Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2200 Copenhagen, Denmark.
Am Nat. 2013 Feb;181(2):161-70. doi: 10.1086/668828. Epub 2013 Jan 10.
The ultimate causes of honest signaling remain a subject of debate, with questions remaining over the relative importance of costs and constraints. Signal costs may make dishonesty prohibitively expensive, while genetic constraints could make it impossible. We investigated honest signaling using full-sib analysis and parent-offspring regression in the ant Lasius niger, in which queens produce a cuticular hydrocarbon-based pheromone that signals fertility and inhibits worker reproduction and aggression. We found multiple lines of evidence that cuticular hydrocarbon production is genetically correlated with oogenesis and that the queen pheromone 3-methylhentriacontane and other 3-methylalkanes have strong genetic links with fertility relative to other cuticular hydrocarbons. These genetic correlations may maintain honesty in the face of directional selection on signaling and explain the putatively widespread use of cuticular hydrocarbons in fertility signaling across the social insects. We also found evidence for a positive genetic correlation for fertility between the castes; that is, the most fertile queens produced especially fertile workers. These results highlight that intercaste genetic correlations could constrain the evolution of queen-worker dimorphism, such that worker reproduction may sometimes reflect a nonadaptive "caste load" rather than positively selected cheating.
诚实信号的最终原因仍然存在争议，信号成本和约束的相对重要性问题仍然存在。信号成本可能使不诚实变得过于昂贵，而遗传约束可能使其变得不可能。我们使用黑腹土蜂的全同胞分析和亲子回归来研究诚实信号，在这种蚂蚁中，女王产生一种基于表皮碳氢化合物的信息素，它可以传递生育能力，并抑制工蚁的繁殖和攻击。我们发现了多种证据表明，表皮碳氢化合物的产生与卵子发生具有遗传相关性，并且与其他表皮碳氢化合物相比，女王信息素 3-甲基三十烷和其他 3-甲基链烷烃与生育能力具有很强的遗传联系。这些遗传相关性可能在信号的定向选择面前保持诚实，并解释了在社会性昆虫中广泛使用表皮碳氢化合物进行生育能力信号传递的现象。我们还发现了在等级之间生育能力存在正遗传相关性的证据；也就是说，最肥沃的女王产生了特别肥沃的工蚁。这些结果突出表明，种间遗传相关性可能限制了女王-工蚁二态性的进化，使得工蚁的繁殖有时可能反映出非适应性的“等级负担”，而不是被积极选择的欺骗。
