在现代生态系统中，雀形目鸟类（Passeriformes）被认为是黄蜂拟态的主要选择者。然而，在早渐新世的欧洲，雀形目鸟类却非常罕见。那么，在那个时期，是什么因素促使了这种高度精准的拟态形成呢？研究人员推测，选择最早已知的高度精准黄蜂拟态者的可能是 Coraciimorphae 和 Apodiformes ...

Royalty-free licenses let you pay once to use copyrighted images and video clips in personal and commercial projects on an ongoing basis without requiring additional payments each time you use that ...

These S&P 500 ETFs all track the index, but there are some small differences that may impact which one you buy. Many, or all, of the products featured on this page are from our advertising ...

A tentative agreement has been signed and will be presented to the members once the translation is available. Click through to the full article to see some highlights. SP Executive Newsletter # 3 ...