The Effects of Feeding Behavior and Canopy Closure on Morphology and Development of Larval Bufo terrestris

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Feeding behavior in tadpoles (rasping vs. filtering) could potentially result in variation in chondrocranial morphology due to the influence of muscular forces on the shape of primary cartilage. In order to test the effect of feeding behavior on morphology, Southern Toad tadpoles (Bufo terrestris) were reared in laboratory conditions and subjected to two dietary treatments: a rasping treatment where tadpoles were fed algae grown on ceramic tiles, and a filtering treatment where tadpoles were fed a suspension of crushed tadpole food, and phytoplankton (Chlorella sp.). Food resources of the aquatic habitats exploited by larval anurans can be influenced by the amount of available sunlight, whereby, open canopy ponds typically experience more primary production than detrital based closed canopy ponds. Furthermore, given the increased primary productivity and greater abundance of phytoplankton it is likely that filtering feeding behavior is more common in open canopy ponds, whereas, rasping feeding is necessitated by closed canopy ponds. Likewise, canopy closure may affect water temperature which is of substantial importance to anuran development. In order to test the effect of canopy closure on morphology and development of larval B. terrestris outdoor mesocosms were constructed and assigned to one of three shade treatments (full sunlight, 30% shade, 70% shade). Preliminary data suggests that the larval period of tadpoles raised in 70% shade treatments was substantially longer than for those raised in full sunlight and 30% shade treatments. Measurements of overall size (total length, body length, etc.) will reveal possible effects of shade treatment on these characteristics. Additionally, the effect of diet and shade treatments on chondrocranial morphology will be presented.


Society for Integrative and Comparative Biology Annual Meeting (SICB)


San Antonio, TX