Fig. 5: Apparent decrease in air volume calculated from the decrease in buoyant force in the body of E. horridus during 3 h submerging period under water with different treatments.

A Exemplary progression curves of the decrease of air volume in the body of one louse in 10 min intervals over a period of 3 h. Black dots and line represent the “natural” condition (exposure to Baltic Sea water), dotted circles and line the exposure to 0.1% Triton X solution in Baltic Sea water, and grey triangles and line symbolize the exposition to Baltic Sea water after contact to Triton X and a 3 h washing period. B Total decrease of air volume in µl in the body of the lice (n = 13) for the three different treatments (“Natural”, “Triton”, and “Washed”). Each louse was measured 3 h for each treatment on three consecutive days. The boxes indicate 25 and 75th percentiles, the line within the boxes represents the median, red triangles show the mean values, and whiskers (error bars) define the 10 and 90th percentiles. All data points are plotted.