Survival and precopulatory behaviour of Gammarus pulex (L.) exposed to two xenoestrogens

The effects of the xenoestrogens ethinylestradiol (EE) and bisphenol A (BPA) on the survival and reproductive behaviour of the amphipod Gammarus pulex were determined in a series of bioassays. Acute toxicity of the test chemicals was determined under static conditions, revealing 10 d median lethal concentrations (LC50s) of 0.84 and 1.49 mg/L for EE and BPA, respectively. Several aspects of the reproductive behaviour including the ability of males and females to detect each other, form precopulatory guarding pairs and to continue the guarding behaviour, were examined during a 24 h exposure period over a wide range of concentrations. However, reproductive behaviour was only disrupted at relatively high concentrations where it would be unrealistic to attribute the effects to an endocrine mediated process. Consequently, changes in precopulatory guarding resulting from acute exposure, do not seem to be suitable for detecting the presence in water of xenoestrogens known to cause endocrine disruption in vertebrates.