Issa Semona, Chaabani Safa, Asimakopoulos Alexandros G, Jaspers Veerle L B, Einum Sigurd
Department of Biology Centre for Biodiversity Dynamics Norwegian University of Science and Technology Trondheim Norway.
Norwegian Agriculture Agency Oslo Norway.
Ecol Evol. 2022 Apr 1;12(4):e8785. doi: 10.1002/ece3.8785. eCollection 2022 Apr.
The neurotransmitter dopamine has been shown to play an important role in modulating behavioral, morphological, and life history responses to food abundance. However, costs of expressing high dopamine levels remain poorly studied and are essential for understanding the evolution of the dopamine system. Negative maternal effects on offspring size from enhanced maternal dopamine levels have previously been documented in . Here, we tested whether this translates into fitness costs in terms of lower starvation resistance in offspring. We exposed mothers to aqueous dopamine (2.3 or 0 mg/L for the control) at two food levels ( vs. 30% ) and recorded a range of maternal life history traits. The longevity of their offspring was then quantified in the absence of food. In both control and dopamine treatments, mothers that experienced restricted food ration had lower somatic growth rates and higher age at maturation. Maternal food restriction also resulted in production of larger offspring that had a superior starvation resistance compared to groups. However, although dopamine exposed mothers produced smaller offspring than controls at restricted food ration, these smaller offspring survived longer under starvation. Hence, maternal dopamine exposure provided an improved offspring starvation resistance. We discuss the relative importance of proximate and ultimate causes for why . may not evolve toward higher endogenous dopamine levels despite the fitness benefits this appears to have.
神经递质多巴胺已被证明在调节对食物丰度的行为、形态和生活史反应中发挥重要作用。然而，高多巴胺水平表达的代价仍鲜有研究，而这对于理解多巴胺系统的进化至关重要。先前已有文献记载母体多巴胺水平升高对后代体型产生的负面影响。在此，我们测试了这是否会转化为后代较低的饥饿抵抗力方面的适合度代价。我们将处于两种食物水平（[具体数值1]对30%[具体数值2]）的母体暴露于多巴胺水溶液（对照组为2.3或0毫克/升）中，并记录了一系列母体生活史特征。然后在无食物的情况下对其后代的寿命进行量化。在对照和多巴胺处理中，经历食物定量受限的母体的体细胞生长率较低，成熟年龄较高。母体食物限制还导致产生的后代体型更大，与[具体数值1]组相比具有更强的饥饿抵抗力。然而，尽管在食物定量受限的情况下，暴露于多巴胺的母体产生的后代比对照组小，但这些较小的后代在饥饿状态下存活时间更长。因此，母体多巴胺暴露提高了后代的饥饿抵抗力。我们讨论了尽管多巴胺似乎具有适合度益处，但[具体内容]为何可能不会朝着更高的内源性多巴胺水平进化的近端和最终原因的相对重要性。
