Size
Adult body length is approximately 3.5–3.9 mm, with males generally smaller than females.
Identification
Males have a large spur or "horn" projecting from the anterior surface of the first cheliceral segment; females do not have this feature. 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 their chelicerae and the anterior end of the dorsal surface of the body.
Range
Holarctic. Invasive in North America.
Habitat
Common in disturbed, anthropogenic habitats (e.g., agricultural fields, urban areas).
Food
Soft-bodied animals such as aphids, caterpillars, leafhoppers, beetle larvae, mites, slugs, etc. Also known to scavenge on various arthropods, including hard-bodied animals.
Life Cycle
In Europe P. opilio has a single generation per year 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.
Remarks
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.
