Yellow jackets (Vespula) are aggressive, social wasps and significant predators of the European honey bee (Apis mellifera). They possess powerful mandibles and a sting that can be used repeatedly, unlike the honey bee’s barbed stinger. This predation is devastating, especially to smaller or less vigorous colonies.
The Predatory Drive
Yellow jacket attacks are motivated by the nutritional needs of their colony. Adult yellow jackets primarily sustain themselves on carbohydrates, such as nectar, ripe fruit, or honeydew. However, the developing larvae require a high-protein diet for proper growth. Honey bees, insects, and carrion provide this protein source. Worker yellow jackets capture and process the prey, conditioning it to feed their young. A honey bee colony represents a large, concentrated source of protein readily available to the wasps.
Attack Techniques and Hive Entry
Yellow jacket foragers often scout the area around a hive, sometimes drawn by the scent of honey or bee pheromones. A common tactic involves ambushing individual honey bee foragers returning to the entrance. The yellow jacket quickly subdues the bee, often by biting off its head or wings. Once immobilized, the wasp dismembers the body and flies back to its nest with small, protein-rich pieces.
The most significant threat is coordinated attacks aimed at breaching hive defenses. Their goal is to reach the honey bee brood (larvae and pupae), which is the most concentrated, high-quality protein source available.
Peak Threat Season and Colony Impact
Yellow jacket predation is highly seasonal, peaking sharply in late summer and early fall, typically from August through October. This period coincides with the yellow jacket colony reaching its maximum size, sometimes housing thousands of workers, leading to a massive demand for protein. Simultaneously, natural nectar flows often decline, creating food scarcity and increasing pressure on the wasps to find alternative sources.
A sustained attack places immense stress on the honey bee colony, forcing guard bees to defend the entrance instead of foraging. Small or weakened colonies are vulnerable and may be overwhelmed, leading to the destruction of comb, loss of the queen, and ultimately, hive collapse or abandonment.
Protecting Honey Bee Colonies
Beekeepers can implement several strategies to help colonies defend against yellow jackets.
Physical Defenses
A highly effective physical defense is reducing the hive entrance size using specialized hardware like entrance reducers or robbing screens. This minimizes the area guard bees must defend, making it much harder for the larger wasps to push their way inside.
Trapping
Trapping is a proactive measure, particularly effective in the spring to catch new queens, preventing the establishment of large colonies nearby. Later in the season, traps baited with protein or a chemical lure, such as heptyl butyrate, can reduce worker populations. These traps should be placed at least twenty feet away from the hive to prevent them from inadvertently drawing more yellow jackets toward the bees.