文獻來源: Raffinger E, Ladich F. 2009. Acoustic threat displays and agonistic behaviour in the red-finned loach Yasuhikotakia modesta. Journal of Ethology 27(2): 239-247.
Agonistic behaviour and the significance of acoustic threat displays were investigated in juvenile red-finned loaches, Yasuhikotakia modesta. This species produced two different vocalizations during agonistic encounters—clicks and butting sounds. Clicks were produced at some distance from the opponent whereas butting sounds were emitted when one fish touched the other with its mouth. This occurred primarily during circling. Both sound types were short broadband signals with the main energies concentrated at about 230 Hz, but clicks were longer in duration and lower in sound level. Agonistic behaviour usually started when one fish approached the other, spread its fins and produced clicks (threat displays), which was followed by parallel displaying, circling and chasing. All fish approached a mirror quickly and displayed aggressively in a parallel position. The number and duration of the threat displays in front of the mirror image were significantly elevated compared with control experiments (rear of the mirror). When playing back click trains in the presence of a mirror image, loaches vocalized significantly less often than during the silent periods, whereas the amount of lateral displaying remained similar. These data indicate that agonistic sounds reduced acoustic displays in red-finned loaches.