Hornets are apex insect predators, and the simple answer to whether they kill wasps is yes. As members of the genus Vespa, hornets frequently prey on other social wasps, including yellow jackets, as a primary food source. This predatory relationship is a natural dynamic within many ecosystems. The interaction is driven by the colony’s constant need for protein to sustain its developing young, leading hornets to actively seek out smaller wasp colonies and individual foragers.
Defining Hornets, Wasps, and Yellow Jackets
The terms “hornet,” “wasp,” and “yellow jacket” are often used interchangeably, but they represent distinct groups within the insect family Vespidae. All hornets are technically wasps, but they belong exclusively to the genus Vespa and are generally the largest members of the family. True hornets, such as the European hornet (Vespa crabro), are characterized by a robust body and are typically marked with shades of reddish-brown, yellow, and black.
Yellow jackets belong mainly to the genera Vespula and Dolichovespula. They are noticeably smaller than true hornets, usually featuring a more distinct, vibrant black and yellow striped pattern. The bald-faced hornet, despite its common name, is actually a species of yellow jacket (Dolichovespula maculata), distinguished by its black and white coloration.
Paper wasps, belonging to the genus Polistes, represent a third group commonly confused with the others. These wasps have a characteristically slender body with long legs that trail visibly while in flight. Paper wasps build single-layer, exposed nests made of a papery pulp, contrasting with the multi-layered, enclosed paper nests built by many hornets and yellow jackets.
The Nature of Hornet Predation on Wasps
The primary motivation for a hornet to kill a wasp is the nutritional needs of its developing brood, not aggression. Hornet larvae require a diet rich in protein to grow and reach maturity. Adult worker hornets are the dedicated hunters, capturing insects, including smaller wasps and yellow jackets, to provide this essential nutrient source.
Once a hornet captures a smaller wasp, it chews the prey into a soft, protein-rich paste called a bolus. This bolus is transported back to the nest and fed directly to the larvae via trophallaxis. This exchange is a fundamental aspect of hornet social life, converting the protein into a usable form for the entire colony.
Adult hornets require mostly carbohydrates for their high-energy foraging flights and cannot effectively digest solid protein. The larvae, however, possess the necessary enzymes to break down the protein bolus. In return, the larvae secrete a nutrient-rich liquid containing free amino acids and carbohydrates, which the adult workers consume to fuel their activities. This reciprocal feeding loop between the larvae and the foraging adults creates a biological dependency that drives the continuous need for protein-based prey.
Hornets often hunt individually, ambushing foraging wasps or yellow jackets, but they may also engage in organized attacks. Some species, like the European hornet, will raid the exposed nests of paper wasps (Polistes) to capture the vulnerable larvae directly. These attacks are focused on harvesting the protein-heavy brood of the smaller wasp colony as a strategic act of resource acquisition. The constant predatory pressure from hornets acts as a natural control on populations of other social wasps, maintaining ecological balance.
The Impact of Invasive Hornet Species
The predatory behavior of hornets becomes a significant ecological concern when non-native, invasive species are introduced. The Asian Giant Hornet (Vespa mandarinia) and the Yellow-legged Hornet (Vespa velutina) are two examples that pose a disproportionate threat to native insect populations. These species are highly efficient predators that have evolved specialized tactics to overwhelm the defenses of social insect colonies.
The Asian Giant Hornet, the world’s largest hornet, employs a multi-phase attack on honey bee colonies. The initial “hunting phase” involves a lone scout capturing individual foragers near the nest entrance. This is followed by the devastating “slaughter phase,” where a group of up to 50 hornets launches a coordinated mass attack.
During the slaughter phase, the hornets systematically kill every adult defender, often using their mandibles to decapitate them, until the colony’s defense is eliminated. These attackers can decimate a colony of 25,000 to 30,000 honey bees in just a few hours. Once the adults are killed, the hornets enter the “occupation phase,” harvesting the protein-rich pupae and larvae to feed their own colony.
The Yellow-legged Hornet (Vespa velutina) uses a different but effective strategy known as “bee-hawking.” Workers hover stationary in front of a hive entrance, snatching individual honey bees as they leave or return. Although this is not a mass-slaughter event, the persistent removal of foragers severely weakens the prey colony over time. This predatory pressure represents a substantial threat to both native wasp populations and managed honey bee colonies.