Department of Entomology, Texas A&M University, College Station, TX, USA.
School of Biological Sciences, Illinois State University, Campus Box 4120, Normal, IL, 61790, USA.
Sci Rep. 2021 Jun 7;11(1):11925. doi: 10.1038/s41598-021-91317-w.
Locusts exhibit one of nature's most spectacular examples of complex phenotypic plasticity, in which changes in density cause solitary and cryptic individuals to transform into gregarious and conspicuous locusts forming large migrating swarms. We investigated how these coordinated alternative phenotypes might have evolved by studying the Central American locust and three closely related non-swarming grasshoppers in a comparative framework. By experimentally isolating and crowding during nymphal development, we induced density-dependent phenotypic plasticity and quantified the resulting behavioural, morphological, and molecular reaction norms. All four species exhibited clear plasticity, but the individual reaction norms varied among species and showed different magnitudes. Transcriptomic responses were species-specific, but density-responsive genes were functionally similar across species. There were modules of co-expressed genes that were highly correlated with plastic reaction norms, revealing a potential molecular basis of density-dependent phenotypic plasticity. These findings collectively highlight the importance of studying multiple reaction norms from a comparative perspective.
蝗虫表现出自然界中最壮观的复杂表型可塑性之一，其中密度的变化导致独居和隐匿的个体转变为群居和显眼的蝗虫，形成大型迁徙的蝗群。我们通过在比较框架内研究中美洲蝗虫和三种密切相关的非迁徙蚱蜢，研究了这些协调的替代表型如何进化。通过在若虫发育过程中进行实验隔离和拥挤，我们诱导了密度依赖性表型可塑性，并量化了由此产生的行为、形态和分子反应规范。所有四个物种都表现出明显的可塑性，但个体反应规范在物种间存在差异，且幅度不同。转录组反应是特定于物种的，但密度反应基因在物种间具有相似的功能。有一些共表达基因模块与塑性反应规范高度相关，揭示了密度依赖性表型可塑性的潜在分子基础。这些发现共同强调了从比较的角度研究多种反应规范的重要性。
