An explanation for the compass rose pattern

The woodlouse Trichoniscoides saeroeensis was collected from a mine adit near the shore at Langness, Isle of Man. The record supports the contention that the species is cavernicolous in the British Isles. Field evidence points to the woodlouse being exceptionally tolerant of water, and this may partly explain its ability to survive in subterranean habitats. These observations add weight to the contention that the species is an example of a coastal invertebrate that is expanding its range by colonising the hypogean, an evolutionary route that may have been followed by some other terrestrial cave invertebrates.