Yellow jackets are predatory social wasps, recognized by distinct black and yellow striped patterns. Unlike hairy bees, they have a noticeably segmented body with a small “waist.” Found worldwide, with about 16 species in the U.S., they build paper-like nests from chewed cellulose, often underground, in hollow logs, or sheltered areas like tree cavities and building eaves.
Understanding Yellow Jacket Behavior
Yellow jackets are generally not aggressive unless they perceive a threat, particularly to their nest. Their definition of a “threat” can be broad, leading to highly defensive behavior. As social insects living in large colonies, workers fiercely protect their nest.
Common triggers for aggressive stinging include vibrations, such as from lawnmowers, or approaching too close to their nest. Swatting at a yellow jacket also provokes them, as quick movements are interpreted as a direct attack. When injured or killed, a yellow jacket can release alarm pheromones, signaling danger and drawing more wasps to defend against the perceived threat.
Yellow jackets are predatory wasps, capable of multiple stings due to smooth, barbless stingers, unlike honeybees. They also bite for grip before stinging. Their diet varies: in spring and early summer, they hunt insects like caterpillars and flies to feed larvae. By late summer and fall, as natural food sources diminish, they scavenge for sugary substances and proteins, often drawn to human food and drinks. This dietary shift and increased population density lead to more frequent encounters and heightened aggression during these seasons.
Preventing Stings
To minimize sting risk, understand yellow jacket attractants. They are drawn to strong scents; avoid perfumes, colognes, and scented body products outdoors. They are also attracted to sweet foods and beverages; keep food and drinks covered outside and dispose of waste properly in sealed containers.
Wearing light-colored clothing can be beneficial, as yellow jackets are attracted to dark or bright colors. When working in the yard or overgrown areas, wear long-sleeved shirts, long pants, and closed-toe shoes for a physical barrier. Regularly inspect outdoor areas for potential nesting sites, such as ground holes or sheltered spots under eaves, to avoid accidental disturbances. If a nest is identified, contact a pest control professional for safe removal, as self-removal can provoke a mass attack.
Responding to a Sting
If stung, move away immediately to avoid further stings, as yellow jackets can sting repeatedly and are drawn by alarm pheromones. Clean the sting site thoroughly with soap and water. Apply a cold compress or ice pack to the affected area to reduce pain and swelling.
Over-the-counter antihistamines can alleviate itching and swelling, while pain relievers like acetaminophen or ibuprofen can manage discomfort. Watch for signs of a severe allergic reaction (anaphylaxis), including wheezing, difficulty breathing, throat tightness, hives, dizziness, nausea, or vomiting. If these symptoms appear, seek emergency medical attention immediately, and if available, use an epinephrine auto-injector (EpiPen).