Sex ratios in bumble bees
Sex ratios in bumble bees
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DOI：
10.1098/rstb.1997.0179
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发表时间：
1997-12-29
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影响因子：
--
通讯作者：
Bourke, AFG
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文献类型：
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作者：
Bourke, AFG
7种大黄蜂（Bombus） 11个种群雌蜂投入比例中位数为0.32（范围为0.07 ~ 0.64）。相比之下，相关属的两种无工蜂群居寄生虫的性别分配偏向于雌性，其原因尚不清楚。Bombus的雄性偏向性分配与Trivers & Hare对社会膜翅目昆虫的性别比例模型的预测相矛盾，该模型认为蜂王控制下的种群性投资比应为0.5(1:1)，工蜂控制下的种群性投资比应为0.75(3:1)（假设单一，一次交配，近亲繁殖的蜂王和无繁殖能力的工蜂）。Bombus中的男性偏见似乎既不是人为的，也不纯粹是共生性别比例扭曲的结果。根据对Trivers-Hare模型的修正，Bombus的工人男性生产水平不足以解释观察到的男性偏见水平。也没有证据表明男性偏见是由本地资源竞争（相关雌性竞争资源）或本地配偶增强（相关雄性合作获得配偶）引起的。Bulmer提出了预测膜翅目昆虫年度社会中原雄制（雄性先于雌性产生）性选择的模型，并作为结果（给定一些参数值），雄性偏向性分配。大黄蜂符合布尔默模型的假设，而且是雌雄同体的。因此，这些模型代表了目前对蜜蜂的雄性偏向性投资比率的最佳解释。这一结论表明，雌雄生殖的相对时间对社会膜翅目昆虫的性别分配有很大的影响。
The median proportion of investment in females among 11 populations of seven bumble bee (Bombus) species was 0.32 (range 0.07-0.64). By contrast, two species of workerless social parasites in the related genus Psithyrus had female-biased sex allocation, the reasons for which remain unclear. Male-biased sex allocation in Bombus contradicts the predictions of Trivers & Hare's sex ratio model for the social Hymenoptera, which are that the population sex investment ratio should be 0.5 (1:1) under queen control and 0.75 (3:1 females:males) under worker control (assuming single, once-mated, outbred queens and non-reproductive workers). Male bias in Bombus does not appear to be either an artefact, or purely the result of symbiotic sex ratio distorters. According to modifications of the Trivers-Hare model, the level of worker male production in Bombus is insufficient to account for observed levels of male bias. There is also no evidence that male bias arises from either local resource competition (related females compete for resources) or local mate enhancement (related males cooperate in securing mates). Bulmer presented models predicting sexual selection for protandry (males are produced before females) in annual social Hymenoptera and, as a consequence (given some parameter values), male-biased sex allocation. Bumble bees fit the assumptions of Bulmer's models and are protandrous. These models therefore represent the best current explanation for the bees' male-biased sex investment ratios. This conclusion suggests that the relative timing of the production of the sexes strongly influences sex allocation in the social Hymenoptera.