Schwab Daniel B, Moczek Armin P
Department of Biology, Indiana University, Bloomington, IN 47405, USA
Department of Biology, Indiana University, Bloomington, IN 47405, USA.
Proc Biol Sci. 2014 Oct 22;281(1793). doi: 10.1098/rspb.2014.1625.
Resource allocation trade-offs arise when developing organs are in competition for a limited pool of resources to sustain growth and differentiation. Such competition may constrain the maximal size to which structures can grow and may force a situation in which the evolutionary elaboration of one structure may only be possible at the expense of another. However, recent studies have called into question both the consistency and evolutionary importance of resource allocation trade-offs. This study focuses on a well-described trade-off between the horns and eyes of Onthophagus beetles and assesses the degree to which it is influenced by genetic, developmental and ecological conditions. Contrary to expectations, we observed that trade-off signatures (i) were mostly absent within natural populations, (ii) mostly failed to match naturally evolved divergences in horn investment among populations, (iii) were subject to differential changes in F1 populations derived from divergent field populations and (iv) remained largely unaffected by developmental genetic manipulations of horn investment. Collectively, our results demonstrate that populations subject to different ecological conditions exhibit different patterns of, and differential plasticity in, resource allocation. Further, variation in ecological conditions, rather than canalized developmental mechanisms, may determine whether and to what degree morphological structures engage in resource allocation trade-offs.
当正在发育的器官为获取维持生长和分化所需的有限资源库而相互竞争时，就会出现资源分配的权衡取舍。这种竞争可能会限制结构能够生长到的最大尺寸，并可能导致一种情况，即一个结构的进化细化可能只能以牺牲另一个结构为代价。然而，最近的研究对资源分配权衡取舍的一致性和进化重要性提出了质疑。本研究聚焦于粪金龟角与眼睛之间一种描述详尽的权衡取舍，并评估其受遗传、发育和生态条件影响的程度。与预期相反，我们观察到权衡取舍特征：（i）在自然种群中大多不存在；（ii）大多未能与种群间角投资的自然进化差异相匹配；（iii）在源自不同野外种群的F1种群中会发生不同变化；（iv）在很大程度上不受角投资的发育基因操纵影响。总体而言，我们的结果表明，处于不同生态条件下的种群在资源分配方面表现出不同模式和不同可塑性。此外，生态条件的差异，而非固定的发育机制，可能决定形态结构是否以及在何种程度上参与资源分配的权衡取舍。
