Both wasp species appear slim with clearly skinnier midsection and sport cylinder-shaped legs. The chitinous exoskeleton is smooth, reflective and hairless.
Yellow jackets are approximately one-half inch in length and smaller than hornets. Their black-and-yellow-striped pattern is their trademark.
Hornets are larger than yellow jackets, at roughly three-fourth of an inch long, with the European giant hornet measuring up to 1 inch in length. Their colors range between black, off-white and brown.
Hornets and yellow jackets are able to sting more than once.
Yellow jackets are a greater culprit when it comes to stings than hornets. They attack whenever they feel threatened, no matter if they are alone or with a swarm. Refrain from injuring a yellow jacket near a nest, as it will expel a pheromone that will call and raise the aggressiveness of the swarm. Their aggression is at the peak in late summer and early fall.
Hornets most commonly only attack when their nest is threatened. Prepare to be chased by a greater number of aggressive insects, as they will defend their home. The sting of the bald-faced hornet is known to be so strong that it can even penetrate clothing.
Yellow jacket nests can be outside and on the inside of buildings, wherever small crevices allow access to a hidden location. The nests are made from a light-brown substance much like paper. They also build nests underground, using old rodent habitats.
Hornets always build their nests outside, preferably high off the ground in tree branches or near the roofs of houses, away from most predators. Their nests are made from a papery material, which is gray in color. They often look like a football or a tear drop turned upside down.
During early summer the diet of yellow jackets is protein-oriented, much like that of hornets. Later in summer they start getting into soda cans, sugary dishes and trash cans pursuing any sweet source of food.
Hornets are helpful in insect control because they prefer an exclusive diet of larvae and other pests.