Yellow Jackets are the ones that bother us the most during outdoor events, as they like to snack on the same foods we do. Sweet pop is a favorite. One trick you might try is to actually feed them starting two or three days ahead of the event in an area well away from the picnic. They get used to finding an easy meal and it will take quite a while before zeroing in on the meal you have for the picnic goers. Yellow jackets can sting repeatedly. The next most likely to be ready to sting are the paper nest building wasps and hornets. They will leave you alone if you leave them alone, but will certainly sting if provoked. Any of these insects will protect themselves when threatened and do so in great numbers.
Wasps, Hornets and Yellow jackets start a new nest every year and are not necessarily going to nest in the same spot year after year, while if you have a great spot you can have repeat nest building. These insects will typically die off in the fall with enough overwintering adults to start again the following year. Adults overwinter singularly in cracks and crevices and in naturally occurring spots in nature.
Lessor known stinging insects include Carpenter bees (only the female when disturbed), found tunneling in wood and the Giant Cicada Killer that only really stings its prey.When these stinging insects pose a real threat to humans, control measures are warranted. Treating a nest can be very dangerous, so be well prepared and have a buddy system in place! If you just have found the nest and have not been bothered all summer, let nature take its course. All of these stinging insects are important to the insect world, our ecosystem and our food chain. If you are finding stinging insects, check the condition of the caulking on the home. Those that have strong allergic reactions to a sting should talk with the family doctor about potential treatments.