Meeting Abstract

P1.218  Wednesday, Jan. 4  Thermal Preference and Habitat Choice in the Rough-Skinned Newt (Taricha granulosa COPENHAVER, P.E.*; POWERS, D.R.; George Fox University, Newberg, OR; George Fox University, Newberg, OR

For 10 months each year rough-skinned newts (Taricha granulosa) are confined to aquatic environments where temperatures vary (range: 5-25 °C). During this time newts must forage, undergo metamorphosis, and reproduce. To do this newts must behaviorally thermoregulate so that they can be active yet manage critical energy stores. In this study we measured behavior, SMR, and environmental conditions to assess how newts manage their thermal state and energy costs. Quadrat sampling was used to determine newt abundance and characterize water temperature for specific locations and depth. Newt body temperature (cloacal probe) was compared to environmental (water) temperature to verify temperature control. We measured SMR of aquatic-acclimated (AA) newts from 5-25 °C to assess basal energy costs. We compared SMR to SMR of terrestrial-acclimated (TA) newts to quantify the relative basal cost of aquatic existence. Newt abundance was higher in shallow regions (1-3m) with high vegetation (coverage >40%) and higher water temperatures (20-22 °C) than deeper (10-17 m), cooler (<10 °C) regions. Body temperature (20.6+2.0 °C) did not differ from average water temperature where newts were present (20.5+1.5 °C). SMR in AA newts was 1.1-1.5x lower than TA newts at all temperatures except at 5 °C where aquatic SMR was 1.8x higher. These data suggest that these newts are typical temperature conformers that select aquatic environments ~20 °C, which is likely within their preferred body temperature range. Their low SMR compared to TA newts might suggest metabolic adaptations favor the aquatic existence. The higher SMR observed at 5 °C in AA newts might help newts remain active during unpredictable cold spells that can occur during their reproductive period.