四、鸟类的繁殖:求偶 TABLE 1 Effect of tail treatment of male swallows during one breeding season on fitness components during their following season Tail treatment Fitness component Control‖l (>010) Duration of pre-mating 26°(27 26°(20) 25°(18) 8567) (<001) Proportion having second clutches(96) edgings per male 73(16) 71°(28) 73(24) 40(19) (<001) 11(22) 9(21) 12(20) survival, proportion having second clutches)or means (1 s.d. )other fitness components). P values calculated from a G-test males having second clutches)or from a one-way analysis of variance(other fit rom each other if they have different superscripts(a and b)(P<0.05, Duncan le-range test). Sample sizes are number of nd, in parentheses, number of males originally manipulated Moller 1989. Nature 339: 13213 四、鸟类的繁殖：求偶 Moller 1989. Nature 339: 132