Costs associated with tail autotomy in an ambush foraging lizard, <i>Cordylus melanotus melanotus</i>

Abstract

Tail autotomy is a widespread method of escape among lizards and can be costly. Most studies on the effects of tail loss have focused on active foraging lizards, but few data exist for ambush foraging lizards. We investigated potential costs  associated with tail autotomy in an extreme ambush foraging cordylid lizard,  Cordylus melanotus melanotus. We induced tail autotomy in free ranging male Cordylus m. melanotus and measured potential shifts in behaviour (movements, foraging behaviour, time exposed and average distance to a potential refuge), and responses to an approaching human compared to marked individuals with complete tails. Tailed and tailless lizards behaved in a similar fashion for all measured variables although power tests could not rule out the possibility of falsely accepting the null hypothesis in some cases. We also measured locomotory performance  (maximum sprint speed) for tailed and tailless lizards in the lab. Locomotory  performance was also not compromised by tail loss. Finally, we measured the  energetic content of tails as a proportion of total energetic content using bomb calorimetry. The cost of tail autotomy was approximately 12 % of the total body energy (wet weight). Our results suggest that the major cost of tail loss in Cordylus m. melanotus is energetic.

Key words: tail loss, performance, antipredatory behaviour, tail energetic content, reptile.