LACK OF RESPIRATORY COST OF TAIL AUTOTOMY IN THE LUNGLESS SALAMANDER, OEDIPINA-UNIFORMIS

Tail autotomy, an effective antipredator adaptation that enhances survival, may have attendant costs for the surviving prey. One potential cost not previously addressed in long-tailed, lungless salamanders that sacrifice the majority of their body mass by tail autotomy is the substantial reduction in respiratory surface area (RSA). We have tested the respiratory cost of tail autotomy in the bolitoglossine salamander, Oedipina uniformis, by (1) comparing resting and post-exercise oxygen consumption (VO2) in tailed and tailless Oedipina, and (2) comparing the tissue composition of bodies and tails. Metabolic studies indicated no significant effect of tail condition (pre- vs. post-autotomy) on resting VO2, the duration of exercise prior to exhaustion, or post-exercise VO2; aerobic recovery from exercise was also independent of tail condition. Tissue analyses (water and ash content, carbohydrate, lipid, and protein fractions) revealed that Oedipina bodies and tails are similar in composition (both high in muscle, low in lipid); thus the tail is largely a metabolically-homogeneous extension of the body. Our data suggest that tail autotomy in Oedipina does not alter the ratio between metabolically-active tissue mass and RSA, and that a respiratory cost of tail autotomy is of minor importance.