An all-female wasp is rapidly spreading across North America’s elms
She’s less than a centimeter long, produces only daughters and is conquering the continent without a single male. Meet the elm zigzag sawfly, named for the delicate zigzag patterns it carves into elm tree leaves. Despite its name, the elm zigzag sawfly (Aproceros leucopoda) is not a fly; it is a type of wasp first…
