Meeting Abstract
Corydoras catfishes produce sounds with microscopic ridges on the base of the pectoral spine. Sounds are a series of broadband frequency pulses greater in duration in courtship than agonism or disturbance for aquarium populations. Sound production is rare for nonbreeding fish, linking the significance of sounds to social and mate interactions for breeding-conditioned individuals. Startle sounds are rare and similar to courtship sounds. Three hypotheses were tested to determine the behavioral significance of courtship and startle sounds: 1) incidental sound hypothesis: incidental by-product of male fin displays during female courtship movements; 2) physiological priming hypothesis: female stimulation or mating synchronization during spawning; or 3) communication hypothesis: species recognition, females assessing male quality or social signals. Courtship sound pulse number correlated with duration: A) C. paleatus n = 56, r = 0.91, F(1,54)= 277.1, p<0.001; B) C. leopardus n = 56, r = 0.90, F(1,54) = 225.7, p<0.001; and C) C. aeneus n = 103, r= 0.82, F(1,101) = 205.3, p < 0.001. Startle sound pulse number correlated with duration (n = 31, r =0.82, F(1, 29)=22.5, p<0.00005) for a pooled group of species (C. aeneus, n = 14; C. leopardus, n = 9; C. sychri, n = 3; C. reticulatus, n = 4; C. paleatus, n = 1). Courtship associated sounds differ among species suggesting male display. Startle sounds were spectrographically similar across species suggesting an alarm signal to conspecifics or congeners. The presence of temporally patterned sounds in specific behavioral contexts supports the communication hypothesis.
