Wasp
Wasps first appeared in the fossil record in the Jurassic, and diversified into many surviving superfamilies by the Cretaceous. They are a successful and diverse group of insects with tens of thousands of described species; wasps have spread to all parts of the world except for the polar regions. The largest social wasp is the Asian giant hornet, at up to in length; among the largest solitary wasps is a group of species known as tarantula hawks, along with the giant scoliid of Indonesia ("Megascolia procer"). The smallest wasps are solitary chalcid wasps in the family Mymaridae, including the world's smallest known insect, with a body length of only , and the smallest known flying insect, only long.
Dryocosmus kuriphilus
Dryocosmus kuriphilus is a species of gall wasp known by the common names chestnut gall wasp, Oriental chestnut gall wasp, and Asian chestnut gall wasp. It is native to China and it is known in many other parts of the world, particularly the Northern Hemisphere, as an introduced species and an invasive horticultural pest. It attacks many species of chestnut (genus "Castanea"), including most cultivated varieties. It is considered the world's worst pest of chestnuts.