Department of Organisms and Systems Biology (Zoology), University of Oviedo, 33071, Oviedo, Spain.
Biodiversity Research Institute (IMIB, UO/CSIC/PA), University of Oviedo, Mieres, Spain.
Oecologia. 2022 Apr;198(4):853-864. doi: 10.1007/s00442-021-05084-6. Epub 2021 Dec 14.
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.
能量在不同身体部位的发育和生长之间的分配平衡可能会产生分配冲突，并因此带来生理和进化上的后果。自割后的再生恢复了失去身体部位后的功能，但需要大量的能量投入，这可能会与其他过程（如繁殖或生长）产生权衡。尾部自割是蜥蜴中广泛存在的一种防御策略，但再生可能会导致幼体生长速度下降，从而产生后续影响。在这里，我们评估了暴露在不同食物条件下的完整和再生孵化期壁蜥（Podarcis muralis）的生长情况。当食物供应不足时，再生的幼体会出现轻微但显著低于有完整尾巴个体的身体生长速度，但当食物供应充足时，两者之间没有差异。当食物供应充足时，再生个体在尾巴生长最快的时期增加了摄食量，这也表明了尾巴再生的代价。当资源匮乏时，幼体在与身体生长相关的尾巴再生上投入更多，而不是延迟再生以优先考虑身体生长。我们提出，在幼年蜥蜴中，即使牺牲身体生长，也会优先考虑再生，以恢复失去的尾巴的功能，这可能会提高存活率和达到生殖成熟的概率。我们的研究表明，食物的可获得性是再生和其他生长过程之间权衡的关键因素，因此环境条件将决定再生代价的严重程度。
