Publication Date

8-2023

Advisor(s) - Committee Chair

Michael Smith, Steve Huskey, Philip Lienesch

Degree Program

Department of Biology

Degree Type

Master of Science

Abstract

Sound production is a means of communication among many fish species. In fishes, sound is produced through various mechanisms, but in the family Loricariidae, known as armored suckermouth catfishes, sound is produced primarily through pectoral fin spine stridulation. Previous experiments have described the sounds produced and shown the mechanism of sound production in two species of loricariid catfishes, Pterygoplichthys gibbiceps and Otocinclus affinis, but the functional significance of loricariid sounds is still unknown. To address this question, I examined the behavioral responses of Pterygoplichthys pardalis and Otocinclus vittatus to conspecific calls. Individual fish (N=10 for P. pardalis) or groups of 20 fish (N=4 groups for O. vittatus) were acclimated to an aquarium for at least 24 h. Individual P. pardalis were video recorded for 2 minutes with no sound, plus another 2 minutes with a playback of either a 500 Hz tone control or conspecific call through an underwater speaker. In contrast, O. vittatus was video recorded for 5 minutes with no sound, with an additional 5 minutes of either conspecific call or 500 Hz tone stimuli. This procedure was repeated for each individual or group using either a 500 Hz tone and conspecific call for playback so that each individual or group received both stimuli. I hypothesized that P. pardalis would avoid, while O. vittatus would be attracted to, the conspecific sound-emitting speaker, respectively. The rationale for this hypothesis is that P. pardalis produces calls when it is under duress, so it may be an alarm call, while O. vittatus produces calls spontaneously in large groups of fish, suggesting it may be a cohesion call or involved in other intraspecific interactions. P. pardalis showed an increased activity level to conspecific sound compared to the 500 Hz tone, although movement in general was minimal, while O. vittatus exhibited a short-lived response to conspecific calls by moving toward the speaker with the sound source. Since both species showed a minimal behavioral change to sound playbacks, more research is needed to better understand the function of sound production in loricariid catfishes.

Disciplines

Behavior and Ethology | Biodiversity | Biology | Ecology and Evolutionary Biology | Integrative Biology | Life Sciences | Physiology

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