Regeneration of Mnemiopsis leidyi under different food quantities

Many marine invertebrates including ctenophores are capable of extensive body regeneration when injured. However, as for the invasive ctenophore Mnemiopsis leidyi, there is a constant subportion of individuals not undergoing whole body regeneration but forming functionally stable half-animals instead. Yet, the driving factors of this phenomenon have not been addressed so far. This study sheds new light on how differences in food availability affect self-repair choice and regeneration success in cydippid larvae of M. leidyi. As expected, high food availability favored whole-body regeneration. However, under low food conditions half-animals became the preferential self-repair mode. Remarkably, both regenerating and half-animals showed very similar survival chances under respective food quantities. As a consequence of impaired food uptake after injury, degeneration of the digestive system would often occur indicating limited energy storage capacities. Taken together, this indicates that half-animals may represent an alternative energy-saving trajectory which implies self-repair plasticity as an adaptive trade-off between high regeneration costs and low energy storage capacities. We conclude that self-repair plasticity could lead to higher population fitness of ctenophores under adverse conditions such as in ships' ballast water tanks which is postulated to be the major vector source for the species' spreading around the globe.

包括栉水母（ctenophores）在内的多种海洋无脊椎动物，在遭受损伤后均可实现大范围的身体再生。然而，入侵性栉水母物种莱氏拟翼管栉水母（Mnemiopsis leidyi）却始终存在一部分个体，不会进行全身再生，而是形成功能稳定的半体个体。目前，该现象的驱动因素仍未得到阐明。
本研究针对莱氏拟翼管栉水母的球栉幼体，探讨了食物可获得性差异对其自我修复选择与再生成功率的影响，为相关领域提供了全新视角。实验结果符合预期：充足的食物供给更有利于个体开展全身再生；而在食物匮乏条件下，形成半体个体则成为更优选的自我修复路径。值得注意的是，在各自对应的食物供给水平下，完成全身再生的个体与半体个体的存活概率极为相近。
由于损伤后个体的食物摄取能力受损，其消化系统常出现退化，这表明该物种的能量储存能力有限。
综合上述结果可知，半体个体或许代表了一种节能的替代发育路径，意味着自我修复可塑性是在高再生成本与低能量储存能力之间形成的适应性权衡。
我们的研究结论指出，在诸如船舶压载水舱这类不利环境中（该环境被认为是该物种全球扩散的主要传播媒介），自我修复可塑性可提升栉水母的种群适合度。