Allocation costs of regeneration: tail regeneration constrains body growth under low food availability in juvenile lizards

Irene Fernández-Rodríguez,Florentino Braña

doi:10.1007/s00442-021-05084-6

Irene Fernández-Rodríguez, Florentino Braña

Open Access

https://doi.org/10.1007/s00442-021-05084-6

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Journal: Oecologia	Publication Date: Dec 14, 2021
Citations: 1	License type: open-access

Affiliation: University of Oviedo, Biodiversity Research Institute

Abstract

The balance of energy allocated to development and growth of different body compartments may incur allocation conflicts and can thereby entail physiological and evolutionary consequences. Regeneration after autotomy restores the functionality lost after shedding a body part but requires a strong energy investment that may trade-off with other processes, like reproduction or growth. Caudal autotomy is a widespread antipredator strategy in lizards, but regeneration may provoke decreased growth rates in juveniles that could have subsequent consequences. Here, we assessed the growth of intact and regenerating hatchling wall lizards (Podarcis muralis) exposed to different food regimens. Regenerating juveniles presented slightly but significantly lower body growth rates than individuals with intact tails when facing low food availability, but there were no differences when food was supplied ad libitum. Regenerating individuals fed ad libitum increased their ingestion rates compared to intact ones during the period of greatest tail growth, which also reveals a cost of tail regeneration. When resources were scarce, hatchlings invested more in tail regeneration in relation to body growth, rather than delay regeneration to give priority to body growth. We propose that, in juvenile lizards, regeneration could be prioritized even at the expense of body growth to restore the functionality of the lost tail, likely increasing survivorship and the probability to reach reproductive maturity. Our study indicates that food availability is a key factor for the occurrence of trade-offs between regeneration and other growth processes, so that environmental conditions would be determinant for the severity of the costs of regeneration.

Highlights

Animal life histories exhibit an outstanding diversity, modulated by decisions about the timing of certain events and the allocation of the assimilated energy (Roff 1992; Reznick 2017)
Tailed and tailless lizards of both ad libitum and restricted food experiments did not differ in SVL at hatching, but tailless lizards’ body mass at birth was slightly lower in both experiments (Table 1)
Experimental studies have given less attention to the investment of energy and materials associated to regeneration following autotomy and the potential subsequent costs for growth or reproduction

Summary

Introduction

Animal life histories exhibit an outstanding diversity, modulated by decisions about the timing of certain events and the allocation of the assimilated energy (Roff 1992; Reznick 2017). This study gives insight into the evolution of allocation trade-offs that may occur during regeneration. It sheds light on the on the interpretations of previous studies that addressed this question. Some animals have the ability to self-mutilate a body part as a reflex response when they are threatened, which is called “autotomy” (Maginnis 2006). Self-mutilation, often followed by the regeneration of the lost parts to restore the organism’s functionality, evolved independently several times in different animal lineages, both invertebrates and vertebrates (Goss 1969; Arnold 1988; Bely and Nyberg 2010; Clause and Capaldi 2006; Lin et al 2017). Caudal autotomy is a frequent antipredator strategy in lizards, occurring in 13 out of 20 families of saurians

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