Yellow jackets are known predators of bees, and this predatory interaction represents a significant biological conflict within the ecosystem. These social wasps target bees, most commonly the European honey bee, as a source of protein to sustain their growing colonies. This dynamic shifts the context of the interaction from peaceful coexistence to direct predation, particularly around managed apiaries where food resources are concentrated.
Identifying the Combatants
The insects involved in this conflict are often confused, but they belong to two distinct groups: the fuzzy, pollen-collecting bees (Apidae) and the smooth, predatory wasps known as yellow jackets (Vespula species). A honey bee exhibits a rounded, densely hairy body, which is adapted for collecting and transporting pollen, and typically has muted yellow and black or amber coloration. In contrast, the yellow jacket is sleek and slender, with a defined, thin waist and a shiny, hairless exoskeleton featuring bright, bold yellow and black stripes.
Behaviorally, the honey bee is primarily a pollinator, focusing on nectar and pollen, and only stings when its hive is directly threatened, often dying afterward. Yellow jackets are aggressive scavengers and predators, able to sting multiple times, and they actively hunt other insects to feed their young. While yellow jackets are sometimes mistakenly called hornets (Vespa species), they are smaller. The primary targets are often the European honey bee workers, although native solitary bees can also fall victim to the yellow jacket’s opportunistic hunting.
The Predatory Mechanism
Yellow jackets are primarily motivated by the need for protein, which is an indispensable nutrient for their developing larvae back at the nest. Worker wasps hunt live insects, including bees, to fulfill this dietary requirement for the next generation of their colony. The larvae, in turn, secrete a sugar-rich substance that the adult yellow jackets consume for their own energy, creating a direct dependency on the protein source.
The hunt often begins near the bee colony entrance or on foraging routes where bees are distracted or isolated. A yellow jacket will locate its prey and then attack using its powerful mandibles to bite, or its stinger to paralyze or kill the bee. Once the bee is subdued, the yellow jacket begins a process of dismemberment, often on the spot, to prepare the carcass for transport.
The wasp focuses on the bee’s thorax, which is the most protein-rich section containing the flight muscles. The yellow jacket meticulously severs the head, abdomen, and wings, leaving them behind to fly the nutrient-dense thorax back to its nest. Multiple yellow jackets may be drawn to a single dead bee, showcasing their scavenging nature. This highly efficient processing ensures the maximum amount of protein is delivered to the yellow jacket brood.
Threat to Bee Colonies
The threat from yellow jackets intensifies in the late summer and early autumn when their colonies reach their maximum population size. During this period, natural insect prey populations often decline, and nectar sources become scarce, increasing the wasps’ predatory focus on the concentrated resources of a bee colony. These sustained attacks are often referred to as “robbing,” where yellow jackets not only predate adult bees but also attempt to steal honey and consume the bee brood (eggs, larvae, and pupae).
An invasion places stress on the bee colony, as the loss of adult worker bees depletes the foraging force and weakens the hive’s defensive capabilities. If the yellow jacket pressure is relentless, especially against a small or already weak colony, the wasps can overwhelm the guard bees at the entrance. Once inside, they can destroy the wax comb and consume the honey, sometimes leading to the complete collapse or abandonment of the bee colony.
Honey bees have evolved defensive behaviors to counter this threat. They vigorously guard the hive entrance and reduce the size of the opening to create a bottleneck. They also engage in a coordinated group defense known as ‘balling,’ where a mass of bees surrounds a single wasp and vibrates their flight muscles to generate heat, effectively cooking and killing the intruder. The yellow jacket’s ability to sting repeatedly gives it an advantage in one-on-one combat, making a unified colony defense necessary to survive an assault.