Lucas Christophe, Hughson Bryon N, Sokolowski Marla B
Commun Integr Biol. 2010 Jan;3(1):6-8. doi: 10.4161/cib.3.1.9723.
Reproductive division of labor is a defining characteristic of eusociality in insect societies. The task of reproduction is performed by the fertile males and queens of the colony, while the non-fertile female worker caste performs all other tasks related to colony upkeep, foraging and nest defence. Division of labor, or polyethism, within the worker caste is organized such that specific tasks are performed by discrete groups of individuals. Ordinarily, workers of one group will not participate in the tasks of other groups making the groups of workers behaviorally distinct. In some eusocial species, this has led to the evolution of a remarkable diversity of subcaste morphologies within the worker caste, and a division of labor amongst the subcastes. This caste polyethism is best represented in many species of ants where a smaller-bodied minor subcaste typically performs foraging duties while larger individuals of the major subcaste are tasked with nest defence. Recent work suggests that polyethism in the worker caste is influenced by an evolutionarily conserved, yet diversely regulated, gene called foraging (for), which encodes a cGMP-dependent protein kinase (PKG). Additionally, flexibility in the activity of this enzyme allows for workers from one task group to assist the workers of other task groups in times of need during the colony's life.In a recent article, Lucas and Sokolowski1 report that PKG mediates behavioral flexibility in the minor and major worker subcastes of the ant Pheidole pallidula. By changing the task-specific stimulus (a mealworm to induce foraging or alien intruders to induce defensive behavior) or pharmacologically manipulating PKG activity, they are able to alter the behavior of both subcastes. They also show differences in the spatial localization of the FOR protein in minor and major brains. Furthermore, manipulation of ppfor activity levels in the brain alters the behavior of both P. pallidula subcastes. The foraging gene is thus emerging as a major player in regulating the flexibility of responses to environmental change.
生殖分工是昆虫社会中真社会性的一个决定性特征。繁殖任务由蚁群中有繁殖能力的雄蚁和蚁后执行，而无繁殖能力的雌性工蚁阶层则承担与蚁群维护、觅食和巢穴防御相关的所有其他任务。工蚁阶层内部的分工，即多型行为，是有组织的，特定任务由不同的个体群体执行。通常，一个群体的工蚁不会参与其他群体的任务，使得工蚁群体在行为上有所不同。在一些真社会性物种中，这导致了工蚁阶层内亚阶层形态的显著多样性进化，以及亚阶层之间的分工。这种阶层多型行为在许多蚂蚁物种中表现得最为明显，体型较小的小型亚阶层通常承担觅食任务，而体型较大的大型亚阶层则负责巢穴防御。最近的研究表明，工蚁阶层的多型行为受一种名为觅食（for）的基因影响，该基因在进化上保守，但调控方式多样，它编码一种环鸟苷酸依赖性蛋白激酶（PKG）。此外，这种酶活性的灵活性使来自一个任务群体的工蚁能够在蚁群生活期间的需要时协助其他任务群体的工蚁。在最近的一篇文章中，卢卡斯和索科洛夫斯基报告说，PKG介导了苍白盲切叶蚁小型和大型工蚁亚阶层的行为灵活性。通过改变特定任务的刺激（一条黄粉虫以诱导觅食或外来入侵者以诱导防御行为）或通过药理学手段操纵PKG活性，他们能够改变两个亚阶层的行为。他们还展示了FOR蛋白在小型和大型工蚁大脑中的空间定位差异。此外，操纵大脑中ppfor的活性水平会改变苍白盲切叶蚁两个亚阶层的行为。因此，觅食基因正成为调节对环境变化反应灵活性的主要因素。
