News Animals

An all-female wasp is rapidly spreading across North America’s elms

The elm zigzag sawfly is spreading fast. Now it targets trees planted to replace diseased elms

A close-up photo shows a black sawfly perched on the edge of a green leaf, with its wings folded along its body.

Originally from East Asia, the elm zigzag sawfly has expanded its range across North America at a rate that alarms biologists

jobangles/iNaturalist

By Ute Eberle

She’s less than a centimeter long, produces only daughters and is conquering the continent without a single male.