Hughes William O H, Boomsma Jacobus J
Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
Proc Natl Acad Sci U S A. 2008 Apr 1;105(13):5150-3. doi: 10.1073/pnas.0710262105. Epub 2008 Mar 13.
Social groups are vulnerable to cheating because the reproductive interests of group members are rarely identical. All cooperative systems are therefore predicted to involve a mix of cooperative and cheating genotypes, with the frequency of the latter being constrained by the suppressive abilities of the former. The most significant potential conflict in social insect colonies is over which individuals become reproductive queens rather than sterile workers. This reproductive division of labor is a defining characteristic of eusocial societies, but individual larvae will maximize their fitness by becoming queens whereas their nestmates will generally maximize fitness by forcing larvae to become workers. However, evolutionary constraints are thought to prevent cheating by removing genetic variation in caste propensity. Here, we show that one-fifth of leaf-cutting ant patrilines cheat their nestmates by biasing their larval development toward becoming queens rather than workers. Two distinct mechanisms appear to be involved, one most probably involving a general tendency to become a larger adult and the other relating specifically to the queen-worker developmental switch. Just as evolutionary theory predicts, these "royal" genotypes are rare both in the population and within individual colonies. The rarity of royal cheats is best explained as an evolutionary strategy to avoid suppression by cooperative genotypes, the efficiency of which is frequency-dependent. The results demonstrate that cheating can be widespread in even the most cooperative of societies and illustrate that identical principles govern social evolution in highly diverse systems.
社会群体容易受到欺骗行为的影响，因为群体成员的繁殖利益很少是一致的。因此，所有合作系统预计都包含合作型和欺骗型基因型的混合，后者的频率受到前者抑制能力的限制。社会性昆虫群落中最显著的潜在冲突在于哪些个体成为有繁殖能力的蚁后而非不育的工蚁。这种繁殖分工是真社会性社会的一个决定性特征，但单个幼虫会通过成为蚁后来最大化自身适应性，而其巢伴通常会通过迫使幼虫成为工蚁来最大化适应性。然而，进化限制被认为通过消除等级倾向的遗传变异来防止欺骗行为。在此，我们表明，五分之一的切叶蚁父系通过使幼虫发育偏向成为蚁后而非工蚁来欺骗它们的巢伴。似乎涉及两种不同的机制，一种很可能涉及成为体型更大成虫的一般倾向，另一种则特别与蚁后 - 工蚁发育转换相关。正如进化理论所预测的那样，这些“王室”基因型在种群和单个蚁群中都很罕见。王室欺骗者的罕见最好解释为一种进化策略，以避免被合作型基因型抑制，其效率取决于频率。结果表明，即使在最具合作性的社会中，欺骗行为也可能广泛存在，并说明相同的原则支配着高度多样化系统中的社会进化。
