Norman V C, Pamminger T, Hughes W O H
School of Life Sciences, University of Sussex, Brighton, East Sussex BN1 9QG UK.
Insectes Soc. 2017;64(1):75-85. doi: 10.1007/s00040-016-0513-z. Epub 2016 Sep 15.
The flexibility of organisms to respond plastically to their environment is fundamental to their fitness and evolutionary success. Social insects provide some of the most impressive examples of plasticity, with individuals exhibiting behavioral and sometimes morphological adaptations for their specific roles in the colony, such as large soldiers for nest defense. However, with the exception of the honey bee model organism, there has been little investigation of the nature and effects of environmental stimuli thought to instigate alternative phenotypes in social insects. Here, we investigate the effect of repeated threat disturbance over a prolonged (17 month) period on both behavioral and morphological phenotypes, using phenotypically plastic leaf-cutting ants () as a model system. We found a rapid impact of threat disturbance on the behavioral phenotype of individuals within threat-disturbed colonies becoming more aggressive, threat responsive, and phototactic within as little as 2 weeks. We found no effect of threat disturbance on morphological phenotypes, potentially, because constraints such as resource limitation outweighed the benefit for colonies of producing larger individuals. The results suggest that plasticity in behavioral phenotypes can enable insect societies to respond to threats even when constraints prevent alteration of morphological phenotypes.
生物体对环境做出可塑性反应的灵活性是其适应性和进化成功的基础。群居昆虫提供了一些最令人印象深刻的可塑性例子，个体表现出行为上的，有时是形态上的适应，以适应它们在群体中的特定角色，比如负责巢穴防御的大型兵蚁。然而，除了蜜蜂这种模式生物外，对于那些被认为能促使群居昆虫产生替代表型的环境刺激的性质和影响，几乎没有进行过研究。在这里，我们以具有表型可塑性的切叶蚁为模型系统，研究了在长达17个月的时间里反复受到威胁干扰对行为和形态表型的影响。我们发现，威胁干扰对受威胁干扰群体中个体的行为表型有迅速的影响，在短短2周内，这些个体就变得更具攻击性、对威胁更敏感且具有趋光性。我们发现威胁干扰对形态表型没有影响，这可能是因为诸如资源限制等制约因素超过了群体产生更大个体所带来的益处。结果表明，即使在制约因素阻止形态表型改变时，行为表型的可塑性也能使昆虫群体对威胁做出反应。
