Grether Gregory F
Animal Behavior Group, Division of Environmental Studies, University of California, Davis, California, 95616.
Evolution. 1996 Oct;50(5):1939-1948. doi: 10.1111/j.1558-5646.1996.tb03581.x.
I review methodological problems that can lead to false evidence for selection on secondary sexual characters and present a study of selection in rubyspot damselflies (Hetaerina americana) that avoids these pitfalls. Male rubyspots have a large red spot on each wing that grows to a terminal size after sexual maturity. Selection gradient analyses revealed evidence for positive sexual and survival selection on both terminal wing spot size and body size. Phenotype manipulations confirmed that wing spot size was subject to direct sexual selection, but showed that the positive slope of survival on wing spot size was an indirect effect of selection on unmeasured traits. This study provides the strongest evidence yet for sexual selection on coloration in Odonata, but also provides clear examples of why phenotypic selection statistics must be calculated and interpreted cautiously.
我回顾了可能导致关于第二性征选择的错误证据的方法学问题，并展示了一项对红宝石豆娘（美洲赫氏豆娘）选择的研究，该研究避免了这些陷阱。雄性红宝石豆娘的每只翅膀上都有一个大的红色斑点，性成熟后会生长到最终大小。选择梯度分析揭示了在翅膀末端斑点大小和体型上存在正向性选择和生存选择的证据。表型操纵证实翅膀斑点大小受到直接性选择，但表明翅膀斑点大小与生存之间的正斜率是对未测量性状选择的间接影响。这项研究为蜻蜓目动物颜色的性选择提供了迄今为止最有力的证据，但也清楚地举例说明了为什么必须谨慎计算和解释表型选择统计数据。
