Praunus flexuosus lives along the coast of the north
Atlantic Ocean between
40° north and
71° north, and in the
Baltic Sea. There is only one doubtful record from further south than
Roscoff. It was first discovered in North America in 1960, on the north side of
Cape Cod, and has since colonised as far north as
Nova Scotia. This colonisation may have occurred after
P. flexuosus was transported as a
fouling animal on ships' hulls during the
Second World War. This introduction may also have been facilitated by wartime
convoys (see
Battle of the Atlantic). It is often found on algae, and is most closely associated with the
seaweed Fucus vesiculosus. It lives in shallow water, and is often found around artificial constructions, such as
docks. It is an
omnivore, feeding on
debris and
preying on small crustaceans, especially
harpacticoid copepods,
P. fleuosus is less gregarious than species such as
N. integer. When it detects a predator nearby, using a combination of visual and chemical cues,
P. flexuosus hides among vegetation. ==Life cycle==