Fischer Klaus, Zwaan Bas J, Brakefield Paul M
Institute of Evolutionary and Ecological Sciences, Section Evolutionary Biology, Leiden University, P.O. Box 9516, 2300, RA Leiden, The Netherlands.
Oecologia. 2002 May;131(3):375-379. doi: 10.1007/s00442-002-0913-9. Epub 2002 May 1.
Although arthropod egg size is an evolutionarily and ecologically significant trait, there is still a poor understanding of the specific factors determining it. For butterflies there is evidence from an interspecific comparison that egg size is related to adult size, suggesting a morphological constraint. Using laboratory populations of the tropical butterfly Bicyclus anynana, we show that larger eggs produce larger hatchlings, and that there is considerable intra-populational variation in egg size. However, the correlation between egg size and female size is weak and explains only 1% of the variation found within a population; even development time is a slightly better predictor for egg size than female size. We conclude that there is no evidence that body size imposes a constraint on the evolution of egg size within butterfly populations. However, populations that have diverged in body size under artificial selection show correlated responses in egg size. Thus, correlations between body size and egg size may represent an emergent property, visible only when a large range of differences in body size is considered.
尽管节肢动物的卵大小是一个具有进化和生态意义的性状，但对于决定它的具体因素仍知之甚少。对于蝴蝶，种间比较的证据表明卵大小与成虫大小有关，这暗示了一种形态学限制。利用热带蝴蝶小弄蝶（Bicyclus anynana）的实验室种群，我们发现较大的卵会孵出较大的幼虫，并且种群内卵大小存在相当大的差异。然而，卵大小与雌蝶大小之间的相关性较弱，仅解释了种群内发现的变异的1%；甚至发育时间对卵大小的预测能力都比雌蝶大小稍强。我们得出结论，没有证据表明体型对蝴蝶种群内卵大小的进化施加了限制。然而，在人工选择下体型发生分化的种群在卵大小上表现出相关反应。因此，体型与卵大小之间的相关性可能是一种仅在考虑到体型的大范围差异时才可见的涌现特性。
