Abstract：
In a much-cited 1964 paper entitled \"Reproductive efficiency in relation to colony size in hymenopterous societies,\" Charles Michener investigated the correlation between a colony\'s size and its reproductive efficiency - the ability of its adult females to produce reproductives, measured as per-capita output. Based on his analysis of published data from destructively sampled colonies in 18 species, he reported that in most of these species efficiency decreased with increasing colony size. His conclusion that efficiency is higher in smaller groups has since gained widespread acceptance. But it created a seeming paradox: how can natural selection maintain social behaviour when a female apparently enjoys her highest per-capita output by working alone? Here we treat Michener\'s pattern as a hypothesis and perform the first large-scale test of its prediction across the eusocial Hymenoptera. Because data on actual output of reproductives were not available for most species, Michener used various proxies, such as nest size, numbers of brood, or amounts of stored food. We show that for each of Michener\'s data sets the reported decline in per-capita productivity can be explained by factors other than decreasing efficiency, calling into question his conclusion that declining efficiency is the cause of the pattern. The most prominent cause of bias is the failure of the proxy to capture all forms of output in which the colony invests during the course of its ontogeny. Other biasing factors include seasonal effects and a variety of methodological flaws in the data sets he used. We then summarize the results of 215 data sets drawn from post-1964 studies of 80 species in 33 genera that better control for these factors. Of these, 163 data sets are included in two meta-analyses that statistically synthesize the available data on the relationship between colony size and efficiency, accounting for variable sample sizes and non-independence among the data sets. The overall effect, and those for most taxonomic subgroups, indicates no loss of efficiency with increasing colony size. Two exceptional taxa, the halictid bees and independent-founding paper wasps, show negative trends consistent with the Michener hypothesis in some species. We conclude that in most species, particularly those with large colony sizes, the hypothesis of decreasing efficiency with increasing colony size is not supported. Finally, we explore potential mechanisms through which the level of efficiency can decrease, be maintained, or even increase, as colonies increase in size.
摘要：
在1964年被广泛引用的一篇论文中，题为“膜翅目社会中生殖效率与菌落大小的关系”，“查尔斯·米切纳研究了殖民地的大小与其繁殖效率之间的相关性-成年雌性产生繁殖的能力，以人均产出衡量。根据他对18个物种破坏性采样菌落的公开数据的分析，他报告说，在大多数这些物种中，效率随着菌落大小的增加而降低。他的结论是，在较小的群体中效率更高，此后得到了广泛的接受。但是这似乎产生了一个悖论：当女性显然通过独自工作而享有最高的人均产出时，自然选择如何维持社会行为？在这里，我们将Michener的模式视为假设，并对其在整个社会性膜翅目中的预测进行了首次大规模测试。因为大多数物种的实际繁殖数据都没有，Michener使用了各种代理,比如巢的大小，育苗的数量，或储存的食物量。我们表明，对于Michener的每个数据集，报告的人均生产率下降可以用效率下降以外的其他因素来解释，质疑他的结论，即效率下降是这种模式的原因。偏见的最主要原因是代理人未能捕获殖民地在个体发育过程中投资的所有形式的产出。其他偏见因素包括季节性影响和他使用的数据集中的各种方法论缺陷。然后，我们总结了从1964年后对33属80种物种的研究中得出的215个数据集的结果，这些数据集可以更好地控制这些因素。其中,163个数据集包含在两个荟萃分析中，这些荟萃分析在统计学上综合了有关菌落大小与效率之间关系的可用数据，考虑可变样本量和数据集之间的非独立性。整体效果,以及大多数分类亚组的那些，表明随着菌落大小的增加，效率没有损失。两个特殊分类单元，halictid蜜蜂和独立的纸黄蜂，在某些物种中显示出与米切纳假说一致的负面趋势。我们得出结论，在大多数物种中，特别是那些具有大菌落大小的人，不支持效率随菌落大小增加而降低的假设。最后,我们探索效率水平下降的潜在机制，保持,甚至增加，随着菌落大小的增加。
