Species Phalangium opilio

Phalangium opilio Linnaeus 1758

Adult body ~3.5–3.9 mm, with males generally smaller than females

Males have a large spur/horn on the anterior surface of the first cheliceral segment. Males also tend to have long, thin pedipalps relative to those of other harvestmen.

Both sexes have small tubercule-mounted spikes on the anterior surface of their body, in between the top of chelicerae and the anterior end of the dorsum.

Holarctic, native to the Palaearctic. It has been introduced to North America, North Africa and New Zealand.

Common in disturbed, anthropogenic habitats (e.g., agricultural fields, urban areas).

Soft-bodied animals such as aphids, caterpillars, leafhoppers, beetle larvae, mites, slugs, etc. Also known to scavenge on various arthropods, including hard-bodied animals.

In Europe has a single generation and overwinters as eggs. In parts of North America two or more generations may occur, and eggs, immatures, or adults may overwinter. Eggs are laid in moist areas under rocks, in cracks in the soil, or between the soil and the crowns or recumbent leaves of plants. The eggs hatch in three weeks to five months or more, depending on temperature, and the immatures undergo several molts and reach maturity in two to three months, again depending on temperature.

Due to its extensive range and ubiquity in anthropogenic habitats, this species is the single-most studied opilionid; several hundred articles have been published on it.