Meeting Abstract
Intraoral food processing refers to any form of mechanical reduction of food within the mouth prior to swallowing. Processing mechanisms are known for all major vertebrate clades, but the form and function of systems used to crush, grind, or puncture food items differ substantially between as well as within major clades. In most vertebrates, mechanisms of intraoral processing display flexibility and can be adjusted to demands of different environmental conditions or food types. Recently, we described a peculiar processing mechanism in newts and showed that they use cyclic loop-motions of the tongue to rasp prey against the palatal dentition. However, it is not known if newts can modulate their processing behavior in response to different conditions. Newts provide interesting models for studying functional modulation in response to different conditions due to their unique and flexible lifestyle: Newts seasonally change between aquatic and terrestrial habitats and consume a wide range of food types. Here, we test the effects of (i) the medium where feeding occurs (water/air) and (ii) food type (maggot, earthworm, cricket) on the processing behavior in the newt Triturus carnifex. Using x-ray high-speed recordings, anatomical investigations and behavioral analyses, we demonstrate that newts show little change in food processing between aquatic and terrestrial feeding. However, they adjust the number of processing cycles to different prey types. For example, while maggots are processed extensively, earthworm pieces are swallowed nearly unreduced. We conclude that sensory feedback such as smell, taste and material properties induce flexible processing responses, while the medium where feeding occurs appears to have less of an effect.
