their Atlantic woodland origins.
Basic Care
Enclosure Setup:
- Minimum 10-gallon container for small colonies (5-8 individuals)
- Excellent ventilation with multiple air holes
- Deep substrate layer (4-5 inches) to accommodate their burrowing tendencies
- Cork bark flats and natural wood hiding spots
- Thick layer of mixed leaf litter throughout
- Moss patches for microclimate creation
- Shallow water dish in the humid zone
Environmental Conditions:
- Maintain temperature between 59°F to 77°F (they prefer cooler conditions)
- Keep humidity between 60% to 75%
- Provide natural lighting cycle
- Ensure excellent airflow to prevent stagnation
- Monitor regularly as they can be somewhat shy initially
These easy-care isopods are surprisingly hardy and adaptable despite their rarity. They become more active when kept in larger groups and appreciate the cooler, more humid conditions that reflect their Atlantic woodland origins.
Feeding
Primary Diet:
- Mixed deciduous leaf litter (their primary nutrition source)
- Rotting white wood pieces (essential for gut health)
- Fresh organic vegetables (carrot, sweet potato, cucumber)
- Forest moss and lichen when available
- Decaying organic matter of all types
Essential Supplements:
- Protein sources twice weekly (fish food, freeze-dried shrimp)
- Calcium sources (cuttlebone, eggshells, limestone)
- Occasional treats (fruits, specialized isopod foods)
- Shed skin from reptiles and invertebrates
Feeding Schedule: Feed 2-3 times per week with varied offerings. These isopods have hearty appetites and are not particularly picky eaters, showing average feeding response to most organic materials. Always ensure abundant leaf litter is available as their staple food source.
Breeding Information
Oniscus asellus occidentalis are moderate breeders that establish reliable colonies once settled into their environment. Their reproduction rate is fair but not exceptionally fast, making colony establishment a patient process.
Breeding Requirements:
- Stable, cool temperatures (65-70°F optimal)
- Consistent moisture levels with good drainage
- Abundant hiding spots for gravid females
- Rich substrate with diverse organic matter
- Minimal disturbance during breeding seasons
- Adequate space for colony expansion
Females carry their young in brood pouches until well-developed, releasing miniature versions of adults that grow steadily under optimal conditions. The species reaches maturity in 8-12 months, and established colonies can persist for many years with proper care.
Scientific & Conservation Value
These subspecies represent far more than just attractive isopods - they're living pieces of evolutionary history. The occidentalis subspecies is considered a relict Atlantic taxon, meaning it represents an ancient lineage that has survived in isolated pockets while the main species spread across Europe.
Conservation Considerations:
- Threatened by habitat fragmentation in the wild
- At risk from hybridization with common O. asellus asellus
- Represents unique genetic diversity requiring preservation
- Limited to specific damp woodland habitats
- Important for understanding European biogeography
Perfect for:
- Advanced collectors seeking rare subspecies
- Educational displays demonstrating subspecific variation
- Bioactive setups requiring efficient decomposers
- Research projects studying genetic diversity
- Enthusiasts passionate about European fauna
Scientific Significance: The distinction between occidentalis and the nominate subspecies was confirmed through molecular studies showing ancient genetic divergence. Males can be definitively identified by their forked first endopod tip (simple in regular asellus), making this subspecies particularly valuable for taxonomic studies and genetic research.
Whether you're a serious collector fascinated by rare European fauna or a researcher interested in evolutionary biology, our Oniscus asellus occidentalis represent an unparalleled opportunity to work with one of Europe's most scientifically significant isopod subspecies. These Atlantic treasures bring ancient genetic heritage and stunning beauty to the most discerning collections, showcasing the incredible diversity hidden within even familiar species!
