Caudal autotomy and regeneration in lizards

Abstract

Caudal autotomy, or the voluntary self-amputation of the tail, is an anti-predation strategy in lizards that depends on a complex array of environmental, individual, and species-specific characteristics. These factors affect both when and how often caudal autotomy is employed, as well as its overall rate of success. The potential costs of autotomy must be weighed against the benefits of this strategy. Many species have evolved specialized behavioral and physiological adaptations to minimize or compensate for any negative consequences. One of the most important steps following a successful autotomous escape involves regeneration of the lost limb. In some species, regeneration occurs rapidly; such swift regeneration illustrates the importance of an intact, functional tail in everyday experience. In lizards and other vertebrates, regeneration is a highly ordered process utilizing initial developmental programs as well as regeneration-specific mechanisms to produce the correct types and pattern of cells required to sufficiently restore the structure and function of the sacrificed tail. In this review, we discuss the behavioral and physiological features of self-amputation, with particular reference to the costs and benefits of autotomy and the basic mechanisms of regeneration. In the process, we identify how these behaviors could be used to explore the neural regulation of complex behavioral responses within a functional context.

Current Understanding on Tail Regeneration in Green Anoles (Anolis carolinensis)

“…The potential costs of autotomy must be weighed against the benefits of this strategy [24]. Therefore, the costs of self-amputation should be less than benefits or least to be merged.…”

“…Appendages may be lost when they have been envenomated as a method of removing the toxin or venom from the circulatory system [5]. To minimize or compensate the loss of tail shedding, lizards have evolved specialized behavioral and physiological adaptation practices i.e., regeneration of lost tails [24]. Furthermore, multiple advantages associated with self-amputation.…”

“…In green anoles, regeneration is a highly ordered process utilizing initial developmental programs as well as regeneration to produce the correct types and pattern of cells required to sufficiently restore the structures and functions of the sacrificed tail [24]. The genes responsible for regeneration of tails in Anolis carolinensis promote chondrogenesis, myogenesis, and neurogenesis [20].…”

Tail autotomy effects on the escape behavior of the lizard Gonatodes albogularis (Squamata: Sphaerodactylidae), from Córdoba, Colombia

“…However, tail loss has associated costs during the regeneration period in terms of reproduction and survival (Shine 1980;Fox and McCoy 2000;Webb 2006). For example, the absence of the tail in the first instance affects balance and all processes associated with locomotive performance (Vitt and Ohmart 1975;Ballinger et al 1979;Arnold 1988;Martín and Avery, 1998), stockpiling resources (Vitt et al 1977;McConnachie and Whiting 2003;Clause and Capaldi 2006), and social status (Martin and Salvador 1993;Salvador et al 1995;Niewiarowski et al 1997;Fox and McCoy 2000). In addition, caudal autonomy makes individuals more vulnerable to predation (Dial and Fitzpatrick 1984;Daniels et al 1986;Downes and Shine 2001;Cooper et al 2004;Medger et al 2008).…”

Physiological and immunocytochemical evidence that glutamatergic neurotransmission is involved in the activation of arm autotomy in the featherstarAntedon mediterranea(Echinodermata: Crinoidea)

“…Surprisingly little is known of the neural basis of tail autotomy in reptiles and other vertebrates (Clause and Capaldi, 2006). There are, on the other hand, detailed accounts of the anatomy and electrophysiology of the nervous circuitry associated with the autotomy mechanisms of decapod crustaceans (McVean, 1974;Findlay and McVean, 1977), a nudibranch (Bickell-Page, 1989) and a hydromedusa (Bickell-Page and Mackie, 1991).…”