Electroantennogram measurement of the olfactory response of Daphnia spp. and its impairment by waterborne copper

In this study an electroantennogram (EAG) method was developed for use on live daphniids. The EAG response of Daphnia magna and Daphnia pulex to a variety of amino acids was measured. The strongest response measured was elicited by L-arginine and was shown to induce a concentration-dependent response indicating the response is olfactory in nature. Subsequent exposures of D. magna to a low, ecologically-relevant concentration of copper (7.5 μg/L) showed a disruption in EAG function. This study utilizes the development of an EAG method for measuring olfactory acuity of live daphniids and demonstrates that at ecologically-relevant concentrations, the olfactory dysfunction caused by copper can be detected. The EAG technique is a useful tool for investigating the olfactory response of daphniids to odourants at the cellular level and detecting the effects of toxicants on the olfactory acuity of daphniids.

► The electroantennogram (EAG) is a viable method for measuring the olfactory response of live daphniids to amino acids.
► Both Daphnia magna and Daphnia pulex responded greatest to amino acid L-arginine.
► Exposure to copper at an ecologically relevant concentration impaired the chemosensation of D. magna by more than 50 percent.
► The EAG can be used in ecological risk assessment of contaminants in aquatic environments on the olfaction of daphniids.