When two organisms typically do not interbreed with one another, they are considered different species. But what are the reproductive barriers that isolate one population from another? Hear the ...

A new study of interbreeding between two species of howler monkeys in Mexico is yielding insights into the forces that drive the evolution of new species. A new University of Michigan study of ...

Slate takes a break from endless political analysis to tackle a biological question: Can humans have sex with other animals and produce offspring? The answer: "Probably not." Um, "probably"? Oh dear.

How species form and what keeps them distinct from each other, even though they can interbreed, is a key question in evolution. Researchers have recently identified genes in three closely related ...

"A new species develops if a population which has become geographically isolated from its parental species acquires during this period of isolation characters which promote or guarantee reproductive ...

Few data are available on the effectiveness of reproductive isolating mechanisms in externally fertilizing taxa. I investigated patterns of conspecific and heterospecific fertilization among three ...

Aradus cinnamomeus Panzer, the pine bark bug, is a pest of young Scots pines which exhibits a two-year pattern of periodicity in most parts of Europe. The alternate-year populations live almost ...