TY - JOUR TI - Triiodothyronine (T3) action on aquatic locomotor behavior during metamorphosis of the bullfrog Rana catesbeiana AU - Fernández-Mongil, Marisabel AU - Venza, CeliaJ. AU - Rivera, Amelia AU - Lasalde-Dominicci, JoséA. AU - Burggren, Warren AU - Rojas, LegierV. T2 - The International Journal of Developmental Biology AB - Thyroid hormones - particularly triiodothyronine, T3 - play a critical role in the morphological transformations comprising metamorphosis in larval bullfrogs (Rana catesbeiana). Traditional staging criteria for anuran larvae incompletely distinguish physiological and behavioral changes during growth. We therefore first developed a new parameter to describe larval growth, the developmental index (DI), which is simply the ratio between the tail length of the larva and its head diameter. Using the DI we were able to identify two distinct populations classifying the larvae during growth along a continuous linear scale with a cutoff value of DI at 2.8. Classification based on the DI, used in this study, proved an effective complement to existing classifications based on developmental staging into pre- or pro-metamorphic stages. Exposure to T3 in the water induced a rapid (beginning within 5 min) and significant decrease (~20-40%) in locomotor activity, measured as total distance traversed and velocity. The largest decrease occurred in more developed larvae (DI PY - 2009 DO - 10.1387/ijdb.072307mf VL - 53 IS - 1 SP - 101 EP - 108 J2 - Int. J. Dev. Biol. LA - en SN - 0214-6282 SN - 1696-3547 UR - https://ijdb.ehu.eus/article/072307mf Y2 - 2024/11/21/22:37:01 ER -