Hawkins Bradford A, Lawton John H
NERC Centre for Population Biology, Imperial College, Silwood Park, SL5 7PY, Ascot, Berks, UK.
Oecologia. 1995 Apr;102(1):31-36. doi: 10.1007/BF00333307.
We tested for the existence of latitudinal gradients in the body sizes of butterflies in North America, Europe, Australia and the Afrotropics. We initially compared body sizes (measured as male forewing length) of all butterflies found in 5° latitudinal bands in each region, and then evaluated the relationship between body size and latitude statistically using the latitudinal midpoint of each species' distribution. Trends were examined for species in all butterfly families together and for each family separately. We found that gradients in body sizes were inconsistent in different geographical regions and butterfly families; in some cases species were larger towards the tropics, in some they were smaller, and in other cases there were no relationships. Most of the gradients, when they existed, reflected between-family effects arising from changes in the relative numbers of species in each family across regions. We conclude that general ecological explanations for geographical trends in butterfly body sizes are inappropriate, and gradients largely reflect historical patterns of speciation within and between taxa in each biogeographical realm. Thus, the robustness of body size gradients found in other insect groups should be confirmed in future studies by including more than one geographical region whenever possible.
我们对北美洲、欧洲、澳大利亚和热带非洲地区蝴蝶的体型是否存在纬度梯度进行了测试。我们首先比较了每个地区5°纬度带内发现的所有蝴蝶的体型（以雄性前翅长度衡量），然后使用每个物种分布的纬度中点对体型与纬度之间的关系进行统计评估。对所有蝴蝶科的物种以及每个科分别进行了趋势研究。我们发现，不同地理区域和蝴蝶科的体型梯度并不一致；在某些情况下，物种在热带地区体型更大，在某些情况下体型更小，而在其他情况下则不存在关联。大多数梯度（如果存在的话）反映了各地区每个科物种相对数量变化所产生的科间效应。我们得出结论，对蝴蝶体型地理趋势的一般生态学解释并不恰当，梯度在很大程度上反映了每个生物地理区域内和不同分类单元之间物种形成的历史模式。因此，其他昆虫类群中发现的体型梯度的稳健性应在未来研究中尽可能纳入多个地理区域加以证实。
