In the spring and early summer, wasps are attracted to protein contained in pet food, garbage scraps and exposed compost piles. During the cooler late summer and fall months, wasps seek out sweet foods, such as rotten tree fruits, open soda cans and fruit juices.
Wasps remember where food sources exist and may return even after the source is removed. When wasps are swatted or squashed, they release a chemical pheromone that attracts and excites nearby wasps who then exhibit aggressive, threatening behavior. Brightly colored or flowered clothing also attracts wasps, as do highly scented or fruity perfumes. Wasp stings are prone to infection due to high bacterial levels obtained from fecal matter while hunting.