There are over 100,000 species of wasps worldwide. The most common species is the paper wasp. Hornets and yellowjackets are also classified as vespid wasps, but some people mistake them for bees. Wasps can nest in a wide range of areas and prefer places like attics, sheds, chimneys, and eaves. One of the biggest threats from wasps is their ability to defend their colony. They will attack and sting when disturbed or their nests are threatened. Unlike bees, they can sting several times without causing harm to themselves. Their stings can lead to serious complications if attacked by a swarm or you have an allergic reaction to their venom. They are most aggressive around nest sites and present the greatest danger when they nest near an entrance to a home or office.
Wasps release pheromones that signal other wasps in the colony to attack when they feel threatened. They can call the entire swarm for help. Hundreds of people die each year from allergic reactions to wasp venom. Hornets are also a problem in beekeeping communities because they can feed on bees and can eliminate a whole colony in a matter of hours.
For more information: Wasp Control