Pirate spider
Ero furcata
Pirate spiders of the genus Ero are highly specialized predators that feed almost exclusively on other web-building spiders. They do not build their own capture webs but instead invade foreign webs and mimic prey signals. Their bodies are typically brownish with distinct patterns and characteristic humps on the abdomen.
Details
Identification
Row of long, curved macrosetae on the front legs (tibiae and metatarsi); two distinct humps on the opisthosoma.
Social behavior
Solitary and highly aggressive towards other spiders.
Diet
Specialized araneophages; they primarily feed on cobweb spiders (Theridiidae) and sheet weavers (Linyphiidae).
Hunting strategy
Aggressive mimicry: They pluck the silk threads of the prey's web to simulate a trapped insect or a potential mate.
Spawning substrate
Eggs are placed in a characteristic, stalked cocoon suspended from vegetation.
Overwintering
Overwintering usually occurs as a juvenile or in the egg stage within the cocoon.
Ecology
Ecological role
Top predators within the spider community; they regulate populations of other spider species.
Natural predators
Birds, ichneumon wasps (parasitoids of the cocoons), larger predatory insects.
Competitor species
Other pirate spider species or intraguild predatory spiders.
Ecosystem service
Biological pest control indirectly through the regulation of spider populations.
Threats
Intensification of agriculture, use of broad-spectrum insecticides, loss of hedgerows and field margins.
Scientific profile
Profile
Distinguishing features
Characteristic are two distinct humps on the upper side of the abdomen (opisthosoma). The front legs bear a specialized row of long and short curved spines (macrosetae) on the metatarsus and tibia, used for grasping prey spiders. The egg sac is pear-shaped and suspended by a long stalk.
Habitat
Structurally rich habitats such as forest edges, hedges, bushes, but also damp meadows and gardens. It occurs in both the herb layer and low tree canopies.
Role in food web
Specialized higher-order predator (secondary consumer) that regulates the density of other spider populations.
Protection & threats
Main threats
Loss of edge structures in the landscape (hedges, forest fringes) due to intensive agriculture; use of broad-spectrum insecticides that reduce the food supply (other spiders).
Population trend
Stable; the species is widespread in Central Europe and is considered 'Least Concern' according to the German Red List.