Figure 1

Olfactory responses of male tilapia to different stimuli. On the left hand-side, typical electro-olfactograms (EOGs) recorded in response to different stimuli: in blue – controls for normalization – serine (S) and blank (B); in pink – male urine (1:10000) – from dominant (DOM) and subordinate (SUB) males; in light green – extracts of female water (1:1000) – from pre-ovulatory (PRE) and post-ovulatory (POST) females. On the top-half on right hand side, normalized EOG amplitudes (mean ± SEM) elicited by all stimuli: S (N = 6); B (N = 7); DOM (N = 7); SUB (N = 7); PRE (N = 6); POST (N = 6); after 45 min of stimulation (*P < 0.05). On the bottom-half, a depiction of the tilapia’s olfactory rosette (40x) and the apparatus for olfactory stimulation and electrophysiological recording of olfactory evoked potentials.