Arthropod Order Isopoda (Sowbugs)

Sowbugs are not quite as prolific or as important as scuds (Amphipoda), but in certain waters they are more common and serve the same role.

They should not be imitated with the same patterns because they are much more wide and tend to sprawl their legs to the side instead of tucking them neatly under the body. They crawl around instead of swimming, so they are probably best imitated with a dead-drift.

They produce new broods once every two months, allowing them to populate a stream very quickly if enough food is there to support them.

This order also includes popular terrestrial species commonly known as pillbugs or rolly polies. They aren't known to be relevant to fly fishermen.