Littoral Distribution of Lumbricillus reynoldsoni Backlund and Other Enchytraeidae (Oligochaeta) in Relation to Salinity and Other Factors

Abstract

The distribution of littoral Enchytraeidae was determined on an Anglesey beach by means of baited bags. L. reynoldsoni was found chiefly above the Pelvetia zone, while L. lineatus was more widely distributed. The salinity preferenda of these two species were determined by means of multiple-choice chambers, in which different salinity regimes were maintained on moist blotting paper balls. L. reynoldsoni was found to prefer salinities less than half that of the seawater, while L. lineatus displayed no preference over a range from distilled water to a salinity 1.5 x that of the sea-water. Both species showed marked tolerance for sea-water. L. reynoldsoni was apparently unable to prevent water loss when transferred from a weaker to a stronger strength of sea-water. Fluids collected from the upper shore on absorbent cotton pads were found to have generally low osmotic pressures, depending upon rainfall. L. reynoldsoni was found to be attracted to both fresh and decayed seaweed. It is concluded that the distribution of this species is governed by low salinities and the presence of a drift-line of sea-weed. Pe3ioMe