Year-class-splitting
Guides
Philoscia muscorum
Common Striped Woodlouse, Fast Woodlouse
Philoscia muscorum is a common European woodlouse notable for its rapid movement and distinctive appearance. It exhibits a unique life history strategy called year class splitting, where individuals from the same reproductive cohort diverge into two developmental pathways: faster-growing individuals mature and reproduce in their first year, while slower-growing individuals delay maturation until their second year. This species has successfully established introduced populations in eastern North America, including New England, the mid-Atlantic states, and the Pacific Northwest.