EFFECTS OF EXPOSURE TO PREDATORY CUES ON TERRITORIAL BEHAVIOR OF MALEFATHEAD MINNOWS

We conducted a laboratory study to determine if male fathead minnows, Pimephales promelas, altered their territorial behaviour associated wi th reproduction in response to combinations of visual and chemical cue s from north male: a brick (control), We introduced the following stim uli to a territorial male: a brick (control), fathead minnow alarm phe romone, a pike fed brook stickleback, Culea inconstans, or a pike fed fathead minnow. The territorial behaviour of males did not change when the control was added. Male minnows experiencing threat from pike fed stickleback significantly reduced the frequency at which they perform ed three territorial behaviours, but, within 12 h, had returned to pre -exposure activity levels. Male minnows subjected to alarm pheromone a lone and to pike fed fathead minnow significantly reduced their territ orial behaviour, abandoned their nests, and did not return to pre-expo sure levels of activity after 24 h. We suggest that because risk of pr edation triggers prolonged decreases in territorial defense, it may af fect competition between nesting males and female mate choice. We conc lude that fathead minnows can assess the severity of predatory threat and adjust their reproductive behaviour accordingly.