SEX-INVESTMENT RATIOS IN ANTS - HAS FEMALE BIAS BEEN SYSTEMATICALLY OVERESTIMATED
SEX-INVESTMENT RATIOS IN ANTS - HAS FEMALE BIAS BEEN SYSTEMATICALLY OVERESTIMATED
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DOI：
10.1086/284933
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发表时间：
1989-04-01
影响因子：
2.9
通讯作者：
BOOMSMA, JJ
中科院分区：
文献类型：
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作者：
BOOMSMA, JJ
Trivers 和 Hare (1976) 以及 Nonacs (1986a) 声称，单性蚂蚁的性投资比例平均为 3:1，这种说法被认为是站不住脚的，因为 (1) 雌性与雄性干重成本比率存在偏差，这是由于随着性二态性的增加，呼吸和脂肪积累速率的差异越来越大； (2) 小样本估计的性别比数值存在偏差。雌雄 (f/m) 性别比 (S) 对个体干重比 (D) 和样本量 (N) 的部分回归似乎始终存在于单雌蚂蚁和多雌蚂蚁的数据集中，尽管仅对于单雌蚂蚁而言显着如此。这些关系主要被解释为方法论假象，但也讨论了可能的生物学解释。然而，替代解释并没有得到很好的数据支持和/或仅适用于部分数据集。假设干重成本比仅对无性二态性的物种无偏，推导了一个近似公式，将干重 f/m 成本比 (D) 转换为近似能量 f/m 成本比 (C)。发现公式 C = D0.7 可以对 Lasius niger 的个体干重比和能量成本比之间的差异进行可靠的定量预测，这是早期根据经验估计的（Boomsma 和 Isaaks 1985）。对假设的人工产物进行调整后，单雌蚂蚁的几何平均投资比率估计为 1.82:1，有利于雌蚁，与 1:1 和 3:1 显着不同。 The adjusted pattern is consistent with the hypothesis that workers control the sex-allocation process throughout monogynous ants, but in a context of variable degrees of relatedness asymmetry because of the frequent occurrence of multiple mating and worker reproduction.
The claim by Trivers and Hare (1976) and Nonacs (1986a) that the ratio of sexual investment in monogynous ants is as much female-biased as 3:1 on the average is argued to be untenable because of (1) bias in the gyne-to-male dry-weight cost ratios, as a result of increasingly diverging rates of respiration and fat accumulation with increasing sexual dimorphism; and (2) bias in the numerical sex ratios estimated from small samples. Partial regressions of the numerical gyne-to-male (f/m) sex ratio (S) on the individual dry-weight ratio (D) and sample size (N) appeared to be consistently present in the data sets for monogynous and polygynous ants, although significantly so only for the monogynous ants. These relationships were primarily interpreted as methodological artifacts, but possible biological explanations are also discussed. The alternative explanations, however, are less well supported by data and/or apply to only parts of the data set. Under the assumption that dry-weight cost ratios are unbiased only for species without sexual dimorphism, an approximate formula was derived to transfer dry-weight f/m cost ratios (D) into approximately energetic f/m cost ratios (C). The formula C = D0.7 was found to give a reliable quantitative prediction of the difference between the individual dry-weight ratio and the energetic-cost ratio in Lasius niger, which was earlier estimated empirically (Boomsma and Isaaks 1985). After adjustment for the assumed artifacts, the geometric-mean investment ratio across monogynous ants was estimated to be 1.82:1 in favor of gynes and to differ significantly from both 1:1 and 3:1. The adjusted pattern is consistent with the hypothesis that workers control the sex-allocation process throughout monogynous ants, but in a context of variable degrees of relatedness asymmetry because of the frequent occurrence of multiple mating and worker reproduction.