BACKGROUND Social insects (ants, bees, wasps and termites) are considered as prime examples of altruism in which individuals (workers) forego their own reproduction to help other individuals reproduce. Such a behaviour is favoured by natural selection because the workers rear close kin and in doing so enhance their inclusive fitness. RESULTS Here I show, however, that this does not generally apply to termite workers which are scarcely investigated. In the basal drywood termite Cryptotermes secundus the 'workers', which form the large majority of a colony, did not stay to raise relatives. There is no brood caring behaviour and they do not engage in costly help. They are large immature offspring that develop into either winged (dispersing) or unwinged (replacement) reproductives and the probability that they did so was unaffected by the number of brood in the nest as a brood addition experiment showed. CONCLUSION Thus, in contrast to general perception where termite workers are considered equivalent to workers in Hymenoptera, the 'large immatures' of C. secundus did not behave as workers that help in raising younger siblings. This apparently is not necessary as the colony lives inside its food. These results, which are likely to be typical for wood-dwelling termites, open the possibility that large complex group living can evolve without altruistic helping and that costly altruistic helping by workers in termites evolved only as a second step.

中文翻译：

---

枯木白蚁的工人不工作。

背景技术社会昆虫（蚂蚁，蜜蜂，黄蜂和白蚁）被认为是利他主义的主要例子，其中个人（工人）放弃自己的繁殖以帮助其他个体繁殖。自然选择有利于这种行为，因为工人养成近亲，从而提高了他们的包容性。结果然而，我在这里表明，这通常不适用于很少进行调查的白蚁工人。在基干木材白蚁隐孢子中，构成殖民地大部分的“工人”没有留下来抚养亲戚。没有育儿行为，他们也不参与昂贵的帮助。它们是大型的未成熟后代，可以发育成有翅的（分散的）或无翅的（替代的）繁殖，并且如添加育雏实验所示，它们繁殖的可能性不受巢中育雏数量的影响。结论因此，与通常认为白蚁工人等同于膜翅目的工人的一般认识相反，C。secundus的“大型不成熟个体”并不表现为有助于抚养年轻兄弟姐妹的工人。由于殖民地生活在其食物中，因此这显然不是必需的。这些结果可能是居住白蚁的典型结果，打开了大型复杂的群体生活可以在没有利他主义帮助的情况下发展的可能性，而白蚁工人付出的昂贵的利他主义帮助仅是作为第二步进化的可能性。