Hornets are large social wasps of the genus Vespa, distinguished from yellow jackets by their stockier build and typically more muted coloration. They operate in highly organized colonies that require resources for growth throughout the season. Understanding the substances and environments that draw these insects near is the first step in minimizing unwanted encounters. Hornets are primarily attracted by two needs: a changing seasonal diet and the requirement for sheltered nesting locations.
Dietary Triggers: Sugars and Proteins
The nutritional requirements of a hornet colony shift significantly throughout the year, which dictates their foraging targets and explains their seasonal presence around human food sources. Early in the season, adult worker hornets focus on gathering protein to feed the developing brood. The young larvae require amino acids for growth, obtaining them from a diet of chewed insects, carrion, and scavenged meat scraps.
Adult hornets bring protein-rich morsels like dead insects or fish back to the nest for the larvae. The larvae then secrete a carbohydrate-rich substance that the adults consume, creating a reciprocal feeding relationship known as trophallaxis. This dynamic means that any exposed meat, fish, or pet food outdoors in the spring and early summer can act as a powerful attractant for foraging workers.
The colony’s dietary focus changes dramatically in late summer and autumn as the larval population declines and new queens and males are produced. With fewer larvae supplying sugary secretions, adult hornets must forage for their own energy source, which is pure carbohydrate. They are strongly drawn to high-sugar items like tree sap, fermenting or overripe fruit, spillage from soda cans, and sugary alcoholic beverages outdoors. This late-season search for energy is when hornets are most frequently encountered by people enjoying outdoor activities.
Nesting Requirements and Habitat Preferences
Hornets are also attracted to environments that provide ideal conditions for building their communal paper nests. They seek out sites that offer protection from weather and predators, which often leads them to human-built structures. European hornets, for example, typically prefer dark, enclosed spaces such as wall cavities, attics, hollow logs, or abandoned sheds.
The construction of their durable, layered nests requires a constant supply of cellulose. Hornets chew and mix wood fibers with their saliva to create a strong, paper-like pulp. This need for building material can draw them to wooden fences, unpainted decks, or any accessible source of soft, exposed wood near a suitable nesting void.
Accessible water sources are also a factor in attracting hornets to a location. Water is essential for mixing the wood pulp to create nest material and for regulating the temperature inside the colony during hot weather. Areas with standing water, dripping faucets, bird baths, or swimming pools can be inadvertently attractive to a founding queen or foraging workers.
Inadvertent Human Attractants
Beyond food and habitat, hornets can be drawn to humans by non-food cues. Strong, sweet scents can mimic the floral nectar that hornets seek for energy. Heavily scented personal care products, including perfumes, body sprays, and fruity shampoos or lotions, can inadvertently signal a food source to a passing hornet.
Visual cues also attract their attention. Hornets are drawn to bright colors, particularly yellow and white, which can resemble flowers or prey. Wearing clothing with bright floral patterns or large blocks of color may increase the likelihood of investigation.
Rapid or erratic movements when a hornet is nearby can quickly transition the insect from curious forager to defensive threat. Swatting or flailing is interpreted as aggression, potentially triggering a defensive response. Remaining still and calm is the best course of action, as it prevents the hornet from perceiving the person as a threat.