KAATZ, I.M.*; LOBEL, P.S.: Intra- and Interspecific Differences in Sound Production in the Neotropical Catfish Genus Corydoras (Callichthyidae)

The behavioral contexts of sound production and differences among sounds produced by callichthyid catfishes were characterized using captive populations observed in monospecific groups (10-15 adults per species). Disturbance is a context in which many families of catfishes produce sounds. Unlike other catfishes, few callichthyids produced sounds in the disturbance context (1% of tested individuals, n = 202; 17 species). Sound production in disturbance was a poorly ritualized display for non-reproductive individuals. All species and the majority of individuals engaged “spine locking” (gape-limitation) and “tail thrashing” (escape) defense mechanisms in disturbance. Intraspecific differences between reproductive and agonistic sounds were found. Pre-chase sounds of three species were low frequency (375-750 Hz frequency range) and statistically different from courtship sounds in total duration, pulse number, interpulse interval (two-way ANOVA, p = 0.0001) but not pulse duration. There were no interspecific differences between pre-chase, chase, or startle sounds. Interspecific differences were found between male courtship sounds for two species (C. paleatus and C. leopardus). Males produced sounds while displaying to females before egg fertilization. Courtship sounds were similar in frequency range (800 – 8,000 Hz) but significantly different in total duration, pulse number and interpulse interval (two-way ANOVA, p = 0.0001) but not pulse duration. Callichthyid catfishes produce specific sounds during defined behavioral contexts and the male courtship sound differed statistically between species. These results support the hypothesis that sound may play an important role in communication in these fishes.