PS 74-18 - Prey detection strategies of the Western lesser siren (Siren intermedia nettingi)

Friday, August 12, 2011
Exhibit Hall 3, Austin Convention Center
Daniel D. Goodding, Bradley T. Martin, Neil B. Ford and John S. Placyk, Biology, University of Texas at Tyler, Tyler, TX

The Western lesser siren, Siren intermedia nettingi, is a fully aquatic, paedomorphic salamander. This species is nocturnal and feeds on a variety of aquatic prey including crayfish, annelids, amphibian larvae and eggs, gastropods, and aquatic insects and their larvae. However, the foraging behavior of S. i. nettingi is poorly known. For our study, we examined sensory mediation of S. i. nettingi foraging behavior; specifically the response to chemical and visual stimuli.  We located holding tanks and test arenas in an environmental chamber in which we adjusted the temperature, lighting, and humidity to simulate conditions reflecting their active season in East Texas where they were captured. The test arena consisted of a rectangular, 78 L aquarium divided lengthwise by a centerline into two halves. Each half contained a single food chamber with either food (treatment) or no food (control). The chemical trials utilized opaque perforated food chambers, and the visual trials utilized clear, non-perforated food chambers. The trials lasted 60 minutes, and total time spent on each side was recorded. The data were analyzed using Wilcoxon signed-rank tests.


Our analyses indicated a significant difference between treatment groups, with an apparent preference for the chemical treatment. This suggests that sirens utilize chemical cues over visual cues when foraging. Our results are logical considering the fact that sirens have noticeably reduced eyes and are known to be nocturnal foragers. This study can contribute to the limited natural history knowledge of an amphibian species which is often found to be a top predator in aquatic systems in which it is found.

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