Effect of 17α-Ethinylestradiol on the Time Needed for Males and Females of Gammarus tigrinus Sexton, 1939 to Re-couple

Abstract

The aim of presented study was to determine the behavioural response of precopulatory pairs of Gammarus tigrinus exposed to the 17α-ethinylestradiol (EE2). It was hypothesized that 17α-ethinylestradiol would increase the time needed for a male to re-capture a female. Hypothesis was tested in a laboratory with 20 precopula pairs exposed to different treatment conditions. Paired animals were exposed to two different compound concentrations of 50 ng·L-1 and 500 ng·L-1. The control and solvent control was artificial sea water and artificial sea water with ethanol (the diluent for EE2). The couples were tested several times under different experimental treatments. The obtained results indicate that EE2 affects the precopulatory mate guarding behaviour of Gammarus tigrinus. EE2 in concentration of 50 ng·L-1 and 500 ng·L-1 prolonged the time needed for re-pairing. However, relative to the controls only EE2 in concentration of 500 ng·L-1 significantly prolonged the time needed for male-female re-coupling. In summary, EE2 affects