Pleopodal lungs explained

Pleopodal lungs are an anatomical feature of terrestrial isopods and a component of their respiratory system. They are ancestrally derived from pleopodal gills, and they facilitate gas exchange on land. They perform a function similar to spiracles in insects.^{[1] [2]}

Pleopodal lungs are identifiable on woodlice as white patches on the lower five segments (the pleon) on the ventral side (underside). The number of pleopodal lungs varies by species: they may have up to five pairs, or only two pairs as in Porcellio laevis; a minority of species lack pleopodal lungs entirely.

References

1. Web site: Woodlice: 'pleopodal lungs'. British Myriapod and Isopod Group. 2020-04-24.
2. Unwin. Earnest Ewart. 1931. On the structure of the respiratory organs of the terrestrial Isopoda. Papers and Proceedings of the Royal Society of Tasmania. en. 37–104. 0080-4703.