Data from: Sperm use economy of honeybee (Apis mellifera) queens

The queens of eusocial ants, bees, and wasps only mate during a very brief period early in life to acquire and store a lifetime supply of sperm. As sperm cannot be replenished, queens have to be highly economic when using stored sperm to fertilize eggs, especially in species with large and long-lived colonies. However, queen fertility has not been studied in detail, so that we have little understanding of how economic sperm use is in different species, and whether queens are able to influence their sperm use. This is surprising given that sperm use is a key factor of eusocial life, as it determines the fecundity and longevity of queens and therefore colony fitness. We quantified the number of sperm that honeybee (Apis mellifera) queens use to fertilize eggs. We examined sperm use in naturally mated queens of different ages and in queens artificially inseminated with different volumes of semen. We found that queens are remarkably efficient and only use a median of 2 sperm per egg fertilization, with decreasing sperm use in older queens. The number of sperm in storage was always a significant predictor for the number of sperm used per fertilization, indicating that queens use a constant ratio of spermathecal fluid relative to total spermathecal volume of 2.364 × 10−6 to fertilize eggs. This allowed us to calculate a lifetime fecundity for honeybee queens of around 1,500,000 fertilized eggs. Our data provide the first empirical evidence that honeybee queens do not manipulate sperm use, and fertilization failures in worker-destined eggs are therefore honest signals that workers can use to time queen replacement, which is crucial for colony performance and fitness.真社会性（eusocial）蚂蚁、蜜蜂与胡蜂的蜂后仅在生命早期极短的窗口期内完成交配，以获取并储存终生所需的精子。由于精子无法补充，蜂后在使用储存的精子受精卵子时必须极为经济高效，尤其是在拥有大型长寿社群的物种中。然而，目前针对蜂后生殖力的研究尚不够深入，我们对不同物种中精子使用的经济性，以及蜂后能否调控自身的精子使用模式，都知之甚少。考虑到精子使用是真社会性生存的关键因素——它决定了蜂后的繁殖力与寿命，进而影响社群适合度——这一现状着实令人意外。 本研究量化了西方蜜蜂（Apis mellifera）蜂后用于受精卵子的精子数量。我们分别考察了不同日龄的自然交配蜂后，以及经人工授精使用不同剂量精液的蜂后的精子使用情况。 研究发现，蜂后的精子使用效率极高，每枚受精卵子的精子使用量中位数为2；且随着蜂后日龄增长，精子使用量呈下降趋势。储存的精子总数始终能显著预测单次受精所用的精子数量，表明蜂后取用的受精囊液（spermathecal fluid）体积占总受精囊体积的恒定比例为2.364×10⁻⁶。借此我们可推算出西方蜜蜂蜂后的终生产卵量约为150万枚受精卵子。 本研究数据首次提供了实证证据，证明西方蜜蜂蜂后并不会调控精子使用模式，因此工蜂所遭遇的预定发育为工蜂的卵子受精失败事件，实为可靠的诚实信号——工蜂可借此判断时机开展蜂后更替，这对社群的表现与适合度至关重要。