Black dwarf spider
Dicymbium nigrum
The black dwarf spider is a small member of the Linyphiidae family, widely distributed across Central Europe and parts of Asia. Its body is predominantly black and shiny, while the legs typically exhibit a lighter, yellowish-brown coloration. A notable feature is the distinct sexual dimorphism, with males possessing two characteristic lobes on their cephalic region. It primarily inhabits the herb layer and leaf litter in moist environments such as meadows and forests.
Details
Identification
Shiny black cephalothorax and abdomen; legs yellow-orange to brown; males with a bipartite cephalic lobe.
Social behavior
Like most dwarf spiders, this species is solitary and exhibits territorial behavior near its web.
Diet
The species is predatory, feeding on very small invertebrates, especially springtails (Collembola) and small flies.
Hunting strategy
Construction of tiny sheet webs close to the ground to catch soil-dwelling insects.
Spawning substrate
Egg sacs are attached to the leaf litter or low-growing vegetation.
Overwintering
Overwintering usually occurs in the adult or subadult stage within the protective leaf litter.
Ecology
Ecological role
Important regulator of micro-insect populations within the soil fauna.
Natural predators
Larger spiders, ground beetles, predatory bugs, and small insectivorous birds.
Competitor species
Other species of the genus Dicymbium and other small linyphiids.
Ecosystem service
Contribution to biological pest control in agricultural and forestry areas.
Threats
Intensification of agriculture, use of pesticides, and drainage of wet meadows.
Scientific profile
Profile
Distinguishing features
Males possess a characteristic cephalic modification with two distinct lobes, explaining the name 'two-fronted'. Unlike the very similar species Dicymbium tibiale, the tibia of the first leg pair in D. nigrum males is not thickened. Identification of females is primarily based on the structure of the epigyne (copulatory openings).
Habitat
Diverse open to semi-open habitats, including meadows, pastures, ruderal areas, forest edges, and hedgerows; often found in the herb layer or leaf litter.
Role in food web
Important predator of micro-arthropods in the soil layer; serves as a food source for larger spiders, predatory beetles, and insectivorous birds.
Protection & threats
Main threats
Intensification of agriculture (especially frequent mowing and high pesticide use), large-scale soil sealing of open land, and loss of edge structures.
Population trend
Stable; the species is widespread in Central Europe and regularly and frequently encountered in suitable habitats.