4 research outputs found
Sounds Modulate Males’ Aggressiveness in a Cichlid Fish
International audienceAcoustic signals are produced in many fish species during agonistic or courtship interactions. A way to test the biological role of these sounds is the use of acoustic playback experiments. However, sounds are usually associated with visual displays and playback experiments performed in fish so far, often failed to match acoustic and visual stimuli. To avoid this mismatch issue, we experimentally separated or coupled visual and acoustic channels to test the role of sounds produced during male–male aggressive interactions in a cichlid fish, Metriaclima zebra. Results show that aggressive behaviour is based on visual stimuli and that acoustic signals alone never trigger aggression. Furthermore, the association between visual and acoustic channels lowers the level of aggressiveness found when fish can only interact visually. This suggests that acoustic signals used during a dispute may complement visual displays to modulate males’ behaviour by reducing their aggressiveness and the risk of escalated fights
The role of agonistic sounds in male nest defence in the Painted Goby Pomatoschistus pictus
Animals often vocalize during territorial challenges as acoustic signals may
indicate motivation and fighting ability and contribute to reduce aggressive
escalation. Here, we tested the function of agonistic sounds in territorial
defence in the painted goby. Pomatoschistus pictus, a small vocal marine
fish that defends nests during the breeding season. We first measured the
number of times a male approached, avoided, explored, entered and
exited two unattended nests associated with either conspecific agonistic
sounds or a control: silence or white noise. Acoustic stimuli were played
back when the male approached a nest. In a second experimental set, we
added visual stimuli, consisting of a conspecific male in a small confinement
aquarium near each nest. Even though we found no effect of the
visual stimuli, the sound playbacks induced similar effects in both experimental
conditions. In the sound vs. silence treatment, we found that
when males approached a nest, the playback of conspecific sounds usually
triggered avoidance. However, this behaviour did not last as in longer periods
males visited nests associated with agonistic sounds more often than
silent ones. When the control was white noise, we found no significant
effect of the playback treatment in male behaviour. Although we cannot
exclude the possibility that other sounds may dissuade nest occupation,
our results suggest that agonistic sounds act as territorial intrusion deterrents
but are insufficient to prevent nest intrusion on their own. Further
studies are needed to test the significance of sound production rate,
spectral content and temporal patterns to deter territorial intrusion in fish