The processes and mechanisms of organ-number evolution : a comprehensive case study for insect genital structures

器官的数量在动物分类群中是不同的。然而，由于它们的稀缺性，我们对器官数量进化变化的原因和方式了解甚少。本研究对昆虫生殖器官数量的进化变化进行了全面的资料收集。因此，估计至少在7个昆虫目中发生了雄性性腺孔数量的进化变化。除了分支、退化和融合过程外，“功能转移”已被发现是器官数量进化的一种新型机制。

The number of organs varies among animal taxa. However, due to their scarcity, we have a poor understanding of why and how the number of organs evolutionarily changes. In the present study, a comprehensive information gathering has conducted about evolutionary changes in the numbers of insect reproductive/genital components. As a result, evolutionary changes in the number of male gonopore have been estimated to be occurred in at least seven insect orders. In addition to branching, degeneration, and fusion processes, "transfer of function" has been detected as a novel type of mechanisms for the evolution of organ number.